Ghost Channel & Gains

[lunderhage]

I am running SDR++ built from master recently together with a RTL-SDRv3 dongle and an aviation antenna.

When I am listening to a certain radio channel, in this case 120.155 (AM, 15khz) with a 1.024 wide spectrum, I hear 122.45 at the same time. How is that even possible? It does not happens in SDRTouch on my phone with similar settings.

Some transmissions come in very strong and it is impossible to hear what they say when using AGC (RTL+Tuner). However, when those are turned off, I can barely here anything at all.

Do you have any hints?