General hint on mixing / Interference on 40m
Hello world :)
Is there a general way to calculate where mixed up interference may possible come from?
I receive sea weather report on 40m 7193 RTTY - sometimes even 3 or 4 times on 40m with 40khz in between. I know it isn't really there. I first thought it was from DDH47 on 147kHz since I receive them with -30dbm. So I build a notch for that freq. and have them down 40db now. Surprisingly I still have some mixed up signal from seaweather in the 40m band. That weather report is transmitted on different bands at the same time so now I don't have any idea how to possibly calculate where the source frequency may be.
How is the math behind that? :-)
Feel free to tune in and hear how it sounds. http://dg7lan.mooo.com:8073/?f=7151.52lsbz6