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Re: Pre-amp question



Hello Al,

Your technical decision should be based on the electromagnetic
environment that you are in. If you are out in the rural county
with no other 2M operators and a radio wise quiet area the
Mirage/MFJ mast mount preamplifier would be a cost effective solution.

If you are in a dense electromagnetic environment with many 2M
legal limit operators, strong 136 Mhz FAA transmitters, and many
pagers at 152 Mhz, then you need a a low noise preamplifier
with 2M bandpass selectivity to reject all of the strong
signals NOT of any interest.

The Mirage/MFJ units DO NOT provide significant 2M bandpass
capabilities and should be considered as broad. The SSB mast
mount preamplifier is multi stage with helical filters after the first
low noise stage. (as I recall)....

If you are in a really HOT RF area.... consider the DCI, 4-cavity
bandpass filter, ahead of any preamplifier.
I use them on 6M, 2M and 222 Mhz.......

Keep in mind that all of the passive insertion losses between
the antenna and the first active device (preamplifier) add directly
to the system noise figure. If you have 10 dB of losses ahead
of your 0.1 dB low noise preamplifier,  your system noise figure
will be no better than 10.1 dB......

Stan, WA1ECF   Cape Cod, MA   FN41sr



Allen Emer wrote:

> I'm looking to install either an SSB SP2000 preamp or a Mirage KP2 (VHF)
> anyone have experience with these units? I'd hate to spend the extra bucks
> on the SSB if
> they both perform the same.
>
> Al Emer N2YAC
>
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