[hpsdr] Boat Anchors..PreAmps

[lstoskopf at cox.net]

If you look at OLD navy receivers you will often find two stages of RF amps before the mixer with a complex RF filter system.  More than weak signals would require in the bands then used or need for strong signal rejection.  Today's ships do have real problems with multiple signals though.  A lot of that stuff was to prevent LO leakage which might give the ship's position away.  The late W0CY here had several of those and they were magnificent mechanical devices with lots and lots of shielding and DC bypassing.

In the case of our ADC's, a very valid purpose of the pre-amp is to protect the input from excess voltages.  I've blown two on a different RX using the same ADC (lightning once and a leaky TR relay the other).

I'm pretty sure that our ADC is a voltage driven device.  Perhaps someone can explain whether we are looking at overload from the highest voltage in the band or total power across the band (input).  Or am I back to the dB power vs dB voltage bit?

N0UU