[amsat-bb] (no subject)

Zach Metzinger zmetzing at pobox.com
Thu Sep 1 16:17:17 UTC 2016

On 09/01/16 11:01, jeffory broughton wrote:
> I have had several FT 847 radios.Great low cost choice and works well with
> satpc32.However ,for just a few dollars
> More get a used IC910. Much better rx sens with a lower noise figure.Also
> DNR circuitry.Make listening for long periods a pleasure,not so exhausting.
> Also if you compare the specs of the IC910 and IC 9100 uhf and vhf
> SECTIONS, you will see they are IDENTICAL!

I wouldn't focus on noise figure at the receiver, unless you happen to
have 1' of cable between the rig and your antenna. Instead, I'd put a
bias-T-powered LNA at the antenna to preserve your SNR (Friis formula).

Having recently built a U310-based LNA, I can say that a single night's
work of soldering and testing pays off well. Total parts cost was in the
$5 range.

I plan to build a new LNA based on a pHEMT just for fun. Only a couple
of bucks from Digikey. Why settle for 1.0dB when you can potentially get
0.25dB! :-)

--- Zach

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