[amsat-bb] Re: Problem with mast-mounted ARR preamp, help please

Mark L. Hammond marklhammond at gmail.com
Fri Dec 25 13:25:33 PST 2009

Hi Bill, 

Merry Christmas!

I'm sorry to hear about your ARR preamp problem---I have used these over the years, and unfortunately what you describe is very consistent with the GAsFET device going bad.   The 1 second of signal that you hear is from the relays working with the RF sense circuit.  It's the silence that isn't good...it should go from 1 second of weak signal to a BIG signal as the preamp circuit come in line and works....in my experience, going silent after that is a good indication that the device is shot.  

If it's less than a year old, they are likely to fix it under warranty at no charge (other than shipping to them).  I've had great service from ARR for several preamps of the years.  Even if out of warranty, I think the charge is quite reasonable, compared to the price of a new one!

Wish I had better thoughts to share, but figuring out it's really broken is often an important one...probably ought to send it in (unless you have the right device, etc. to fix it yourself).


Mark N8MH 


Subject: [amsat-bb] Problem with mast-mounted ARR preamp, help please 
From: Bill Dzurilla <billdz.geo at xxxxxxxxx> 
Date: Fri, 25 Dec 2009 12:59:16 -0800 (PST) 

Hello and Merry Christmas,

I have an ARR SP432VDG preamp, which is mast-mounted to an Elk antenna in my 
attic. This set-up has worked well until today, when I did not hear any sats 
with 70cm downlink.

I then tried to see if I could bring up the local 70cm repeaters. 
Interestingly, I could key the repeaters and hear them ID for about a second, 
then I would lose the signal completely (e.g., "This is K4" then nothing).

So it appears that the RF sensor is working and enabling me to transmit 
properly, and that when I unkey after a transmission I receive properly for one 
second, but no reception after that one second.

I'm thinking it must be a bad relay. Any thoughts or things to try before I 
send it for repair?

Merry Christmas and 73,
Bill NZ5N 

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