Sun Coast Amateur
Radio Club Society

vhfops

Simplex

The most noticeable difference between a two-way radio and a cell phone is that with a two way radio, you can't talk and listen to the other person at the same time. The reason for this is that two-way radios typically share one frequency for transmitting and receiving. This mode of communication is called Simplex or Half-Duplex.¹⁾

Cellphones, on the other hand, use two frequencies at the same time: one for transmitting, and the other for receiving. This is called Full Duplex.

Full Duplex²⁾		Simplex³⁾

Full duplex is like a regular road where traffic has its own lane and can travel in both directions at the same time. Cells phones can do this.		Simplex (or Half-Duplex) is like only having one lane open and forcing traffic to alternate. Most two-way radios can only do this.

Since most of the voice communications we have with amateur radios are not full duplex, it's really important that operators wait until the other person is finished before beginning to speak otherwise they'll miss part of the conversation. When that happens, we say that the operators “doubled”, which means neither heard the other (although a third person may have heard both). We usually recommend waiting half a second or so before beginning to transmit. This also gives the chance to other stations to jump in if needed (with emergency traffic for example).

Range

A common question people often have is how far they can talk with a ham radio. This is a tricky question because the range depends on three main factors:

the antenna characteristics of both radios, their heights above the ground, and the line of sight between them.
the transmitting power of both stations.
the frequency band used (more on that later).

Depending on theses factors, two stations may barely be able to communicate to a kilometre, or have no problem making it all the way to the other side of the globe.

It's also a trick question because the range depends on the setup of both radio stations: it makes no sense to talk about the range of one radio.

Let's look at the first two factors now (we'll leave the third for later).

Antenna, Height, Line of Sight

The best way to improve your signal is to focus on the antenna system. A $2000 radio with a bad antenna system will do worse than a $100 radio with a great antenna system. The general principal is that an antenna should be the right type for the band used (much more on this later), as high as possible, and have a clear path to the other station.

For example:

Under “normal” conditions, two VHF hand held radios operating in simplex at 5 watts could probably communicate with one another to a distance of about 1 km. If the line of sight is obstructed by buildings or hills, this range would drop, but if one (or both) of the stations were at the top of a hill with a clear view of the valley below the range would increase.
A VHF base station with a good antenna up a tall tower might be able to communicate with a hand held radio 10 or 15 km away.
And two such base stations would probably be able communicate with one another to a distance of 50 to 100 km.

Again: it doesn't make sense to talk about the range of one radio; instead, the range depends on both stations. As soon as one station improves its antenna system and line of sight, both stations benefit.

Power

Personal radio services like CB or FRS require no license but have their power output regulated to a maximum of 4 Watts (for CB bands) and 2 Watts (for FRS bands). Ham radios, however, can be operated to hundreds of watts depending on the band, mode, and license type. This complicates the “range” question a bit.

For example, imagine that Alice and Bob can barely manage to hear each other at 5 W. What would happen if Alice cranks up her transmit (TX) power to 50 W? Would that help her hear Bob better?

Increasing your own power is like speaking louder: it helps others hear you better, but it doesn't help you hear them better. As such, one of the rules in ham radio is to use the minimum power required to make the contact. It's like adjusting the volume of your voice to the setting around you. You wouldn't shout to the person sitting in front of you in a quiet restaurant, but you might in a loud pub.

In general, it's best for both stations to try to match their TX power so that you're both “speaking” at an equal volume. If one person is transmitting at 50 W while the other is at 5 W, one person might not hear the other properly.

The rules⁴⁾ for how much power can be used are a little complicated because they depend on where it is measured in the radio and what kind of transmission is used. We'll see what these mean in more detail later, but for now, here's the summary:

	Basic	Advanced
DC input power to the anode or collector circuit of the transmitter stage that supplies radio frequency energy to the antenna	250W	1000W
Peak envelope output power measured across an impedance-matched load for SSB emissions	560W	2250W
Carrier output power measured across an impedance-matched load for any other type of emission.	190W	750W

So while an advanced license allows the use of roughly four times more power (which only improves the received signal by one S unit), having a better antenna doesn't require any special licensing and helps both stations at once, which is why it should be the number one focus.

Personal Record

The furthest VA7FI has been able to communicate in simplex on VHF (146.520 MHz) was 300 km away. The other station (KG7EGT) was atop of Summit Lake Peak (47.03969,-121.83162) at an elevation of 1650m in Washington State and VA7FI was using his GP-9 antenna up a 20m tall tree with the base of the tree 100m above sea level with a direct view of the water. VA7FI could hear KG7EGT 57 and KG7EGT could hear VA7FI 59. This difference in signal strength was because VA7FI was using full power on his base station while KG7EGT was using a portable radio with less power.

Frequency Coordination

As we saw on the previous page, ham operators are allowed to use very specific bands of the electromagnetic spectrum, but each band is also further sub-divided for different usage. The following links from Radio Amateur of Canada (RAC) should be printed and used as reference:

And for British Columbia:

Plan "A" by Functional Allocation

Let's use the 2m band as an example. Even though, we are allowed to transmit between 144 and 148 MHz, only the following frequencies should be used for simplex, voice operation:

146.415, 146.430, 146.445, 146.460, 146.475, 146.490, 146.505, 146.520, 146.535, 146.550, 146.565, 146.580, 146.595, 147.420, 147.450, 147.480, 147.510, 147.540, 147.570

You'll notice that the first 13 channels are 0.015 MHz (or 15 kHz) apart and the last 6 channels are 30 kHz apart. That's to ensure that someone talking on one frequency doesn't interfere with someone talking on another. For example, if a group is using 146.415 MHz and another is using 146.430 MHz, they probably won't bother each other, (unless they are really close to each other), but if you tune your radio to 146.420 MHz or 146.425 MHz, you might hear noise from both groups. That's because communications on a frequency also have what we call bandwidth. Radio signals never only take just “one” frequency. Instead, they take up a certain amount of space on the electromagnetic spectrum.

The fourth column of the table on the previous page shows the maximum allowed bandwidth for each band. This bandwidth is regulated so that no one station takes more space than needed, which would cause interference on the other frequencies.

The Radio

Now that we understand a bit more about simplex communications, let's look at some buttons on an actual radio to see what each does.

This particular radio is the Icom IC-2730A. The first thing to notice about this radio is that it's actually two radios in one. You can listen to two different frequencies at the same time, with their own independent volumes and dials. So looking at the left side for example, we see...

VFO / MR

Two buttons labelled V/MHz and MR. They simply allow the main DIAL to tune the radio either by frequency or by channels saved by the operator. On other radios, these two buttons are sometimes a single button labelled VFO / MR.

Squelch

The SQL (squelch) dial is a circuit within the radio that keeps the speaker silenced (squelched) until the signal level exceeds a certain point set by the squelch control. Normally you set the squelch to just block out noise and allow signals to pass. The reason for this is that there is always some radio background noise on the air. Sometimes that noise is low, but sometimes it's high. Being able to silence it depending on its intensity ensures that we may be able to hear weak stations that are just above that noise level.

CTCSS

Another feature hidden in the MENU of the radio is called CTCSS (Continuous Tone-Coded Squelch System) or sub-audible tone (or sometimes just called “tone”). Imagine that you reside in a congested area where there is a lot of interference that opens the squelch unnecessarily. What you and the other operator can do is send a specific tone (which is just a pure note) on top of your voice when you transmit. That way, you can set your radio to only open the squelch if that note is heard. Typically, there are 50 tones available to choose from ranging from 67.0Hz to 254.1Hz. Have a listen at three of them here:

67.0 Hz	67 Hz
151.4 Hz	151.4 Hz
254.1 Hz	254.1 Hz

You probably noticed that you had to use headphones or good speakers to hear them (at least for the first two tones). That's because, although they are within our normal range of hearing (20 Hz ‒ 20 kHz), the lower frequencies require bigger speaker to play properly. Which is why, we tend not to actually hear these tones over the radio when we use them.

That being said, there is a trade off when picking a tone: the lower frequency tones are the less likely to be heard but they take longer to be recognized by the radio because they take more time to go through a full cycle. That means that it's even more important to wait a half a second before speaking after keying up the PPT (Push To Talk) button to give time to the other radio to recognize the tone and open the squelch for you.

Microphone

The microphone on this particular radio contains some new buttons, but some that are also on the radio itself like the VFO/MR, VOL and SQL

PTT

The PTT (push to talk) is the button used to engage the transmitter and talk on the air. This is the button you must wait half a second before talking after you press it.

DTMF

The DTMF (Dual-tone Multi-frequency) buttons are the same as on a regular phone. They allow radios to transmit numbers and four letters to activate various functions on remote radios. For example, it's possible to configure some radios to have their squelch on (to silence any incoming transmission) until a specific sequence of DTMF is heard. More often, they're used to control repeaters (which we'll see next).

From wikipedia:

“The DTMF system uses a set of eight audio frequencies transmitted in pairs to represent 16 signals, represented by the ten digits, the letters A to D, and the symbols # and *. As the signals are audible tones in the voice frequency range, they can be transmitted through electrical repeaters and amplifiers, and over radio and microwave links, thus eliminating the need for intermediate operators on long-distance circuits.

The *, #, A, B, C and D keys are still widely used worldwide by amateur radio operators and commercial two-way radio systems for equipment control, repeater control, remote-base operations and some telephone communications systems.”

They are created by playing two notes at the same time:

	1209 Hz	1336 Hz	1477 Hz	1633 Hz
697 Hz	1	2	3	A
770 Hz	4	5	6	B
852 Hz	7	8	9	C
941 Hz	*	0	#	D

Repeaters

⁵⁾

To extend the range of VHF and UHF communications, repeater stations are often used. These stations are special radios located on mountain tops that have high quality antennas up tall towers. They work by listening on one frequency (the input) and automatically re-transmitting what they hear on another frequency (the output). The difference between the two frequencies is called the offset.

For example, to use VE7RXZ, individual radio stations need to transmit (TX) on 147.800 MHz (the repeater's input frequency) with a Tone of 100.0 Hz, but listen (RX) on 147.200 MHz (the repeater's output frequency).

In this case we'd say that the repeater frequency is:

147.200 MHz with a + offset of 600 kHz and a Tone of 100 Hz.

So two radio stations communicating through a repeater are not actually hearing each other's signals directly. Instead, they're hearing the repeater's signal, which is usually stronger and goes further.

At first glance, it might look like operating through a repeater would be a lot of work (with this constant flipping back and forth between two frequencies), but once radios are programmed with the proper RX frequency and offset, they will switch frequencies automatically when the Push-to-Talk (PTT) is button is pressed.

Repeater Frequency Coordination

In the same way that simplex frequencies are specified, the same is true for repeater frequencies. For example, here's a sample of http://wp.rac.ca/144-mhz-2m-page/:

With the following note:

“(10) Repeaters may include FM, ACSSB or digital modes of modulation. Consult with your local coordination body for frequency and modulation scheme allocations.”

What this means is that while there is a general agreement on which frequencies should be used for repeaters, the coordination of which repeater should use which specific frequency is managed at a more local level. In BC, the British Columbia Amateur Radio Coordination Council is responsible for coordinating repeater frequencies. Their website also includes pdf lists of repeaters.⁶⁾ Other provincial Coordination Council can be found on the RAC website.

In general, though, radios sold in Canada come pre-programmed with the following repeater offset scheme:

VHF (offset = 600 kHz)⁷⁾	UHF (offset = 5 MHz)⁸⁾
145.100 ‒ 145.500 MHz (-)	442.000 ‒ 445.000 MHz (+)
146.610 ‒ 146.970 MHz (-)
147.000 ‒ 147.390 MHz (+)

(-) means that the repeater's input is lower than its output and
(+) means that the repeater's input is higher than its output.

Repeater Use

To call someone, we always say their call sign first, then our own. To answer a call is more flexible, but the rules⁹⁾ say that each station has to identify themselves in either English or French:

at the beginning of the conversation,
at least every 30 minutes during the conversation, and
at the end of the conversation.

