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Re: 435 small power amp?



Jim you have outlined the age old problem of CUBESAT.  We have been
asking for a solution for some time.  So far there has been only one
chip that has done this job although I feel that a discrete component
answer might be better.  Take a look at the RF Microdevices RF 2117.
It is a high efficiency 433 MHz amplifier.  We have gotten one watt out
with 30 mW of drive at 4.5 VDC supply.
    Let me warn you that this chip is NOT easy to get going. Be careful
what voltages are put on specific ports.  Heat sinking is a really a
difficult problem in spacecraft and somewhat so in balloons.  This chip
is a typical, difficult surface mount that needs careful attention.
Cliff K7RR 

Jim White wrote:
> 
> I'm looking for a small power amp that will take a 50mW UFH signal and
> provide about 2W output.  This device will go in the sounding rocket being
> built at the AFA.  Needs to be reasonably efficient in terms of DC power use.
> 
> I bought a UFH amp from Down East that uses a M677005M module.  Normally
> this nice little kit is used to provide up to 7W out for about 20mW
> in.  Bench testing shows it will provide 2W out with 4mW in, which I can
> attenuate my driver to.  However it pulls .178 A DC when idle and 1.09 A
> when driven to 2W output.  The amp must run from a battery pack, weight is
> an issue, and it must run for 20 minutes (330,000 foot flight and
> recovery).  This DEMW unit is overkill.
> 
> Anyone know of something out there, perhaps used as a driver stage
> somewhere, that would fit the need?
> 
> Thanks,
> 
> Jim
> wd0e@amsat.org
> jim@coloradosatellite.com
> 
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