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 <w8ji@w8ji.com> wrote:
> In your system it probably comes from the antenna amplifiers. Unless you
> have something local, a better amplifier might be a cure.
>
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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