FT8 Transmit Signals on 12 Meters and 160 Meters

Mark Griffin

Guy,

Please look at the following pictures for my Transmit Signal on both 12 Meters and 160 Meters. The only difference is that with the 160 Meter Signal I am using my Receive Antenna versus the Transmit Antenna for receive on 12 meters.

Am I getting some time of RF or something that would cause the 160 Meter transmit signal to be so different?

Mark KB3Z

johnn1jm

Have you tried to reduce your transmit DAX? I'm not sure looking at your transmit signal that way is an accurate representation of the signal.

Mark Griffin

I will have to try that and see what happens.

Mark KB3Z

Geoff AB6BT

Are the scales on the right side of the window the same? You don't show them in your photos.

Mark Griffin

I will have to take a look at the Geoff!

Mike-VA3MW

That is 'fake news' so to speak. :)

Your RX antenna RXA and that is external to band pass filters. This is normal.

John KB4DU

This a common confusion point. Part of it is that the pan pick up “bleedover” from the transmitter to display. The displayed signal is before the final filtering. The actual transmission doesn’t have all those peaks.

Ken Wells

The OP's Pictures did not show the full screen, so it is impossible to tell how much RF Preamp is applied on 160 Meters. Nor what the setting for WNB is. Both of these settings can affect the "bleedover" issue on the panadapter while transmitting.

In any case, anything outside the normal TX Filter bandwidth is only "Phantom" signals on the panadapter, which are filtered out before hitting the actual transmit amp and antenna.