Harmonics.

I was on 40m 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.

@oh8hub that's really interesting! I've never seen the spread so clearly shown too.

@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.

@oh8hub @M0YNG What once was a great weak signal mode is being destroyed by people running way too much power and improper drive levels. I cringe when I see Eb/N0 numbers like +25dB while stations copy my -25 dB QRPp. My best was Japan on 15 meters with 100mW

@W8HF @oh8hub well it is weak signal, not low power...

I have to admit that I may have been running ft8 at 100w. I thought the tx audio level on my signalink would reduce the output power, but it doesn't seem to make any difference.

@M0YNG @oh8hub My advise. If you routinely get reports over 0dB, you are running too much. At my old QTH I never ran over 5W but I had a nice antenna system. It is more important that the signal is clean.

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@W8HF I don't seem to get many reports over 0, but you are welcome to look at my log and make suggestions :)

log.m0yng.uk/index.php/logbook

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@M0YNG That looks fine. A better metric for too much power would be seeing very lopsided reports like sent -23 received +10 😂. Sometimes band conditions are great and even a tin whistle signal gets a great report.

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