I was on 40m #JS8Call when OH8STN sent Heartbeat message from few kilometers away. It was overwhelming my RX and I managed to catch a screenshot.
His message was sent on frequency 889Hz, but we can also see signal harmonic on 1778Hz (2 * 889Hz) and 2667Hz (3 * 889Hz).
Also notice how the width doubles on 2nd harmonic (1778Hz) and triples on 3rd harmonic (2667Hz).
Maybe this doesn't have any other point, but to show how harmonics look like on waterfall.
@M0YNG Indeed! It took me a while to understand what's happening. What I don't know if why is it happening.
From these little things we can learn and build our knowledge.
I had my rig's RF gain up. Lowering gain down removed the harmonics. So this phenomenon was purely on my RX side.
This is a screenshot of me lowering the RF gain in middle of heartbeat transmission. See how the harmonics just disappear while original signal still continues on it's frequency.
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