Suppose that Graham, VE7ABC, wants to call Linda, VE7XYZ on a local VHF repeater.

Graham would first tune in to the repeater's output frequency and wait a few seconds to make sure the repeater is not in use.
When ready, Graham would then say: “VE7XYZ, VE7ABC”
If Linda is there, she would reply something like: “VE7ABC, this is VE7XYZ. Go ahead Graham.”

During their conversation, Linda and Graham should keep each transmission short and leave about half a second between them to allow others to break in. Some repeaters have a courtesy tone (or Roger beep) after each transmission to help operators slow down. Most also have a time-out timer to interrupt lengthy transmissions without pause. That way, if someone wants to join in, all they'd have to do is say their call sign between transmissions and wait to be called.

So when Linda and Graham are done, they could close with something like this:

“Ok Linda, talk to you later. VE7ABC clear on your final.”
“Very good Graham. 73. VE7XYZ clear.

The rules on station identification are very important. The only time a station is allowed to transmit without identification is to remote control a model craft. Even repeaters have to identify themselves (usually in morse code, but not always).

The procedure to send a general call varies a bit depending on whether we are using a repeater or calling in simplex:

In simplex, we use the code “CQ”. So if Graham wanted to talk with anyone, and Linda replied, the exchange would look like this:

“CQ CQ CQ, this is VE7ABC, VE7ABC, VE7ABC”
“VE7ABC, this is VE7XYZ.”

On repeaters, we usually simply state our callsign:

This is VE7ABC listening.

Of course, all call signs should be given in phonetic, especially when sending and replying to a CQ call since the two operators may not know each other.

Repeater Etiquette

Since repeaters extend the coverage of VHF/UHF transmissions, they also extend the number of operators monitoring or potentially needing to use a given frequency. As such, the following etiquette should be followed:

Keep transmissions short.
Give enough time between transmissions for others to break in.
Move to a simplex frequency whenever possible.

To know if it's possible for you to communicate with someone in simplex, you can listen on the repeater's input when the other station is transmitting. If you can hear their direct signal well, then you can reach them in simplex. When choosing a simplex frequency, remember to use one of the 13 dedicated frequencies otherwise you could fall on the input of another repeater, or between two pre-determined channels.

Questions

B-001-013-002 → B-001-013-010
B-001-017-001 → B-001-018-001
B-002-001-001 → B-002-001-011
B-002-003-001 → B-002-003-008
B-002-004-001 → B-002-004-002
B-002-004-010

¹⁾

Technically, simplex refers to “a communication channel that sends information in one direction only.” However, “the International Telecommunication Union definition is a communications channel that operates in one direction at a time, but that may be reversible; this is termed half duplex in other contexts.” Simplex_communication

²⁾

Picture from: Duplex_(telecommunications)#Full-duplex

³⁾

Picture from: Duplex_(telecommunications)#Half_duplex

⁴⁾

See RBR-4 Sec. 10

⁵⁾

Picture modified from Repeater

⁶⁾

Another good place to find repeater frequencies is http://repeaterbook.com. They also have a phone app that's very convinient

⁷⁾

See http://wp.rac.ca/144-mhz-2m-page/

⁸⁾

See http://wp.rac.ca/432-mhz-70-cm-page/

⁹⁾

See RBR-3, p.1 and RBR-4, Sec 9

netcontroller

Net Controller Guidelines

A list of tips for net controllers.

Pause:

At the end of someone's transmission, leave a short pause before pressing the PTT; and after pressing the PTT, leave another short pause before speaking. This allows any parts of the repeater system that have delays to catch up (tone squelch, links, Echolink, IRLP, etc).
When calling for Echolink stations in particular, leave at least 4 seconds after the repeater has keyed down before moving on. Echolink doesn't allow the app to “transmit” until the repeater has been completely silent for a moment.

Acknowledgement:

When acknowledging a station, call them by their name or callsign so that they know you're talking to them. Sometimes there are doubles and people might might not be sure who you heard.

Intelligibility:

Speak slowly, not everyone has great hearing or facilities with your particular manner of speech.
Use the standard phonetics. People get good with their own callsign, but to a stranger, it just sounds like random letters.

ID Requirements:

If the net lasts for more than half an hour, remember to ID before the half hour mark to follow ISED regulation.¹⁰⁾

¹⁰⁾

See RBR-3, p.1 and RBR-4, Sec 9

mathbasics

Metric Prefix

A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or fraction of the unit.

In the previous section, we saw that MHz means a million Hertz. Here's a list of the most common ones:

Name	Symbol	Base 10	Decimal
Tera	T	10¹²	1 000 000 000 000
Giga	G	10⁹	1 000 000 000
Mega	M	10⁶	1 000 000
Kilo	k	10³	1 000
hecto	h	10²	100
deca	da	10¹	10
		10⁰	1
deci	d	10^-1	0.1
centi	c	10^-2	0.01
milli	m	10^-3	0.001
micro	μ	10^-6	0.000 001
nano	n	10^-9	0.000 000 001
pico	p	10^-12	0.000 000 000 001

The decibel

A decibel (dB) is a way of saying how many times bigger (or smaller) something is compared to something else. For example, let's use the faintest sound that the human ear can detect as the basis. A normal conversation would be a million times louder, and a jack hammer would be a hundred billion times louder. To represent these vast differences in numbers, we use a logarithmic scale based on powers of 10.

Here's the idea. Start with representing numbers by exponents of 10:

Number	Base 10	Exponent
1 =	10⁰	0
10 =	10¹	1
100 =	10²	2
1000 =	10³	3
10 000 =	10⁴	4
100 000 =	10⁵	5
1 000 000 =	10⁶	6

If your math is a little rusty, notice how the exponent counts the number of zeros after the one (1 000 000 has 6 zeros so it's equal to 10⁶)

For now, let's call the exponent a “bel” (not decibel yet). For example:

Instead of saying that a sound is 1000 times louder, we could say that it's 3 bels louder, and
Instead of saying that it's 10,000 times louder, we could say that it's 4 bels louder.

So the bel is just the number of zeros after the 1. But what if the number doesn't start with 1. For example: what if it's 5000 times louder?

Since 5000 is between 1000 and 10,000, it might be tempting to say that it would 3.5 bels louder (midway between 3 and 4), but let's check to see if it works: 10^3.5 = 3162, which is between 1000 and 10,000, but not 5000.
By trial and error, you might get pretty close: 10^3.7 = 5011... so 5000 times louder is roughly 3.7 bels.
But a faster way of finding the exponent of a base 10 number is to use the Log button on your calculator: \$\log(5000) \approx 3.699\$¹¹⁾

In the same way that milli means a thousandth, and centi means a hundredth (think millimetre and centimetre), a deci means a tenth. So 1 bel contains 10 decibels (like 1 metre contains 10 decimetres, 100 centimetres, or 1000 millimetres).

So another way of saying 3.7 bels is to say 37 decibels, or 37 dB. So here's our table again with a few common “in between” numbers:

Number	Base 10	Exponent (bels)	decibels (dB)
1 =	10⁰	0	0
2 ≈	10^0.3	0.3	3
4 ≈	10^0.6	0.6	6
8 ≈	10^0.9	0.9	9
10 =	10¹	1	10
100 =	10²	2	20
1000 =	10³	3	30
10 000 =	10⁴	4	40
100 000 =	10⁵	5	50
1 000 000 =	10⁶	6	60

In addition to being more convenient to represent big numbers, decibels also allow us to multiply big (or small) numbers more easily by adding the dB instead. For example, look at:

100 x 1000 = 100,000

Let's write the same thing again in powers of 10:

10² x 10³ = 10⁵

Notice that while the numbers are multiplying (100 x 1000), the exponents are adding (2 + 3). So 100 x 1000 is the same as saying 20 dB + 30 dB = 50 dB. That is, adding the dB representation of numbers, is the same as multiplying those numbers.

Look back at the previous table; if you double the power, three times in a row:

The final power is 2 x 2 x 2 = 8 times more powerful than the original.
In terms of dB, we can instead add 3dB three times: 3dB + 3dB + 3dB = 9dB.

Here's a quick exercise: Using only the table above, what is the dB representation of 4000?

Click to display ⇲

Click to hide ⇱

A 4000 fold increase is the same as a 1000 fold followed by two doubling. That is:

1000 x 2 x 2 = 4000

Which means:

30dB + 3dB + 3dB = 36dB

Quick calculator check: 10^3.6 = 3981 ≈ 4000

So the only thing to memorize with decibels is that:

a bel (10 dB) is the number of zeros after the 1. So that takes care of knowing 10dB, 20dB, 30dB, ...
3dB is one doubling.

With these two things, we can now estimate a bunch of in between numbers like 36dB (30dB + 3dB + 3dB), or 13dB (10dB + 3dB)

Here's Dave explaining this in more details:

Alternative Formulation

If you like formulas, what I did above was define the dB implicitly as:

\$$ \text{ratio} = 10^{\left(\frac{\text{dB}}{10} \right)} \$$

For example, a ratio of 1000 is equivalent to 30 dB because:

\$$ 1000 = 10^{\left(\frac{\text{30}}{10} \right)} \$$

But what you'll often find in books is the following explicit definition:

\$$ \text{dB} = 10\log\left(\text{ratio}\right) \$$

While the two are definitions are mathematically equivalent¹²⁾, I personally prefer the implicit definition because I find it easier to picture the dB in terms of powers of 10, where as I can't really picture the log function that well. But they are equivalent, so use the one you like most.

dBm

A related measurement is the dBm. While the decibel (dB) is a ratio between two quantities (saying “20 dB” is the same as saying “100 times more”), the dBm is a ratio between one quantity and 1 mW. That is, it's a measure of how much stronger (or weaker) the power of something is compared to 1 milliwatt.

For example, a typical fibre optic light signal to a house for internet has a light level of -16 dBm. Before we go through the math, recall that \$16 \text{ dB} = 10 \text{ dB} + 3 \text{ dB} + 3 \text{ dB}\$. Which means, the ratio is \$10 \times 2 \times 2 = 40\$. Let's now see why -16 dBm is equal to a power of 25 μW (microwatts):

\$$-16 \text{ dBm} = 1 \text{ mW} \div 10^{1.6} \approx 1 \text{ mW} \div 40 = 0.025 \text{ mW} = 25~\mu \text{W} \$$

Notice how the minus sign in front of the dBm means that the power is less (not more) so it divides (not multiply).

Binary Numbers

Base 10

It's kind of weird explaining how to count in base 10 because we're so used to it. But to understand other bases, it helps to understand how base 10 really works first.

So base 10 means we have 10 different symbols to represent numbers, and when we need more, we just add more digits to the number. For example, let's count and pay close attention to what we're really doing:

With one digit, we can count to nine because we have ten symbols: \$$0, 1, 2, 3, 4, 5, 6, 7, 8, 9\$$

To continue past nine, we need to add a new digit in front of the “counting digit”, and then we just do what we did above again: \$$10, 11, 12, 13, 14, 15, 16, 17, 18, 19\$$

And that new digit will increase in the same way until we run out of symbols: \$$20, 21, 22, 23, 24, 25, 26, 27, 28, 29\$$ \$$ 30, 31, 32, 33, 34, 35, 36, 37, 38, 39\$$ \$$\vdots \$$ \$$ 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 \$$

At which point we need to add a third digit (and so on).

It's strange to think about this but the ability to count is completely separate from having a sense of how big the numbers are. What I mean is: if you know how to change the symbols (from 0 to 1, and 1 to 2, and 2 to 3, etc) and how to add new digits (9 to 10, 99 to 100, ...) you can count forever without having a “number sense”. In base 10, it's hard to imagine not knowing how big a number is, but we'll actually do this in base 2 in a moment. You'll see, it's a weird feeling!

