That's exactly what I was thinking. This is the preamp I use on my RX antennas: http://www.w0btu.com/W0BTU-broadband-preamps.html . It's been in service for many years and works great. Even with a 100 kHz to 30 MHZ bandwidth, and with no input attenuation, it rarely overloads and produces spurs. The few times I have seen it overload, I think it was the back-to-back 1N914 protection diodes in parallel with the input conducting. (I've since gone from just two to four diodes in series/parallel.)
Having said that, I usually use a small amount of input attenuation when I have it switched on. I just use a ~2K pot in series with the input, and adjust it so that the signal level from my Beverages are equal to the signal level from the TX antennas. I know that there are probably more advanced preamp designs now, but it's the circuit you recommended to me many years ago (around 1980?), Tom. :-) 73, Mike www.w0btu.com On Tue, Aug 14, 2012 at 5:39 PM, Tom W8JI <[email protected]> wrote: > In your system it probably comes from the antenna amplifiers. Unless you > have something local, a better amplifier might be a cure. > _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
