[TenTec] Receiver Specs

[w.marty.ray]

Hi, Jim.

Thanks for the nice explanation. I really finally 'got it' when you talked about the actual dBm. I now know that if I am trying to receive a weak signal on 160m, and a S9+60 (-13dBm) signal is on an adjacent frequency, I will be able to hear a signal near the MDS of my Omni VI+ (at 5kHz). (Yeah, but what about the rock crusher that is only 750Hz away?...guess I need to measure it...)

Anyway, the reason I responded is to ask you to elaborate on the IMD. Can you explain IMD in terms of dBm? If I have a receiver spec of, say, +20dB IP3, and an IMD3 of 100dB, what does that mean in terms of actual signals? Can you explain using my real world 160m example. Let's say two S9+60dB signals mixing into my passband. How strong would the resulting spurious signal be?

Thanks!

Marty Ray, N9SE