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Re: preamps--mast mount vs. in shack



on 11/28/00 4:54 PM, Mark L. Hammond at hammond@surrealnet.net wrote:

> I guess the 75' length has 75/100 x 1.6 = 1.2 dB loss.  So, I can get that
> far, if I did that math right.  It has something to do with signal to noise
> ratio...but not sure how to calculate it.  I understand the 1.2 dB loss,
> but I think there is more to it than just that loss...

I don't have time to look it up right now, but if memory serves me, the 1.2
dB of loss adds DIRECTLY to your noise figure.  Effectively, your noise
level has increased by 1.2 dB before you hit your preamplifiers inside the
shack.

It has a direct and detrimental affect on Noise Figure.  If you want the
best, put the preamps at the mast.  There is a BIG difference.

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

My President is George W. Bush -> The legal winner in Florida

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