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Re: ARR in-shack preamps



It depends on the type of antenna. If it is omnidirectional, the thermal
noise from the earth is 6 dB higher than the cosmic noise level and changing
preamp location has a minor effect if feedline loss is 1 dB or less. If a
directional antenna is used, even 1 dB of loss in the feedline doubles the
receiver noise temperature when the antenna pattern doesn't include the
horizon.

73,

John
KD6OZH

----- Original Message -----
From: "John Geiger" <johngeig@yahoo.com>
To: <amsat-bb@amsat.org>
Sent: Thursday, February 10, 2005 06:17 UTC
Subject: [amsat-bb] ARR in-shack preamps


> I am looking to get a 70cm preamp to help with Mode J
> on receive, and have found a couple of good deals on
> the Advanced Receiver Research (ARR) 432 in shack
> preamps.  I have used these before for weak signal
> work, but not on the satellites.  Do these in shack
> preamps really help on the downlink signal, especially
> for SO50 and AO27, or would a mast mounted preamp be
> the only think that would help?
>
> 73s John NE0P
> Tired of spam?  Yahoo! Mail has the best spam protection around
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