[amsat-bb] Re: Preamps??

Mike Ryan mryan301 at comcast.net
Sun Apr 12 14:10:57 PDT 2009

I havent tried every product out there but I'll share what I've experienced.

AES will sell the Mirage preamps (KP1440), but I cant recommend those. I recently bought one for 70cm  and was very unhappy with it. Gain was poor as was immunity from interference (i.e. my 2M uplink). 

The Ramsey PR40 amps are a fun kit to build and you cant go wrong for about the $20 price tag. Takes an hour to build but don't be surprised if you take 4 times that working out and assembling a case, housing, connectors, pigtail leads, etc. Still, its cheap and fun and a fantastic option for portable or handheld use. But this, like many other RX amps has no sense of humor when it comes to accidentally transmitting through it. It only takes one bump of the PTT to fry the transistor. Happily its a quick replacement and a $2 part. I built one and keep it as a backup. 

My everyday preamp is the ARR SP432VDG. Its a 25 watt switched model for indoor use at about $120. There is a $90 RX only version with the same vulnerability as the Ramsey and other RX only units. I know mast mounted should be a lot better but I opted for indoor use due to the lower cost and couldn't be more pleased. Lots of gain (9+ s units vs 7 on the Ramsey and Mirage) and no de-sense or interference from my uplink 3 ft away running 50 watts. The other nice thing is that its small enough that I can bring it outside with the Arrow/Elk and easily run it on a small 12 V source (pack of 8 AAA batteries).  One thing to watch out for on GASFet preamps is you should never swap connectors or antennas when they are energized. I popped my first one (wondering how since I only had 5 watts) and after a long talk with ARR, agreed that this how I may have done it. ARR customer service was also very responsive and personable (its a small company). 


-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Jerry Felts
Sent: Sunday, April 12, 2009 7:23 AM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Preamps??

I've seen Preamps mentioned several times now so Who? What? Where? I have
not seen them in the AES catalog I got the other day.  Can you build one?
Need info on them!!

Jerry - NR5A

Jerry - NR5A - South Dakota

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