But first, here's another weird way to think of numbers. Take 234 for example. Let's “decompose” it into its powers of 10:

\begin{align*} {\color{teal}{234}} &= {\color{teal}2}\times 100 + {\color{teal}3}\times 10 + {\color{teal}4}\times 1 \\ &= {\color{teal}2}\times 10^2 + {\color{teal}3}\times 10^1 + {\color{teal}4}\times 10^0 \end{align*}

This is a very tedious way of expressing a simple number, but I promise it'll be invaluable when we try to convert from base 2 to base 10 in a moment (can you think of why?).

Base 2

Now let's do the same thing again in base 2. Imagine we only have two symbols we can use to count: 0 and 1. Let's see what counting to fifteen looks like starting at zero:

0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111

Do you see the pattern? Here's another way of writing it with leading zeros and keeping track of where we are in base 10:

Base 2	Base 10
0000	0
0001	1
0010	2
0011	3
0100	4
0101	5
0110	6
0111	7
1000	8
1001	9
1010	10
1011	11
1100	12
1101	13
1110	14
1111	15

You see what I mean about being able to count without knowing how big the number is? All we're doing is “flipping bits” from 0 to 1 in the right order. If we wanted, we could count to 1001010011010 and have no idea of how big that number is unless we kept track of it in base 10. That's because over the years, we developed a number sense for base 10 numbers, but we didn't for base 2 numbers since we don't typically use them.

Conversion

Now let's look at how to convert from one base to the other without counting.

Base 2 to Base 10

We'll use our example of 1101 in base 2 since we already know it's 13 in base 10. Before we do this, however, let's use subscripts to denote the base. For example, we'd write:

\$$ 1101_2 = 13_{10} \$$

Now let's see how we convert from base 2 to base 10 without counting. In the same way that each position in base ten is a factor of 10, each position in base 2 is a factor of 2:

\begin{align*} {\color{teal}{1101}}_2 &= {\color{teal}1}\times 2^3 + {\color{teal}1}\times 2^2 + {\color{teal}0}\times 2^1 + {\color{teal}1}\times 2^0 \\ &= {\color{teal}1}\times 8 + {\color{teal}1}\times 4 + {\color{teal}0}\times 2 + {\color{teal}1}\times 1 \\ &= 8 + 4 + 0 + 1 \\ &= 13_{10} \end{align*}

Let's try that again with the crazy number I mentioned earlier: 1001010011010. Skipping the powers with a coefficient of 0 (to save space): \begin{align*} 1001010011010_2 &= 2^{12} + 2^9 + 2^7 + 2^4 + 2^3 + 2^1 \\ &= 4096 + 512 + 128 + 16 + 8 + 2 \\ &= 4762_{10} \end{align*}

Base 10 to Base 2

Converting the other way around is a bit different, but kind of makes sense if you think about it. Here are the steps to convert \$ 13_{10} \$ back to \$1101_2\$ and I'll explain a bit more after:

Division by 2	In Decimal	As fraction	Quotient	Remainder
13÷2	6.5	6 + \$\frac{1}{2}\$	6	1
6÷2	3.0	3 + \$\frac{0}{2}\$	3	0
3÷2	1.5	1 + \$\frac{1}{2}\$	1	1
1÷2	0.5	0 + \$\frac{1}{2}\$	0	1

Now we read the remainders from the bottom up: 1101.

Recall that the remainder is what's left of a division; it's not the decimal portion. For example:

\begin{align*} 22 \div 5 &= 4.4 \\ &= 4 \tfrac{2}{5} \\ &= 4 \text{ remainder 2 (of 5)} \end{align*}

In our case, the remainder is what's left after we divided by 2. So why does this method work?

What we really want to do is decompose 13 into the sum of its powers of 2. That is: \begin{align*} 13_{10} &= \; 8 + 4 + 0 + 1 \\ &= \; 2^3 + 2^2 + 0 + 2^0 \\ &= (1 \quad \ \ 1 \quad \ \ \, 0 \quad \ 1)_2 \end{align*}

When we have a non-zero power of 2, we represent that position with a 1, when we have a zero power of 2, we write 0.

What the table above is doing is systematically dividing by 2 to see if the result is a whole number or not. If it is, it means that that position is 0 because the factor of two can be absorbed further up the chain. For example, the fact that 13 ÷ 2 = 4.5 means that the first digit has to be 1.

Let's look at a trivial example converting 2037 from base 10 to base 10 (trivial indeed!):

Division by 10	In Decimal	As fraction	Quotient	Remainder
2037÷10	203.7	203 + \$\frac{7}{10}\$	203	7
203÷10	20.3	20 + \$\frac{3}{10}\$	20	3
20÷10	2	2 + \$\frac{0}{10}\$	2	0
2÷10	0.2	0 + \$\frac{2}{10}\$	0	2

Other Bases?

There are other useful bases such as hexadecimal (base 16). Here's an example of counting to twenty in hex:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, 12, 13, 14

The convention to denote a hexadecimal number is to use either \$ 14_{16} \$ or 0x14.

The same logic applies to convert between hexadecimal and base 10:

\begin{align*} \text{F61B}_{16} &= 15 \times 16^3 + 6 \times 16^2 + 1 \times 16^1 + 11 \times 16^0 \\ &= 15 \times 4096 + 6 \times 256 + 1 \times 16 + 11 \\ &= 63003_{10} \end{align*}

One reason why hexadecimal is so useful in computer science is because one hexadecimal “digit” can represent four binary “digits”. For example,

Decimal	Hexadecimal	Binary
1	1	1
2	2	10
3	3	11
4	4	100
...
7	7	111
8	8	1000
...
15	F	1111
16	10	1 0000
...
31	1F	1 1111
32	20	10 0000
...
63	3F	11 1111
64	40	100 0000
...
127	7F	111 1111
128	80	1000 0000
...
255	FF	1111 1111
256	100	1 0000 0000
...
4095	FFF	1111 1111 1111
4096	1000	1 0000 0000 0000

¹¹⁾

Depending on your calculator, you might have to type it in this order 5000Log

¹²⁾

These two definitions are equivalent because the log function is the inverse of the power function. That is, it helps us find the exponent when we know the other quantities. Mathematically, we say that: \$a = 10^b \quad \Leftrightarrow \quad b = \log_{10}(a) \$

wavemodulationmath

More Details: AM / FM

Here are a few more details about the AM, SSB, and FM modulation schemes introduced on the Wave Modulation page.

For both AM and FM examples, we'll let:

\$c(t) = \cos(2 \pi f_c t)\$ be the radio carrier with frequency \$f_c\$
\$s(t) = \cos(2 \pi f_s t)\$ be the baseband audio signal with frequency \$f_s\$

With the radio carrier frequency several times greater than the baseband audio signal.

AM

The resulting Amplitude Modulated radio wave is the product of the vertically shifted baseband signal and the radio carrier, which is also equal to the sum of the carrier and the two side bands:

\begin{align*} \Big(s(t)+1\Big) \times c(t) &= \Big(\cos(2 \pi f_s t) + 1\Big) \times \cos(2 \pi f_c t) \\ &= \cos(2 \pi f_s t)\cos(2 \pi f_c t) + \cos(2 \pi f_c t)\\ &= \underbrace{\frac{1}{2} \cos\Big(2 \pi (f_c + f_s) t\Big)}_\text{USB} + \underbrace{\frac{1}{2} \cos\Big(2 \pi (f_c - f_s) t\Big)}_\text{LSB} + \underbrace{\cos(2 \pi f_c t)}_\text{Carrier} \end{align*}

In line 1, I distributed the bracket, which, in line 2, gave us the carrier (last term) and a product (first term). To expend this product into the sum of the two side bands (line 3), I added these two trig identities together:

\begin{align*} \cos(A+B) =& \cos(A)\cos(B) - \sin(A)\sin(B) \\ \cos(A-B) =& \cos(A)\cos(B) + \sin(A)\sin(B) \end{align*}

Which gives:

\begin{align*} &\cos(A+B) + \cos(A-B) = 2 \cos(A)\cos(B) \\ \Rightarrow &\cos(A)\cos(B) = \frac{1}{2}\cos(A+B) + \frac{1}{2}\cos(A-B) \end{align*}

Use this animation to see what happens when you vary the individual frequencies. You can use the check boxes to show or hide different waves.

: animation in wrong place

Download am.ggb

Some things to try:

Set \$f_s\$ at 10 and \$f_c\$ at 200 and check only the transmitted signal. You can easily imagine what the envelope (the baseband signal) should be that produced that signal. But...
Decrease \$f_c\$ slowly. At some point (around 20 or 30) the baseband signal becomes unrecoverable. This illustrates the point that to transmit a high frequency baseband, a higher frequency carrier is needed (at least 3 to 4 times the frequency of the baseband signal. This is why with digital signals, the higher the transfer speed, the higher the carrier frequency needs to be.

Mixer

Later on, we'll see that a mixer is an electronic component that multiplies two waves together, resulting in four different frequencies: \$f_1, f_2, f_1+f_2, \text{ and } f_1 - f_2\$. Although it's not modulation, the math is very similar to the way AM is created, so this is a good place to have a look at it. So let's multiply two very general waves with the following properties:

Amplitudes \$A_1\$ and \$A_2\$
Frequencies \$f_1\$ and \$f_2\$
Phases (horizontal shift) \$\phi_1\$ and \$\phi_2\$
DC components (vertical shift) \$c_1\$ and \$c_2\$

\begin{align*} \Big( A_1 \cos(2 \pi f_1 t + \phi_1) + c_1 \Big) \times & \Big( A_2 \cos(2 \pi f_2 t + \phi_2) + c_2 \Big) \\ \\ = & A_1 A_2 \cos(2 \pi f_1 t + \phi_1) \cos(2 \pi f_2 t + \phi_2 ) \\ & + c_2 A_1 \cos(2 \pi f_1 t + \phi_1 ) + c_1 A_2 \cos(2 \pi f_2 t + \phi_2) + c_1 c_2 \\ \\ = & \frac{A_1 A_2}{2} \cos(2 \pi (f_1+f_2) t + (\phi_1+\phi_2)) + \frac{A_1 A_2}{2} \cos(2 \pi (f_1-f_2) t + (\phi_1-\phi_2)) \\ & + c_2 A_1 \cos(2 \pi f_1 t + \phi_1 ) + c_1 A_2 \cos(2 \pi f_2 t + \phi_2) + c_1 c_2 \end{align*}

The last line looks like a real mess, but all it says is that the result is:

A wave with amplitude \$\frac{A_1 A_2}{2}\$, frequency \$f_1 + f_2\$, and phase \$\phi_1 + \phi_2\$
A wave with amplitude \$\frac{A_1 A_2}{2}\$, frequency \$f_1 - f_2\$, and phase \$\phi_1 - \phi_2\$
A wave with amplitude \$c_2 A_1\$, frequency \$f_1\$, and phase \$\phi_1\$
A wave with amplitude \$c_1 A_2\$, frequency \$f_1\$, and phase \$\phi_2\$
A DC component of \$c_1 c_2\$

A mixer is useful to raise or lower the frequency of a signal. For example, if a signal at 13 Mhz is mixed with a local oscillator signal at 14 MHz, two new signals will be produced (in addition to the original two): one at 1 Mhz and the other at 27 Mhz. If we want the higher one, we can put the result through a high pass filter, which will discard the unwanted signals.

FM

Mathematically, FM is less intuitive and more complicated than AM to understand. The first step is to modulate the frequency by adding a scaled baseband function to it:

\$$2\pi f_c \quad \rightarrow \quad 2\pi f_c + 2\pi k s(t)\$$

Here, \$f_c\$ is the frequency of the carrier, which is a constant (this is important),
and \$k\$ is a scaling factor we can use to decide how much of a variation we allow the baseband signal to impart on the carrier frequency. When \$k = 0\$, there is no modulation, and the greater \$k\$ becomes, the bigger the effect is.

It might be tempting to simply substitute this sum in the wave like so:

\$$ \cos(2\pi f_c t) \quad \rightarrow \quad \cos\Big(\big(2\pi f_c + 2\pi k s(t)\big) t\Big) \$$

but that's not quite right because the frequency is derived from the change in angle.

To solve this properly, we need some calculus to deduce the angle from our new frequency:

\$$ \frac{d}{dt}\theta(t) = 2\pi f_c + 2\pi k s(t) \qquad \Rightarrow \qquad \theta(t) = 2\pi f_c t + 2\pi k \int_0^{t}s(\tau) d\tau \$$

The frequency modulated transmission is actually given by:

\$$ \cos\Big(2\pi f_c t + 2\pi k \int_0^{t}s(\tau) d\tau\Big) \$$

In our particular example, with \$s(t) = \cos(2 \pi f_s t)\$, the modulated radio signal becomes:

\begin{align*} \cos\Big(2 \pi f_c t + 2\pi k \int_0^{t}s(\tau)d\tau\Big) &= \cos\Big(2 \pi f_c t + 2\pi k \int_0^{t}\cos(2 \pi f_s \tau)d\tau\Big) \\ &= \cos\Big(2 \pi f_c t + k \sin(2 \pi f_s t)\Big) \end{align*}

For more details about FM, see: http://www.ece.umd.edu/~tretter/commlab/c6713slides/ch8.pdf

Use this animation to see what happens when you vary the individual frequencies. You can use the check boxes to show or hide different waves.

: animation in wrong place

Download fm.ggb

Some things to try:

Set \$f_s\$ at 10 and \$f_c\$ at 200 and check only the transmitted signal. Notice how when the baseband is high, the transmitted wave is “tight” (ie, its frequency is high), and vise-versa. But...
Decrease \$f_c\$ slowly. At some point (around 20 or 30) that pattern becomes unnoticeable. Again, this illustrates the point that to transmit a high frequency baseband, a higher frequency carrier is needed (at least 3 to 4 times the frequency of the baseband signal. This is why with digital signals, the higher the transfer speed, the higher the carrier frequency needs to be.
Increase and decrease k to see the effect it has on the transmitted wave. The greater k, the more bandwidth the resulting signal uses. This dictates the difference between “Narrow Band FM” and “Wide Band FM”.

See https://electronicspost.com/narrow-band-fm-wide-band-fm/

PM

Phase Modulation is not usually discussed in ham radio courses, but after understanding FM, we pretty much get PM for free... Recall that for the wave \$\cos(2\pi f + \phi)\$, \$f\$ is the frequency and \$\phi\$ is the phase shift. For a pure tone, both of these are constant.

With FM, we saw that modulating the frequency led to \$\cos\Big(2 \pi f_c t + 2\pi k \int_0^{t}s(\tau)d\tau\Big)\$.
With PM, it leads to \$\cos\Big(2 \pi f_c t + 2\pi k s(t)\Big)\$

Essentially, with PM, we simply let \$\phi\$ vary with the baseband \$s(t)\$. But the thing to notice is that PM looks a lot like FM. In fact, an FM signal modulated by \$s(t)\$ is the same as a PM signal modulated by \$\int_0^{t}s(\tau)d\tau\$. In other words, the receiver needs to know if the signal was modulated in FM or PM since both wave forms look similar.

wavemodulation

Properties of Waves

Here we dive a little more deeply into waves and look at three ways that a “pure” radio wave (called the carrier) can be modulated to encode a voice signal (called the baseband signal): AM, SSB, FM.

But first, let's look at the general characteristics of a wave.

Amplitude, Wavelength, Frequency, and Period

Here are two moving waves (press the play button on the bottom left corner of the picture). What's different about them? What's the same?

Download travelingwave.ggb

Imagine that the dots moving up and down create the waves that are travelling to the right (as we'll see later, this is kind of like how radio waves are created). Here are a few things to notice:

The Blue wave is twice as “tall” as the green wave.
Both waves are travelling to the right at the same speed.
The Blue dot is moving up and down three times as fast as the green dot.
The Blue wave is three times as compressed as the green wave.

To quantify these observations more precisely, let's look at a snapshot of both waves frozen in time.

the amplitude is the vertical height from the centre of the wave to its highest (or lowest) point. The blue wave has an amplitude of 2 and the green wave has an amplitude of 1.
the wavelength is the horizontal distance of one full cycle. The blue wave has a wavelength of 2m and the green wave has a wavelength of 6m.

Now imagine that the animation is in super slow motion and that the waves are actually travelling at the speed of light, which is roughly 300,000,000 metres per second: How many times does each dot go up and down in one second?

Another way of asking that question is: how many full cycles can you fit in 300,000,000 metres (since radio waves travel 300,000,000 metres each second).

Since the blue wave has a wavelength of 2m, it'll take 150,000,000 cycles to reach 300,000,000 metres. That means that the blue dot oscillates at 150,000,000 cycles per second, or 150,000,000 Hz, or 150 Mhz
Similarly, since the green wave has a wavelength of 6m, its frequency is 50 Mhz.

So a quick way to relate the frequency \$f\$ (in MHz) and the wavelength \$\lambda\$ (in metres) is:

\$$ \lambda = \frac{300}{f} \qquad \text{or} \qquad f = \frac{300}{\lambda}\$$

Note that the reason we're using just 300, instead of 300,000,000 is that we've cancelled six of the zeros so that the frequency is in MHz instead of in Hz.

Now, here's a related question: how long does it take for each wave to complete one cycle?

For the blue wave, we know that it oscillates 150,000,000 times / second, so only one of those time would take 150,000,000^th of a second, or \$\frac{1}{150,000,000}\$ s or 6.67×10^-9 s or 6.67 ns.¹³⁾
Similarly, the green wave oscillates at 50,000,000 cycles per second, so only one of those cycle would take \$\frac{1}{50,000,000}\$ s or 2×10^-8 s or 20 ns.

The time to complete one full cycle is called the period (T) and is the reciprocal of the frequency:

\$$T = \frac{1}{f} \qquad \text{or} \qquad f = \frac{1}{T}\$$

Wave Addition

When two waves overlap, they add up together at every point. Here, the blue and green waves are generated and add up together to form the red wave. You can move the blue and green waves and see the result. To convince yourself that the red wave is really the sum of the blue and green waves, look at points A, B, and C. You can move the blue or green waves by sliding their phase (φ and Φ) around. You'll see that point C is always the sum of A and B.

Download waveaddition.ggb

Where do the blue and green waves need to be so that...

the red wave is the biggest?
the red wave is cancelled out?¹⁴⁾

If you press the play button on the bottom left corner, you'll see the blue wave travel to the right and the green wave travel to the left. The red wave, which is the sum of the forward and reflected waves, oscillates up and down but doesn't travel anywhere, which means it's not going into the antenna.

While the animation is running, slowly decrease the amplitude of the reflected wave (V_B) and you'll see that the red wave will start moving to the right. As you do that, notice how the SWR (Standing Wave Ratio) decreases toward 1:1. At this point, there is no reflected wave and all of the energy is going to the antenna (assuming no loss in the feedline).

Modulation

Modulation is the process of “encoding” a message (be it voice or digital) onto a radio wave.

Activity

If you have access to an HF radio:

Tune in to an AM signal and notice what happens as you slowly move off frequency:
1. How does the quality of the audio change?
2. How far can you go before you can't understand the audio anymore?
Tune in to an SSB signal and notice what happens as you slowly move off frequency:
1. How does the quality of the audio change?
2. How far can you go before you can't understand the audio anymore?

AM

AM stands for Amplitude Modulation. What this means is that the transmitted radio wave is obtained by changing the amplitude of a pure radio waves (the carrier) based on an audio signal (the baseband).

For example, let's transmit a single audio note of 10 kHz at a radio frequency of 200 kHz.¹⁵⁾:

Before we modulate the carrier, we raise the audio signal above zero to get an envelope:

Finally, we multiply the envelope and the carrier, which gives us a wave that has the same frequency as the carrier, but an amplitude that varies like the voice signal:

So very roughly:

AM Radio Wave = (Audio Signal + 1) × Carrier Wave

Let's pause for a minute and highlight that here, we are multiplying two waves together (not simply adding them). Later on, we'll see that the electronic component that does that is called a mixer, not to be confused with a sound mixer, which does do addition.

The incredible thing about the resulting AM broadcast is that the transmitted radio signal can also be seen as the sum of three pure sine waves:

AM Radio Wave = LSB Wave + Carrier Wave + USB Wave

LSB means Lower Side Band
USB means Upper Side Band

This is absolutely not obvious but let's see why it's at least plausible. Imagine we start with the following three waves:

An LSB Wave oscillating at 190 kHz with an amplitude of 0.5
A Carrier Wave oscillating at 200 kHz with an amplitude of 1
A USB Wave oscillating at 210 kHz with an amplitude of 0.5

Now let's add them together. This is a bit of a mess, but let's look at specific places along the waves:

at point A, all three waves align so the sum is: 0.5 + 1 + 0.5 = 2
at point B, the two side bands are opposite and cancel each other and only the carrier remains: 0 + 1 + 0 = 1
at point C, the carrier is opposite the two side bands so the sum is: -0.5 + 1 - 0.5 = 0
at point D, the same as point B is happening
at point E, the same as point A is happening

The result is the same as final AM signal:

Note that the carrier has a frequency of 200 kHz just like the original carrier, but the two side bands are 10 kHz lower and higher with half of the amplitude. Notice also how the LSB Wave oscillates slower than the Carrier Wave, while the USB Wave oscillates faster.

Frequency Spectrum

An easier way to represent a radio signal is using a spectroscope, which shows the frequency spectrum of a wave. That is, instead of looking at the signal wave itself, the spectroscope shows the strength of each frequency that makes up the sum of the signal.

For example, the spectrum of our 10 kHz note transmitted over a 200 kHz carrier would look like this:

All this is saying is that the radio signal is composed of three pieces: a signal at 190 kHz with an amplitude of 0.5, a signal at 200 kHz with an amplitude of 1, and another at 210 kHz with an amplitude of 0.5.

There are three things to notice here:

The two side bands are 10 kHz on each side of the carrier (same as the baseband signal!). It is that distance away from the carrier that represents the audio signal we want to recover.
Most of the power is going into transmitting the carrier, which in itself doesn't carry any information, so that's a bit of a waste of energy.
More fundamentally: even though we say that the signal is transmitted at 200 kHz, in this example, it is really contained between 190 kHz and 210 kHz. That is, it has a bandwidth of 20 kHz (210 kHz - 190 kHz). This bandwidth is regulated and depends on the band used.

SSB

One way of saving power (and reduce bandwidth) is to only transmit one of the side bands. In this example, the radio would be tuned to 200 kHz, but...

...for LSB, the spectroscope would look like:

...for USB, the spectroscope would look like:

By itself, neither of these transmissions would carry the information we need (that the baseband signal was a 10 kHz note) since it's the difference between the sideband and the carrier that gives us that information. But if the receiver knows that this signal was generated by a transmitter at a frequency of 200 kHz, then the receiver can re-inject the missing carrier on its side.

This is why an AM signal is not too picky about being slightly off frequency (both the sidebands and the carrier are transmitted). But a SSB signal changes pitch if the receiver is not tuned precisely to the transmitter frequency.

In reality, the voice we transmit contains a whole group of “notes” typically between 300 Hz and 3000 Hz (music could range between 20 Hz and 20,000 Hz). A typical voice signal (baseband) could look something like this:¹⁶⁾

So the AM signal would look like this:

Notice how:

the carrier is a single line in the centre because unlike the sidebands, it is a pure sine wave of only one frequency.
the two side bands are mirror images of each, which is why it's important that both the receiver be in the same mode as the transmitter.

And finally, each individual sideband would look like this:

The two main advantages of using SSB (LSB or USB) are that:

It takes less power to transmit the same information.
It takes half the bandwidth.

