The difficulty with mast mounted preamplifiers is that they have to be selected for a specific electromagnetic environment. If your environment is "hot" with a lot of ham activity, local pagers and FAA stations, the preamp may not be able to handle all of the RF, unless it is suitably narrow banded.

Some preamplifiers are broadband and some are narrow band, where you will be operating. If your environment is quiet, most any preamplifer will work well. If your RF environment is NOT quiet, you have to limit the preamp RF pass band for your activity. Otherwise too much RF gets into it and raises the noise floor, reducing the S/N

Last time I tested a ICOM 2M preamp, it performed well, less than 1 dB NF with pro test gear.

What does your RF environment look like ?

Stan, W1LE FN41sr Cape Cod

On 11/3/2011 9:18 PM, James Cutler wrote:

All,

Does anyone have any recommendations on high quality mast-mounted preamps for UHF? We're using the Icom AG-35 and not happy with the noise figure. We're going to try an adjustment described here http://www.eham.net/reviews/detail/6116.

We are looking at the amps from ARR and SSB. Any other recommendations?

http://www.ssbusa.com/gaasfet.html http://www.advancedreceiver.com/page10.html

Thanks,

--Jamie _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

Hi Jamie

In a separate email I have sent to you an article that I write for Radio Rivista 9/1993 describing with schematic diagrams and mechanical drawings my low noise GaAsFET high dinamic range and high selectivity cavity preamplifier for 435 MHz with NF=0,43 dB and gain G = 20 dB

I am using it with great success in my environment area in the bay of Naples wich is "hot" with a lot of ham activity, local pagers and FAA stations.

By the way it require a lot of mechanical work but for best performance it must be tuned for the lowest Noise Figure using only a very simple diode noise generator that was described in the article.

Unfortunately building low noise preamplifiers and tuning instruments by yourself in novadays seems to become a RF "endangered species"

Have fun.

73" de

i8CVS Domenico

----- Original Message ----- From: "James Cutler" [email protected] To: [email protected] Sent: Friday, November 04, 2011 2:18 AM Subject: [amsat-bb] Mast-mounted preamp recommendation?

All,

Does anyone have any recommendations on high quality mast-mounted preamps for UHF? We're using the Icom AG-35 and not happy with the noise figure. We're going to try an adjustment described here http://www.eham.net/reviews/detail/6116.

We are looking at the amps from ARR and SSB. Any other recommendations?

http://www.ssbusa.com/gaasfet.html http://www.advancedreceiver.com/page10.html

Thanks,

--Jamie _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb