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Re: Prime Star Dishes etc.



on 1/4/01 6:51 AM, Achim Vollhardt at avollhar@physik.unizh.ch wrote:

> I don't think any tv-sat LNC would be good for ham satellite operations,
> because the phase noise of the used DRO's is much too bad for weak
> signals with low bandwidth. They do a good job as a preamp, if stripped
> off the mixer and DRO. You can also use the FETs in it for a 10 GHz
> amplifier as they will do around 50-100 mW..

I posted what I am going to post in another message, but never saw it come
through so if it is a duplicate, I am sorry.

I am a little surprised that the DROs in these units give such bad phase
noise and have poor stability (as someone else said as well).  While I am
not overly familiar with DRO construction, I am very familiar with the
dielectric resonators themselves.  In a good dielectric puck it is very
possible to get a Q of 30,000 or more!  Additionally, the materials are very
temperature stable.  So it surprises me that the stability and phase noise
of these DSS units are so bad.  Of course we are talking about a consumer
electronics prodct so that could explain a lot!  If the resonator isn't a
good quality material all bets are off.  It's just a paradigm shift as
usually when people speak of DROs they generally are speaking of very solid
and low noise oscillators.

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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