Here's a screenshot of VA7FI's IC-7300 scope showing both modes on the same screen:

The radio is tuned to 3.880 MHz (where no one is transmitting), but there are two neighbouring conversations going on:

one at 3.875 MHz using LSB,
and another at 3.885 MHz using AM.

The scope shows the recent history of the radio signal (called waterfall) where the present is at the top and the past at the bottom. Blue represent a weak signal strength and yellow or red represent a strong signal strength. Here are some things to notice:

	LSB (3.875 MHz)	AM (3.885 MHz)
Symmetry	The signal is on the left (low side) of where the carrier would be (at 3.875 MHz) and varies with speech.	The signal has a strong, constant carrier in the centre, and two symmetrical sides that vary with speech.
Bandwidth	About 2.7 kHz on the low side of 3.875 MHz	About 6 kHz (2.7 kHz on each side of 3.885 MHz, with two gaps near the carrier)
Pauses	During pauses, no radio signal is transmitted.	During pauses, the carrier is still transmitted.
Relationship	An AM signal can be understood in LSB mode because it contains the lower side band required. But an LSB signal can't be understood in AM mode because both sidebands and the carrier are needed to process the signal.

FM

FM stands for Frequency Modulation. What this means is that the transmitted radio wave is obtained by changing the frequency of the carrier based on the audio signal.

For example, let's again transmit a single audio note of 10 kHz at a radio frequency of 200 kHz using FM this time instead of AM:

This time, we don't simply multiply the baseband signal to the carrier (as in AM). Instead, we “compress” and “stretch” the carrier (ie, modulate its frequency) based on the baseband signal.

Here, the math is a bit more involved and requires at least 1^st year calculus to understand but in a nutshell, if the carrier is \$ c(t) = \cos(2 \pi f_c t) \$ and the baseband signal is \$s(t)\$, then the FM signal will be:

\$$ \cos\Big(2 \pi f_c t + 2 \pi k \int_0^t s(\tau) d\tau\Big) \$$

If this looks like Greek to you, don't worry; the math isn't important. The key concept to understand is that the highs and lows of the baseband signal are encoded in the horizontal compression (the frequency) of the radio wave: When the baseband is high, the radio signal is more compressed (its frequency is higher), and when the baseband is low, the radio signal is more stretched out (its frequency is lower).

Optional Details

For those interested in some of the mathematical details, see this optional page.

¹³⁾

“ns” means nanosecond. “Nano” means a billionth of ___

¹⁴⁾

Fun fact: This is how noise cancelling headphones work. The headset has a microphone that picks up the noise, inverts the waves, and plays them back in the ear piece. The combination of the real life noise and the inverted noise being played in the speaker cancel out (somewhat).

¹⁵⁾

Note that 200 kHz is lower than commercial AM broadcast and is not a ham radio frequency. I chose a ratio of 20:1 so we can see the effects on the graph

¹⁶⁾

The next few images are from Single-sideband_modulation

intro

Intro to Radio Waves

Before we can start discussing Amateur (Ham) Radio, we need to talk a little bit about radio waves. We'll explore this topic in much more detail later on, but for now, let's look at some foundational concepts.

Imagine the radio in your car could not only listen but also transmit on any frequency you like. What would happen as you move up and down the dial?¹⁷⁾

Starting in the FM radio range, let's turn the dial down:

At 88.1 MHz, you'd be transmitting on top of CBC Radio 1 FM (in the Vancouver area).
At 0.690 MHz (or 690 kHz) you'd be transmitting on top of CBC Radio 1 AM (in the Vancouver area).
Around 1 kHz (or 1000 Hz) you'd be interfering with military submarine radio communications.

At this point, you should start thinking about the relationship between MHz, kHz, and Hz. We'll add more to the list below.

There's a lot of stuff in between, but it's pretty much radio waves all the way down. However, turning the dial above the FM radio stations yields some surprises:

At 2.4 GHz (or 2400 MHz) and 5.8 GHz (or 5800 Mhz), you'd be interfering with WiFi signals.
Between 30 and 120 THz (30,000 and 120,000 GHz), you'd be in the mid-infrared range and your antenna would start to feel warm.
At 400 THz, the antenna would start glowing red.¹⁸⁾ By increasing the frequency, you'd go through all the colours of the rainbow until the last purple would vanish around 790 THz.
Between 790 THz and 30 PHz (30,000 THz) you'd create UV rays, which are invisible but could blind you.
Between 30 PHz and 30 EHz (30,000 PHz) you'd create X-rays, which we could be used to take pictures of your bones.
And passed that you'd create gamma rays.

Electromagnetic Spectrum

So radio waves are a small part of what we call the Elecromagnetic Spectrum¹⁹⁾, which also contains visible light and a lot of other invisible stuff:

Take a moment to look at the spectrum and see which terms you're not familiar with.

Let's now unpack some of what we just saw...

Hz

A Hertz (Hz) is a measure of how fast something vibrates. For example, the A-string of a guitar vibrates 440 times per second, so we say that it vibrates at 440 Hz. The next A (an octave higher) vibrates twice as fast at 880 Hz. The human ear can hear sounds between roughly 20 Hz and 20,000 Hz.²⁰⁾ With sound, the higher the frequency, the higher the pitch. With light, the higher the frequency, the “colder” the colour.

Electromagnetic (EM) waves and sound waves are completely different things. The only thing they have in common is that “something” oscillates, but many things oscillate so that's not saying much. Just seeing “Hz” doesn't tell you anything about what it is that's oscillating in the same way that seeing “°C” doesn't tell you anything about what it is that has temperature. “Hz” is a unit of measure, not a thing itself.

Now back to radio waves...

Without going into too much detail (yet), radio waves are created by oscillating electric currents. How many times this current oscillates per second is called the frequency, which is measured in Hz (or kHz, MHz, GHz).

The “k” (kilo), “M” (mega), or “G” (giga) that you'll often see in front of Hz is a quick way of multiplying by 1000:

1 kHz	= 1000 Hz		= 10³ Hz (1 followed by 3 zeros)
1 MHz	= 1000 kHz	= 1,000,000 Hz	= 10⁶ Hz (1 followed by 6 zeros)
1 GHz	= 1000 MHz	= 1,000,000,000 Hz	= 10⁹ Hz (1 followed by 9 zeros)

These prefixes are not only used for frequencies. You've seen them in other places before:

1 km (kilometer) = 1000 m (meter)
1 MW (megawatt) = 1,000,000 W (watt)
1 GB (gigabyte) = 1,000,000,000 B (byte)

So no matter what the unit of measure, these prefixes mean:

kilo (k) = a thousand
mega (M) = a million
giga (G) = a billion
tera (T) = a trillion

This might be a good time to mention that we also have prefixes for small units (more on this later):

milli (m) = a thousandth
micro (μ) = a millionth
nano (n) = a billionth
pico (p) = a trillionth

Now, let's take another look at the Electromagnetic Spectrum picture. You should be able to make sense of pretty much all of it:

FM radio and TV broadcasting is between 50 MHz and 1000 MHz (called VHF and UHF bands).
But some radio waves go even lower than 10⁶ Hz (or 1 MHz).
Above radio waves are Microwaves, Infrared, Visible light, UV, Xray, and Gamma-rays.

Next, let's look at where Ham radio frequencies are on that spectrum.

Ham Bands Overview

Ham radio operators are allowed to transmit on very specific slices of the Electromagnetic Spectrum depending on which qualifications we have (“Basic” or “Basic +”):

In green are VHF, UHF, SHF, and EHF bands that require only the Basic qualification.
In orange are LF, MF, and HF bands that require Basic with Honours, Basic with Morse, or Basic with Advanced qualification.
In blue are CB bands, which don't require any qualification but can only be used with unmodified CB radios at relatively low power (for reference).
In red are the AM and FM radio broadcasting bands (for reference).
In maroon are the old VHF (1-13) and UHF (14-50) TV channels.²¹⁾

Bandwidth

Although the human ear can detect sounds between 20 Hz and 20 kHz, human speech typically uses sounds between 300 Hz and 3000 Hz. Modulating these sounds (more on that later) onto a radio wave means that the radio will actually transmit over a range of frequencies that we call bandwidth. For example, using SSB, the bandwidth would be 2700 Hz (300 Hz to 3000 Hz). So a radio tuned to transmit at 3.800 MHz would actually transmit between 3.7973 MHz and 3.7997 Mhz. Using AM, the bandwidth would be 6 kHz so the transmitted frequencies would be between 3.797 MHz and 3.803 MHz.

We'll explore this in much more detail later, but for now, the important concept is that to transmit a signal, the radio must transmit over a range of frequencies, not just one single frequency. This range is called bandwidth.

In addition to only being allowed to transmit on specific frequencies, ham operators also have to make sure that they don't transmit over a greater bandwidth than allowed for the specific frequencies.

That is, there are restrictions on where we transmit on the spectrum as well as how wide the transmissions are.

This is important because different modes have different bandwidth requirements. From lowest to highest:

Mode	Required Bandwidth
CW	~300 Hz
300 Baud Packet	~600 Hz
SSB Voice	2.7 kHz
Slow Scan TV	3 kHz
AM Voice	6 kHz
FM Voice	20 kHz
Fast Scan TV	6 MHz

We'll look at that picture in more details soon, but for now, let's just point out how the AM signal is twice as wide as the SSB signal.

Certificate Qualifications Overview

There are three different qualifications: Basic, Morse, and Advanced.²²⁾

Basic requires 70% to pass, but 80% or greater gives Honours privileges.
Morse requires 5 wpm.
Advanced is a different test that requires more electronics.

Privilege	Basic	Basic with Honours or Basic + Morse 5wpm	Basic + Advanced
Frequencies above 30 MHz	Y	Y	Y
Power up to 250 W	Y	Y	Y
Frequencies below 30 MHz	N	Y	Y
Power up to 1 kW	N	N	Y
Build or Modify Radios	N	N	Y
Manage a repeater	N	N	Y
Remote Control Radios	N	N	Y

The Basic (70% ‒ 79%) certificate gives access to these frequencies:

VHF and UHF bands are local bands (more on that later). Your range could vary between 1km and 100km depending on your setup (more on that later).

The “2m band” (144 ‒ 148 MHz) is the most popular band above 30 MHz. You should make sure your first radio covers at least this band. Radios that can cover both the “2m” and the “70cm” bands are very common.

The Basic with Honours (80% or more) certificate adds access to these frequencies:

HF bands are “long range” bands. Depending on the conditions, you could talk to someone in the next town or halfway around the world.

Full Frequency List

Here is the full frequency list. Highlighted information might be on the test.

The Band name is given in meter or cm. You'll need to know them.
The Maximum Bandwidth is the maximum width of the radio signal. You'll also need to know these.
Under License,
- “B” means Basic, and
- “B+” means Basic with Honours, or Basic with Morse, or Basic with Advanced.
The Notes in the last column are really important since some bands have restrictions you need to be aware of.

