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--- hambasics:sections:wavemodulation [2026/04/01 20:09] – [Amplitude, Wavelength, Frequency, and Period] va7fi
+++ hambasics:sections:wavemodulation [2026/04/01 20:47] (current) – [FM] va7fi
@@ Line 37: / Line 37: @@
 </WRAP>
-Note that the reason we're using just 300, instead of 300,000,000 is that we've cancelled 6 of the zeros so that the frequency is in MHz instead of in Hz.
+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?
@@ Line 69: / Line 69: @@
 Modulation is the process of "encoding" a message (be it voice or digital) onto a radio wave.
-{{ youtube>D9Oa6jaHwtA }}
+===== 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:
+    - How does the quality of the audio change?
+    - 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:
+    - How does the quality of the audio change?
+    - How far can you go before you can't understand the audio anymore?
@@ Line 203: / Line 210: @@
 {{  fm02.png  }}
-Here, the math is a bit more involved and requires at least 1<sup>st</sup> 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:
+Here, the math is a bit more involved and requires at least 1<sup>st</sup> 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:
 <WRAP centeralign>