[amsat-bb] Re: Pre-amp for IC-910h?

Jim Sanford wb4gcs at amsat.org
Tue Mar 27 18:09:26 PST 2007

In my permanent microwave station setup, I wish to run a sequencer.  
Doing that with rig preamp power up the coax is do-able with some rigs, 
but problematic.  I prefer the flexibility of dedicated powe or control 
for everything mounted at altitude.  Given distributed transverters, 
power amps, downconverters, and preamps, it seems to me the safest and 
most flexible way to do it. 

In particular, ICOM is very blunt in their manual:  Don't put anything 
(like an external power amp) between the rig and preamp if you're using 
the rig to provide preamp power.  Not hard to figure out ways to make it 
acceptable, but also not hard to figure out how it can go sour, 
resulting in a cooked preamp.  (been there, done that.)

In my ultimate satellite station, I'll have at least some power amps, 
and possibly upconverters at altitude.  I want more control than the 
rig-powered preamp offers.

Don't get me wrong -- I am NOT bashing Icom or Yaesu for their 
implementations of  power up the coax.  For a simple (not minimal) 
station, it's more than adequate.  It's just not adequate for my 
(hopefully) "bleeding edge" final station configuration.  If I had to 
parachute into a disaster area with some batteries, my 910 , coax, and 
preamps, I'd use power up the coax in a microsecond -- with confidence.

Hope the clarifies the question!

Thanks, 73, and good luck!
wb4gcs at amsat.org

Jeff Griffin wrote:

>  I'm curious Jim, why wouldn't you supply power to the pre-amp through the 
>coax in a permanent setup?
>73 Jeff kb2m
>----- Original Message ----- 
>From: "Jim Sanford" <wb4gcs at amsat.org>
>  While I'd never use power up the coax for a final
> installation, it sure is nice for Field Day. 
>Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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