howto:hambasics:sections:practice
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howto:hambasics:sections:practice [2020/10/24 16:54] – [Selectivity] va7fi | howto:hambasics:sections:practice [2020/12/30 09:08] (current) – va7fi | ||
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==== Filters ==== | ==== Filters ==== | ||
Sometimes a specific noise or interference is mixed in the signal and we'd like to reduce or eliminate it. One way is to use filters. | Sometimes a specific noise or interference is mixed in the signal and we'd like to reduce or eliminate it. One way is to use filters. | ||
- | * A filter that lets high frequencies through but blocks low frequencies is called a high pass filter. | + | * A filter that lets high frequencies through but blocks low frequencies is called a //high pass// filter. |
- | * A filter that lets low frequencies through but blocks high frequencies is called a low pass filter. | + | * A filter that lets low frequencies through but blocks high frequencies is called a //low pass// filter. |
- | * A filter | + | |
+ | * An SSB voice signal can use a 2.4 kHz filter where as | ||
+ | | ||
+ | * The " | ||
{{ notch1a.png }} | {{ notch1a.png }} | ||
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- The frequency is 7.100 MHz on LSB. | - The frequency is 7.100 MHz on LSB. | ||
- The scope shows this frequency relative to the entire band (7.000 Mhz to 7.300 Mhz) | - The scope shows this frequency relative to the entire band (7.000 Mhz to 7.300 Mhz) | ||
- | - At the bottom is the audio spectrum of what we hear (300 Hz to 2.5 kHz) | + | - At the bottom is the audio spectrum of what we hear (with a 2.4 kHz band pass filter). |
You'll notice that there' | You'll notice that there' | ||
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===== Stability ===== | ===== Stability ===== | ||
+ | This is the ability of a receiver to stay on the right frequency and not //drift//. | ||
====== Transmitters ====== | ====== Transmitters ====== | ||
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- | ======= Questions | + | ====== Questions ====== |
* B-003-010-001 -> B-003-011-001 | * B-003-010-001 -> B-003-011-001 | ||
- | [[stationassembly |{{/ | + | [[stationassembly |{{/ |
howto/hambasics/sections/practice.1603583671.txt.gz · Last modified: 2020/10/24 16:54 by va7fi