I have a 2 meter repeater made from a GE Mastr Pro located at a hi level RF
site with TV, FM broadcast, & land mobile VERY near by and/or on the same
tower. I use a 6 cavity pass/reject duplexer. I notice definate improvement
WITH an (ARR) GaAsFET pre-amp AND a extra pass-cavity on the input. (I hear
Angle Linear is also good - possibly better, someday I will try one)
But obviously, that is MY LOCATION and others may be different. I know that I
have walked into other repeater locations where repeater owners could not
figure out how to get rid of their desence or intermod problems.
Replacing all their rg-58/rg-8/rg-213/whatever jumpers with rg-214 AND using
the CORRECT type connector at each end (rather than a bunch of a of adapters)
can make a big difference in cleaning up the crap the receiver is seeing.
Bob Dengler <[EMAIL PROTECTED]> wrote:
> Well, considering the natural noise floor at 70 cm is near kTB (-132 dBm in
> a 16 kHz bandwidth, or 0.056 �V) & 0.5 �V is 20 dB above that, I consider
> it a bit deaf even considering the amount of signal above the noise floor
> required to achieve 20 dB quieting. Fortunately, a GaAsFET preamp with
> pass cavity ahead of it helps remedy that little problem.
>
> 2 meters is a little different since most G.E./Motorola radios have a
> little better sensitivity, & the noise floor of 2 meters is much higher. I
> once measured the 2 meter noise floor here to be ~3000 K, or -122 dBm in a
> 16 kHz bandwidth. That's wny I almost never recommend a preamp ahead of a
> G.E. VHF receiver, but always for a UHF.
>
> Bob NO6B
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> Yahoo! Groups Links
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