[amsat-bb] Re: Amplifier Suggestions?

Tom Clark k3io at verizon.net
Wed Sep 21 22:45:22 PDT 2011

James, KF6RFX asked:

> We are looking for a UHF amplifier (430-440MHz) for a transceiver to go from
> 10 mW to ~ 75W.  Most of the amps were are funding require a much stronger
> input power than we can do. Note, it's a transceiver, so we want to be able
> to receive through the system as well.  This is for half duplex satellite
> communication using a USRP radio.
> Do you have any suggested amps?

You might want to check with some of the "custom" amateur shops like 
Pure RF (http://www.purepowerrf.com/), Downeast Microwave (DEMI, 
http://www.downeastmicrowave.com/) or DB6NT 
(http://www.kuhne-electronic.de/en/home.html). In particular, DB6NT has 
50mw in, ~50w out amplifier 
that is close to what you ask for.

You didn't mention price constraints. Any of the "conventional" amateur 
"bricks" are will probably set you back $500-$750. There are some 
commercial alternatives you might look at. In particular check out 
MiniCircuits; at the $2000 level, the LZY1+  
(http://www.minicircuits.com/pdfs/LZY-1+.pdf)  has 39+ db gain and will 
produce 50 w of RF on either 2M or 70cm. Their older ZHL-50W $1400 brick 
(http://www.minicircuits.com/pdfs/ZHL-50W-52.pdf) is also a good unit. 
On the MiniCircuits units, I'd strongly advise that you get it with 
their BIG heatsink/fan.

You say you need fast half-duplex. I presume that the downlink will be 
on a different band (like 2M). If not, the selection of T/R transfer 
relays will not be easy, especially if you want to avoid zapping your LNA.

Good luck & 73,
Tom Clark, K3IO

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