	Band	Range (MHz)	Max Bandwidth	License	Notes
LF	2200m	0.1357 ‒ 0.1378	100 Hz	B +	D, 1
LF	630m	0.472 ‒ 0.479	1 kHz	B +	2
MF	160m	1.8 ‒ 2.0	6 kHz	B +
HF	80m	3.5 ‒ 4.0	6 kHz	B +
HF	60m	5.332, 5.348, 5.3515 ‒ 5.3665, 5.373, 5.405	2.8 kHz	B +	3
HF	40m	7.0 ‒ 7.3	6 kHz	B +	4
HF	30m	10.10 ‒ 10.15	1 kHz	B +	D, 5
HF	20m	14.00 ‒ 14.35	6 kHz	B +
HF	17m	18.068 ‒ 18.168	6 kHz	B +
HF	15m	21.00 ‒ 21.45	6 kHz	B +
HF	12m	24.89 ‒ 24.99	6 kHz	B +
HF	10m	28.00 ‒ 29.7	20 kHz	B +
VHF	6m	50 ‒ 54	30 kHz	B
VHF	2m	144 ‒ 148	30 kHz ^¥	B
VHF	135cm	219 ‒ 225	100 kHz	B	6
UHF	70cm	430 ‒ 450	12 MHz	B	☆
UHF	35cm	902 ‒ 928 ^§	12 MHz	B	☆
		Range (GHz)
UHF		1.24 ‒ 1.30		B	☆
UHF		2.30 ‒ 2.45 ^‡		B	☆
SHF		3.3 ‒ 3.5		B	☆
SHF		5.650 ‒ 5.925		B	☆
SHF		10.0 ‒ 10.5		B	☆
SHF		24.00 ‒ 24.05		B
SHF		24.05 ‒ 24.25		B	☆
EHF		47.0 ‒ 47.2		B	☆
EHF		76.0 ‒ 77.5		B	☆
EHF		77.5 ‒ 78.0		B
EHF		78.0 ‒ 81.0		B	☆
EHF		81.0 ‒ 81.5		B	7
EHF		122.25 ‒ 123.00		B	☆
EHF		134.0 ‒ 136.0		B
EHF		136.0 ‒ 141.0		B	☆
EHF		241.0 ‒ 248.0		B	☆
EHF		248.0 ‒ 250.0		B

^¥ Since Fast Scan TV requires 6 MHz of bandwidth, it can't be transmitted below the 70cm band.
^§ The 902 ‒ 928 MHz band may be heavily occupied by licence exempt devices, which are lower power devices that don't require a license but can't be interered with (like cordless phones)
^‡ The 2.30 ‒ 2.45 GHz band is shared with Industrial Scientific Medical (ISM) licence exempt devices.

Non-ham frequencies for comparison:

	Range (MHz)	Details
MF	0.535 ‒ 1.705	AM Radio
HF	26.965 ‒ 27.405	CB (40 channels)
VHF	54 ‒ 88	VHF TV Channels 2 ‒ 6
VHF	88 ‒ 108	FM Radio
VHF	174 ‒ 216	VHF TV Channels 7 ‒ 13
UHF	462.550 ‒ 462.725	FRS (channels 1 ‒ 7 and 15 ‒ 22)
UHF	467.5625 ‒ 467.7125	FRS (channels 8 ‒ 13)
UHF	470 ‒ 692	UHF TV Channels (14 ‒ 50)²³⁾

Name of frequency ranges:

Name	Abbreviation	Frequency Range
Very Low Frequency	VLF	3 ‒ 30 kHz
Low Frequency	LF	30 ‒ 300 kHz
Medium Frequency	MF	300 ‒ 3000 kHz
High Frequency	HF	3 ‒ 30 MHz
Very High Frequency	VHF	30 ‒ 300 MHz
Ultra High Frequency	UHF	300 ‒ 3000 MHz
Super High Frequency	SHF	3 ‒ 30 GHz
Extremely High Frequency	EHF	30 ‒ 300 GHz

Important Notes

Information quoted here was taken from ISED's RBR-4.

D	For the 2200m and 30m bands, the maximum bandwidth allowed is too narrow for phone (voice) transmissions. Therefore, only digital or CW modes are allowed.
☆	Secondary User “means that transmissions shall not cause interference nor be protected from interference from stations licensed in other services operating in that band. Operating provisions defined below are excerpts from the Canadian Table of Frequency Allocations, which is amended from time to time.” Basically, this means that the Amateur Radio Service is secondary to some other service and that we must yield the frequency when they need it. We must not cause interference to these other services, and we must accept that they have first priority and may interfere with us at anytime.
1	“Stations in the amateur service using frequencies in the band 135.7 ‒ 137.8 kHz shall not exceed a maximum radiated power of 1 W (e.i.r.p.) and shall not cause harmful interference to stations of the radionavigation service.” This is the 2200m band referred to in Note D. It is mostly used for experimental purposes and transmissions must be at very low power and can't cause interference.
2	“The maximum equivalent isotropically radiated power (e.i.r.p.) of stations in the amateur service using frequencies in the band 472-479 kHz shall not exceed 1 W. Administrations may increase this limit of e.i.r.p. to 5 W in portions of their territory which are at a distance of over 800 km from the borders of Algeria, Saudi Arabia, Azerbaijan, Bahrain, Belarus, China, Comoros, Djibouti, Egypt, United Arab Emirates, the Russian Federation, Iran (Islamic Republic of), Iraq, Jordan, Kazakhstan, Kuwait, Lebanon, Libya, Morocco, Mauritania, Oman, Uzbekistan, Qatar, Syrian Arab Republic, Kyrgyzstan, Somalia, Sudan, Tunisia, Ukraine and Yemen. In this frequency band, stations in the amateur service shall not cause harmful interference to, or claim protection from, stations of the aeronautical radionavigation service. (WRC-12)”
3	“Amateur service operators may transmit in the frequency band 5351.5 ‒ 5366.5 kHz and on the following four centre frequencies: 5332 kHz, 5348 kHz, 5373 kHz and 5405 kHz. Amateur stations are allowed to operate with a maximum effective radiated power of 100 W PEP in each channel and are restricted to the following emission modes and designators: telephony (2K80J3E), data (2K80J2D), RTTY (60H0J2B) and CW (150HA1A). Transmissions in any channel may not occupy a bandwidth of more than 2.8 kHz. Such use is not in accordance with international frequency allocations. Canadian amateur operations shall not cause interference to fixed and mobile operations in Canada or in other countries and, if such interference occurs, the amateur service may be required to cease operations. The amateur service in Canada may not claim protection from interference by the fixed and mobile operations of other countries.” Other amateurs around the world do not have permission to transmit on these frequencies so Canadian amateurs are secondary users, which mean that they must stop transmitting if they interfere with other users.
4	“The use of the band 7.200 ‒ 7.300 MHz in Region 2 (North America) by the amateur service shall not impose constraints on the broadcasting service intended for use within Region 1 and Region 3 (Europe and Asia).” Although Amateurs are allowed to transmit between 7.200 ‒ 7.300 MHz in North America, they'll have to work around foreign broadcasting stations who also use this section of the spectrum.
5	“The use of the band 10.100 ‒ 10.150 MHz by the amateur service in Canada is not in accordance with the international frequency allocations. Canadian amateur operations shall not cause interference to fixed service operations of other administrations and if such interference should occur, the amateur service may be required to cease operations. The amateur service in Canada may not claim protection from interference by the fixed service operations of other administrations.” Other amateurs around the world do not have permission to transmit on these frequencies so Canadian amateurs are secondary users, which mean that they must stop transmitting if they interfere with other users.
6	“In the band 219 ‒ 220 MHz, the amateur service is permitted on a secondary basis. In the band 220 ‒ 222 MHz, the amateur service may be permitted in exceptional circumstances on a secondary basis to assist in disaster relief efforts.”
7	“The 81.0 ‒ 81.5 GHz band is also allocated to the amateur and amateur-satellite services on a secondary basis.”

Questions

B-001-003-001
B-001-004-002
B-001-004-004 → B-001-004-006
B-001-005-002
B-001-006-005 → B-001-006-006
B-001-008-004 → B-001-008-006
B-001-010-003 → B-001-010-004
B-001-010-007 → B-001-010-008
B-001-010-010 → B-001-010-011
B-001-015-001 → B-001-016-011
B-001-018-004
B-001-020-004

¹⁷⁾

Photo by Bryan Costin licensed under CC By-Nc-Sa 2.0

¹⁸⁾

As we'll see later, the “antenna” would also get smaller, the higher the frequency. So you can think of the rods and cones in your eyes as antennas tuned to the colours we can see.

¹⁹⁾

Picture of the Electromagnetic Spectrum modified from Electromagnetic_spectrum#Boundaries

²⁰⁾

Cool side note: We can double 20 Hz about 10 times before it gets to 20,000 Hz. That means that we can hear about 10 octaves. But with visible light, if we double 400 THz (red), it goes over 790 THz (Violet), which means that we can't even see a full “octave” of light. What would it feel like to see two colours that are exactly one octave apart?

²¹⁾

Remember those? (source)

²²⁾

See RIC-3, Sec 1, p.2

²³⁾

Channel 37 (608 ‒ 614 MHz) is reserved for Radio Astronomy so there are no TV broadcasts there. See: Channel_37

non-ham

Emergency Communications for Non-Hams

Amateur radio can provide long range communication (voice or digital) in case of an emergency. But for local communication, there are options that do not require a radio license or certificate.

License-Exempt Devices

The radiofrequency spectrum is a scarce resource. In Canada, ISED regulates its use to prevent interference between different users. With respect to interference, there are two types of users:

Primary users are given priority of a frequency and are protected from interference.
Secondary users cannot interfere with primary users, and are not protected from interference.

For voice communications in Canada, CB radios and FRS radios are the two main license-exempt options. However, from ISED FAQ #6:

It is illegal for consumers to import radio devices into Canada that do not bear a label with an Industry Canada certification/registration number.

License-exempt radios are secondary users.

Baofeng radios and the likes are illegal to use without the appropriate certificate.

Check if a certification/registration number is valid.

FRS

For voice, using an FRS radio is the most practical option.

Channels

There are 22 channels in the 462 and 467 MHz band:

Ch.	Frequency (MHz)	Max Power	Ch.	Frequency (MHz)	Max Power	Ch.	Frequency (MHz)	Max Power
1	462.5625	2 W	8	467.5625	0.5 W	15	462.5500	2 W
2	462.5875	2 W	9	467.5625	0.5 W	16	462.5750	2 W
3	462.6125	2 W	10	467.5875	0.5 W	17	462.6000	2 W
4	462.6375	2 W	11	467.6125	0.5 W	18	462.6250	2 W
5	462.6625	2 W	12	467.6375	0.5 W	19	462.6500	2 W
6	462.6875	2 W	13	467.6625	0.5 W	20	462.6750	2 W
7	462.7125	2 W	14	467.7125	0.5 W	21	462.7000	2 W
						22	462.7250	2 W

In Canada, repeater and high-power operations are not permitted, where as in the US, they are with a GMRS license.

In the US, Channels 15 ‒ 22 are shared with licensed GMRS radios.

Each frequency has the same channel number regardless of the device brand.

CTCSS/DCS

To help quiet (squelch) unwanted signals, FRS radios have the option of transmitting a CTCSS tone or DCS code (AKA: “PL tones”, or “sub-audible tones”). These are low “bass notes” or digital information that the radio transmits on top of the voice, but which can't really be heard. If the receiver is configured to expect a specific tone/code, it will keep the speaker squelched unless that tone/code is detected. This is useful to ignore chatter from others on a busy channel, but if two radios with different tones transmit at the same time on the same channel, they will interfere with one another.

K0TFU has a really good article explaining all of this for FRS radios: FRS/GMRS Privacy Codes Demystified, and our own site goes a little deeper in the context of ham radios.

Different brands of radios use different numbers to represent different tones/codes.

By default (and especially in an emergency situation), CTCSS/DCS should be disabled so that your radio can hear everyone.

Choosing a Radio

Here are three restrictions that preclude Baofeng radios from operating on FRS frequencies. From ISED, RSS-210, Annex E:

The antenna of FRS devices shall be an integral part of the unit.

FRS/GMRS devices shall not:

be designed to interconnect to public switched telephone networks

be designed to transmit data in store-and-forward packet operation mode

incorporate one or more scrambling features (e.g. encryption, voice inversion, obscuring)

All frequency determining circuitry, including crystals and programming controls, shall be internal to the transmitter and made inaccessible to the user from the exterior of the device.

FRS radios cannot be connected to a better antenna to extend the range, or be able to transmit on non-FRS frequencies.

There are a lot of “toy” FRS radios out there, so a good radio will tend to be a bit more expensive. The typical range could be anywhere from 1 km to 10 km depending on the terrain and elevation, but should not vary much from radio to radio. Here's a good explanation of what affects range in the context of ham radio.

Here's a short list of good radios at every price point:

The Rocky Talkie Mountain Radio is $220 USD each.
The Backcountry Access BC Link 2.0 is $206 USD each.
The Retevis RB48 is $115 CAD for a pair.
The Midland T10 is $30 USD for a pair.

See the Wirecutter site for reviews and a list of what to avoid.

First Use Setup

Refer to the user manual for specific instructions, but in general, you should:

Disable the CTCSS/DCS on all 22 channels. On the Revetis RB48, the CTCSS/DCS is represented by a number between 1 and 121 (on the right). The number 0 means that CTCSS or DCS is disabled.
Disable the Roger Beep, which is short chirp that's transmitted when you let go of the PTT button to indicate that you're done talking. It can be pretty annoying for others.
Disable VOX, which is an option to transmit without pressing the PTT.

MeshCore

From Wikipedia:

MeshCore is an open-source mesh networking protocol and software platform designed for off-grid, low-power text communication using LoRa (Long Range) radio technology. The system enables decentralized, multi-hop wireless messaging without reliance on cellular networks or internet infrastructure.

Use cases include emergency and disaster communications, outdoor and remote activities, [...] and experimental and educational deployments of low-power mesh networking.

[It] is designed to [...] operate in unlicensed ISM frequency bands such as 868 MHz and 915 MHz, depending on regional regulations.

The basic idea is that you get a small companion device that you pair to your cell phone via bluetooth, and via that device, you can text others or post public messages using the 915 MHz band, all without a special license.

See this page for more information on how to get started.

The current network reaches from Parkville to Victoria to Abbotsford.

home

Meshcore

Introduction

From Wikipedia:

MeshCore is an open-source mesh networking protocol and software platform designed for off-grid, low-power text communication using LoRa (Long Range) radio technology. The system enables decentralized, multi-hop wireless messaging without reliance on cellular networks or internet infrastructure.

Use cases include emergency and disaster communications, outdoor and remote activities, [...] and experimental and educational deployments of low-power mesh networking.

[It] is designed to [...] operate in unlicensed ISM frequency bands such as 868 MHz and 915 MHz, depending on regional regulations.

Getting Started

Get a companion device like:
- the Wio Tracker L1 Pro from seeed studio or from Robot Shop
- : add other options here
Flash the device with the latest Meshcore Firmware (using a chromium browser).
Install the Meshcore app on your phone. (Android, iOS, Web App, NodeJS, Python)
Pair the device with your phone.
Turn off Auto-Add Contacts

See Scott Baker's article for more information.

More Advanced

Install a repeater like the SenseCAP Solar Node P1-Pro from seeed studio or RobotShop
Use an antenna like this one, this one or one of these.
Install sensors.

Maps

Tools

Resources

List of Repeaters on the Coast

VA7KRZ-Gibsons-RP1

Location:	Kitchen Window, Gibsons (49.414161, -123.515539)
Equipment:	Heltec V3 with a 5.8 dBi Antenna
Orientation:	Clear line-of-sight toward Richmond / Lower Mainland
Sponsor:	Adam, VA7KRZ
Public Key:	612826cd886fd45bc6ce607308d14a4cb77b49673042d9844bf54242df5e74d8

Under Construction:

Location:	Roof, Gibsons (49.414161, -123.515539)
Equipment:	RAK19004 (power module), RAK19007 (Baseboard), RAK4631 (LoRaWAN module)

VA7FI - SenseCap

Location:	Atop a 20 m tree in Roberts Creek
Equipment:	SenseCAP with stock antenna
Sponsor:	Patrick, VA7FI
Public Key:	0c035f5ec37944b7f7df9599cf2b74fd8b75851481dda4aac0c813854fca1726

VA7XES - Roberts Creek

Location:	Roberts Creek (49.449751, -123.653155)
Equipment:
Sponsor:
Public Key:	857d939db34d0afdeb7cb6ee4cddfc59aab02dc6efd1e76d14fc318e4e54c1e2

Sechelt_PBay

Location:
Equipment:
Sponsor:	Gary, VA7GYT
Public Key:	d7ed6f8f764ca63a4158108d3a24fde6e8df836b6f63aa09ef2a2060b0bd304f

SSAC-1

Location:	On roof of Sechelt Senior Activity Centre (49.4757, -123.7580)
Equipment:	SenseCAP Solar Node P1-Pro with : Antenna
Sponsor:	Larry, VA7LSP
Public Key:	6dfc25cb2d0a6efe8520f469d9ac2e8c5dacde42c4d380cf553dd05bf768b1e2

te-kevflex

TE-KEVFLEX

Interesting product from Australia: antenna wire with a kevlar core.

home

Articles and Links

For Aspiring Hams

Ham Basics Study Guide Under Construction
Doug Nix's Blog
Hamstudy
Practice tests
Conceptual electronics videos

For New Hams

VHF/UHF/Microwave

HF

Digital

West Coast AREDN
Meshcore
Signalink
- Winlink Express
- Packet (place holder for future)
- APRS on Windows
- SSIDs for Winlink vs APRS
- Digital Concepts
IC-7300
Slow Scan TV

ISED Links

Amateur Radio Groups and Services

Amateur Radio Associations

Amateur Radio Equipment Retailers

Burnaby Radio (Burnaby)
Fleetwood Digital (Surrey)
CanaKit (North Vancouver)
GPS Central (Alberta)
Radioworld (Ontario)
Maple Leaf Communications (Ontario)
DX Canada (Online from Canada)
DX Engineering (USA)
Ham Radio Outlet (USA)
R&L Electronics (USA)
Powerwerx (USA)
Gigaparts (on eBay)

Used:

Amateur Radio Equipment Manufacturers

Radios:

Antennas:

Comprod

Accessories:

West Mountain Radio (USA)
Timewave Technology

Commercial Frequencies

Canadian Spectrum Management System Data (Formerly known as TAFL)
- Search the TAFL
- TAFL Map (118 MHz - 525 MHz in Sechelt. Click New in green box on top left to change)
RadioReference
BC Forest Service Frequencies

RFI

Maps And Weather

Misc

This Website

Editing this site.
- Link, View, and Create PDFs
- Wrap Plugin Examples
Online html editor to create fancy stuff

emergency_communication_for_non-hams

Emergency Communication for Non-Hams

I just created a new page outlining two tools (FRS and Meshcore) that non-amateur radio operators can use to stay connected with their local groups in case of an emergency. To navigate there from the home page: Emergency → SCEC page → FRS and Meshcore.

Any club member should feel free to edit the page as needed!

scec

Sunshine Coast Emergency Communications

PDFs To Print

An up-to-date copy of this page
A few copies of the radiogram from PERCS.
BCARCC repeater frequencies for Lower Mainland & Coast and Vancouver Island
and/or this amalgamated spreadsheet list.

Non-Amateur radio operators can use FRS and Meshcore to communicate locally.

Initial Actions in the Event of an Emergency

In the event of a significant emergency affecting communications across the Sunshine Coast, all amateur radio operators should:

Monitor the VE7RXZ repeater on VHF 147.220 MHz +0.6 T100.0 for traffic or requests for assistance from VE7SCE.
If VE7RXZ is not operational, monitor 147.220 with 100Hz tone (without any offset) (Net controllers monitor 147.820 for operators that are operating in duplex and let them know to go to simplex on 147.220 T100.0)
If able, also monitor VE7SCK 442.650 +5.0 T100.0.
If VE7SCK is not operational, monitor 442.650 with 100Hz tone (without any offset) (Net controllers monitor 447.650 for operators that are operating in duplex and let them know to go to simplex on 442.650 T100.0)
If able, also monitor simplex VHF: 1: 146.430 MHz, 2: 147.540 MHz, 3: 146.490 MHz, 146.565 MHz for traffic or request for assistance from VE7SCE.
If able, monitor EMBC HF frequencies for information (see below).

It is unlikely that VE7SCE will use HF for local communications on the Sunshine Coast, however relays may be required for another station on frequency and operators should monitor EMBC or BCPSN HF frequencies if able to do so.

Declaration of State of Emergency by the SCRD EOC

The following will be broadcast from VE7SCE on VE7RXZ 147.220 MHz +0.6 T100.0 and/or on simplex frequencies:

Taking Control of the Net

ALL STATIONS, ALL STATIONS, ALL STATIONS:
This is VE7SCE – Sunshine Coast Regional District Emergency Operations Centre, Sechelt, British Columbia.^†
A [LOCAL / REGIONAL / PROVINCIAL] State of Emergency has been declared, I say again:
a [LOCAL / REGIONAL / PROVINCIAL] State of Emergency has been declared.
This frequency is now in use by the SCRD Emergency Operations Centre - VE7SCE - all stations not having emergency traffic are requested to remain clear.
If you have traffic concerning safety of life or property in the Sunshine Coast Regional District, and you are unable to contact 911, relay your traffic to this station.
Otherwise, if it is safe to do so, all station operators within the SCRD region are requested to remain monitoring this frequency as your assistance may be requested.
This is VE7SCE, SCRD EOC Net Control monitoring...

Taking Check ins

ALL STATIONS, ALL STATIONS, AL STATIONS:
This is VE7SCE – Sunshine Coast Regional District Emergency Operations Centre, Sechelt, British Columbia.^†
Stations within the SCRD region are requested to check in now with your callsign, name and location.
Once checked in you must inform SCRD Net Control if you intend to leave the frequency.
This is VE7SCE standing by ...

^† As we share a frequency with W7AVM on Whidbey Island in Washington State, the full SCRD name and location will be used initially to avoid any confusion should our traffic be heard south of the border.

HF Emergency Frequencies

Sources: http://www.percs.bc.ca/ and https://www.rac.ca/ : find exact pages to link to.

Description	Frequency [MHz]	Mode
EMBC 80m Primary Night	3.735	LSB Phone
EMBC 80m Secondary Night	3.745	LSB Phone
EMBC 40m Primary Day	7.060	LSB Phone
EMBC 40m Secondary Day	7.070	LSB Phone
EMBC DATA	3.613.50	USB DATA
EMBC DATA	7.089.50	USB DATA
VE7SWF South West EMBC PREOC	14.135	USB Phone
VE7SWF South West EMBC PREOC	21.120	USB Phone
VE7KAZ Kamloops EMBC PREOC RMS	5.371.50	USB DATA^‡
VE7RBH Smithers, BC Winlink RMS	3.623.50 / 7.063	USB DATA^‡
WASHST 01 Washington State	3.985	LSB Phone
WASHST 02 Washington State	3.994	LSB Phone
WASHST 03 Washington State	7.245	LSB Phone
BCPSN: BC Public Service Net	3.729	LSB Phone
ALASKA Emergency Net	14.292	USB Phone
EMCOM A	3.675	LSB Phone
EMCOM B	7.135	LSB Phone
EMCOM C	14.135	USB Phone
EMCOM D	18.135	USB Phone
EMCOM E	21.235	USB Phone
EMCOM F	28.235	USB Phone
OREGON	3.980	LSB Phone

EMBC: Emergency Management BC Frequencies
WASHST: Washington State Emergency Frequencies
EMCOM: IARU / RAC Canadian Emergency Frequencies
OREGON: Oregon State Emergency Net Frequency
^‡Winlink RMS Station

National HF Emergency Communications Frequencies

Source: RAC

The following frequencies and modes have been pre-determined for suggested use of the Amateur Radio Emergency Service during a declared emergency, or a disaster declared or otherwise, occurring anywhere in Canada. These frequencies have been registered with the International Amateur Radio Union (IARU) for its listings of Canadian national emergency frequencies in IARU Region 2.

These are suggested frequencies and should not be construed as meaning that other HF frequencies may not be considered for Emcomm operations.

