Hi Al,
Thanks for the feedback, and I get that, but the issue seems too consistent. I can transmit into an antenna or dummy load, 1/2 watt or 5 watt, and it still happens. I can tune the 2M side up and the 70cm product goes up with it. Also, I don't have any local source like that. It's actually pretty quiet here. I use an SDR on a attic dipole and I don't have interference issues with that. But your point about how a 2M LPF isn't knocking it down is well taken. Could it be coming from the 817 mixer?
Here is a pic of the 817 in transmit and and the display on the 705. Both rigs in FM. 817 fed with sine wave audio and triggering the VOX.
Pete N1QDQ
N1QDQ