No Amateur Radio operator or group has exclusive ownership of any particular frequency on any band and, while common sense and courtesy logically would dictate that other Radio Amateurs should keep clear of frequencies being used for emergency or disaster operations, the affected ARES Net Control Station (NCS) must be prepared to move up or down from the pre-determined frequency, as required, in order to conduct operations. Entering into an on-air argument must be avoided.

	Single Sideband		CW		Digital
Band	Frequency	Tactical	Frequency	Tactical	Frequency	Tactical
80 M	3.675 MHz LSB	Alfa	3.535 MHz	Golf	3.596 MHz	Mike
40 M	7.135 MHz LSB	Bravo	7.035 MHz	Hotel	7.096 MHz	November
20 M	14.135 MHz USB	Charlie	14.035 MHz	India	14.096 MHz	Oscar
17 M	18.135 MHz USB	Delta	18.075 MHz	Juliet	18.096 MHz	Papa
15 M	21.235 MHz USB	Echo	21.035 MHz	Kilo	21.096 MHz	Quebec
10 M	28.235 MHz USB	Foxtrot	28.035 MHz	Lima	28.096 MHz	Romeo

Other Frequencies

Repeater Book: The phone app is also highly recommended.
Canadian Spectrum Management System Data (Formerly known as TAFL)
- Search the TAFL
- TAFL Map (118 MHz - 525 MHz in Sechelt. Click New in green box on top left to change)
RadioReference

Regular Emergency Nets

Net	Day	Time	Frequency
Alaska Emergency Net	Mon ‒ Fri	09:30 LT	14.292 MHz
Canadian Red Cross Net	Sundays	11:00 PST noon PDT	14.125 MHz
BC Public Service Net	Daily	17:30 PST 18:30 PDT	3.729 MHz
VE7PEP Simplex ^α	Wednesdays	18:30 ‒ 19:10 LT	147.570 MHz
PERCS HF ^β	Wednesdays	18:45 LT	3.735 MHz followed by 7.275 MHz
VE7PEP ITS ^δ	Wednesdays	19:15 ‒ 19:40 LT	Island Trunk System
VE7SWF VHF	3^rd Wednesday	19:30 LT	VE7RPT repeater (146.940 -)
BC and Yukon NTS Net	Daily	19:30 LT	3.716 MHz

^α The purpose of the net is to make contact with EOCs in the Capital Regional District.

^β The net is held every Wednesday at 18:45 on 3.735 MHz LSB. Then at 19:00 we move to 7.275 MHz LSB. Net control on 1^st, 3^rd and 5^th Wednesday is VE7SWF (South West PREOC) and on 2^nd and 4^th Wednesday is VE7PEP (Vancouver Island PREOC).

^δ The purpose of the net is to make contact with EOCs and interested amateurs in the Vancouver Island Region. Each of the Regional Districts are called in sequence.

Island Trunk System

City	Callsign	Frequency	Offset	Tone
Newcastle Ridge	VE7RNC	146.700	−	141.3
→ Port McNeill	VE7RNI	146.940	−
→ Woss Lake	VE7RWV	146.880	−
→ Campbell River	VE7RVR	146.820	−
→ Mt. Washington	VE7NIR	443.700	+	141.3

Lost Lake	VA7DJA	145.430	−	141.3
→ Ucluelet	VE7PRT	147.200		141.3
→ Mt. Benson	VA7ITS	444.725	+	141.3
→ Mt. Brenton	VE7AQW	146.680	−	141.3
→ Mt. Brenton	VE7AQW	442.600	+	141.3
→ Victoria	VE7RAA	443.575	+	136.5

The trunk has two main interconnected nodes: Sayward, and Lost Lake. The other repeaters are connected to either one of these two nodes.²⁴⁾

Source: islandtrunksystem.org

SCEP Details

Source: SCRD ECT/SCRD EOC Communications Diagram/

VE7SCE Radio Stations

Data/Comms Position 1	Kenwood TM-D710GA VHF/UHF
Data/Comms Position 2	Kenwood TM-D710GA VHF/UHF
Comms/Pactor Position 1	Kenwood TM-D710GA VHF/UHF Kenwood TS480HX 200W HF SCS DR7400 Pactor LDG 200 PRO II Auto Antenna Tuner
Comms/Data Position 2	Kenwood TM-D710GA VHF/UHF
SCRD Trunk Radio	Installed on Buses/SCRD Service & Parks Vehicles. Repeater on Mt. Benson & VE7RXZ as SCA 147.220 MHz is programmed into all SCRD Trunk radio SCEP 6 is the dedicated Emergency Program channel

Inter-Municipal Emergency Radio System via Bowen Island 2C repeater
Health Emergency Management BC - Emergency Radio to VGH and Sechelt Hospital
Emergency Fire Dispatch system for Sunshine Coast Fire Departments
Marine and Aero Radio

Contact Information

Sources: EMBC, PERCS SWR, PERCS VIR

SCEP:
- Callsign: VE7SCE
- 1975 Field Road, Sechelt (entrance on Solar Road)
- https://www.scrd.ca/Emergency-Program, https://www.scrd.ca/Emergency-Radio
- Tel: 604-885-6887
- email: emergency.program@scrd.ca
- Winlink: ve7sce@winlink.org

EMBC South West Region (our region)
- Callsign: VE7SWF
- 14292 Green Timbers Way, Surrey, B.C. V3T 0J4
- Tel: 604-586-4390
- Fax: 604-586-4334
- email: EMBC.SWEAdmin@gov.bc.ca
- Winlink: ve7swf@winlink.org

EMBC Vancouver Island Region (for reference only)
- Callsign: VE7PEP
- Block A - Suite 200, 2261 Keating Cross Road, Saanichton B.C., V8M 2A5
- Tel: 250-952-5571 or 250-952-5572 (old?: 250-952-5848)
- Fax: 250-952-4304
- email: EMBC.VIRAdmin@gov.bc.ca
- Winlink: ve7pep@winlink.org

Emergency Preparedness

Sources: PreparedBC, getprepared.gc.ca

Basic emergency kit

Water: At least two litres of water per person per day; include small bottles that can be carried easily in case of an evacuation order
Food that won't spoil, such as canned food, energy bars and dried foods (replace food and water once a year)
Manual can-opener
Crank or battery-powered flashlight (and extra batteries). Replace batteries once a year.
Crank, battery-powered radio (and extra batteries) or Weatheradio
First aid kit
Extra keys to your car and house
Some cash in smaller bills, such as $10 bills and change for payphones
A copy of your emergency plan and contact information
If applicable, other items such as prescription medication, infant formula, equipment for people with disabilities, or food, water and medication for your pets or service animal (personalize according to your needs)

Recommended additional items

Two additional litres of water per person per day for cooking and cleaning
Candles and matches or lighter (place candles in deep, sturdy containers and do not burn unattended)
Change of clothing and footwear for each household member
Sleeping bag or warm blanket for each household member
Toiletries
Hand sanitizer
Utensils
Garbage bags
Toilet paper
Water purifying tablets
Basic tools (hammer, pliers, wrench, screwdrivers, work gloves, dust mask, pocket knife)
A whistle (in case you need to attract attention)
Duct tape (to tape up windows, doors, air vents, etc.)

²⁴⁾

Flowchart of ITS created using draw.io (aka diagrams.net) with:

Lost Lake VA7DJA 145.430− 141.3->UHF link->Mt Brenton VE7AQW 146.680− 141.3 442.600+ 141.3
Lost Lake VA7DJA 145.430− 141.3->UHF link->Mt Benson VA7ITS 444.725+ 141.3 
Lost Lake VA7DJA 145.430− 141.3->IP link->Ucluelet VE7PRT 147.200 141.3
Lost Lake VA7DJA 145.430− 141.3->RF link->Saltspring Relay
Saltspring Relay->RF link->Victoria VE7RAA 443.575+ 136.5
Newcastle Ridge VE7RNC 146.700− 141.3->220 link->Lost Lake VA7DJA 145.430− 141.3
Newcastle Ridge VE7RNC 146.700− 141.3->UHF link->Mt Washington VE7NIR 443.700+ 141.3
Newcastle Ridge VE7RNC 146.700− 141.3->220 link->Campbell River VE7RVR 146.820− 141.3
Newcastle Ridge VE7RNC 146.700− 141.3->220 link->Woss Lake VE7RWV 146.880−
Newcastle Ridge VE7RNC 146.700− 141.3->220 LINK->Port McNeill Airport Relay
Port McNeill Airport Relay->UHF LINK->Port McNeill VE7RNI 146.940−

ised_radio_equipment_list

ISED Radio Equipment List

According to the ISED website:

It is illegal for consumers to import radio devices into Canada that do not bear a label with an Industry Canada certification/registration number.

Here's how to check for that certification/registration number, and make sure it's real.

Find the tag located underneath the radio or underneath the battery. Here are three examples:

Icom IC-7300 HF Radio	Quansheng UV-K5 VHF/UHF Handheld	Retevis RB48 FRS Radio

Look for the number that starts with IC (underneath the FCC ID number).
Use ISED's Radio Equipment Search tool to look up those numbers in the Certification Number field.

At first glance, it looks like all three of these radios are certified by ISED, but that's a bit surprising since the Quansheng UV-K5 radio is one of those VHF/UHF radios that can transmit on its entire bands. Here are the results from ISED's search tool for each:

Searching for 202D-376500 yields:

Searching for 27919-RB48 yields:

But searching for 30518-UVK5 did not return a result, and broadening the search to just 30518 returns a wifi enabled LED light:

It's hard to be 100% sure, but it looks like the IC certification/registration number for the UV-5K might be fake, which again, makes sense since this radio can transmit on its entire bands.

savvy_2-element_pota_antenna

Savvy 2-Element POTA antenna

From Larry (VA7LSP):

Instructions from printables.com

rattlegram_desktop

Rattlegram Desktop

A few years ago, I posted about Rattlegram, a mobile app that encodes and decodes text as audio. I started playing with it again a bit today and found that someone made a desktop version. It works the same on the computer as it does on the phone. I briefly tried to connected my computer to the HF radio via USB but it wouldn't transmit. If anyone figures out how to do that, please comment below!

aioc_all-in-one-cable

AIOC (All-in-one-Cable)

From https://lectronz.com:

The AIOC is a small adapter with a USB-C connector that enumerates itself as a sound-card (e.g. for APRS purposes), a virtual tty (“COM Port”) for programming and asserting the PTT (Push-To-Talk) as well as a CM108 compatible HID endpoint for CM108-style PTT (new in firmware version 1.2.0).

The AIOC is Open-Source Hardware designed by Simon Küppers.

getting_started_with_freedv

Getting Started with FreeDV

A few months ago, I posted about FreeDV without knowing much about it. A few weeks ago, I found this comprehensive guide by VU3DXR.

I'm gonna put this on my ham radio to-do list...

tx-500mp_and_link500mp_tnc

TX-500MP and LiNK500MP TNC

The TX-500MP by Lab599 is a portable / handheld HF transceiver. Recently, DiY599, an after market company, created the LiNK500MP TNC, which fits on top of the radio and adds digital and CAT capability to the radio wirelessly.

discovery_drive_for_the_discovery_dish

Discovery Drive for the Discovery Dish

There's an interesting crowdfunding project on https://www.crowdsupply.com for:

[...] a low-cost, turnkey, fully weatherproof, high-quality automatic Az/El (azimuth/elevation) antenna rotator designed for use with Discovery Dish and other antennas of similar size and weight, such as Yagi and Wi-Fi grid antennas.

A motorized rotator allows you to use a satellite dish or directional antenna to track and receive signals from polar orbiting satellites, which quickly move across the sky. It also lets you switch swiftly between geostationary satellites without manually realigning the dish. It’s also very easy to set up—no fiddling with expensive, separate controllers! Just connect Discovery Drive to 12V and Wi-Fi (or USB serial) and go!

It's priced at $699 US and funding ends on Apr 23, 2026 at 04:59 PM PDT. That could be an interesting solution (though probably overkill) for an AREDN dish.

Sun Coast Amateur Radio Club Society

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