[NLRS] Salvaging DirecTV RF Amps???

[Gerald]

On Thu, 2005-04-21 at 00:57 +0000, Scott wrote:
> 
> Has anybody used the amps that are on the down converter boards of the 
> DirecTV feed horn?  I have a bunch of these feeds that quit working.  
> Maybe some of those amps might still work?  If so, what gain factor do 
> you suppose they might be?  They should work at 10 GHz with no 
> problems...Seems a waste to just toss them out if they might be useful.  
> All most of us really want is the feed itself.  See what I'm talking 
> about....
There have been articles in Central States VHF Conference proceedings or
Microwave Up Date on such conversions. Some have bandpass filters that
need to be jumpered or replaced. There is a lot of gain in the total
front end, maybe as much as 40 dB.

Though I've not tried it, I believe that chopping off the waveguide
input and dropping in an SMA connector wastes considerable NF from the
higher loss of any cable that will fit the SMA. Often the waveguide is
too small to pass 10 GHZ direct, but that can be fixed by filling it
with a dielectric. I presume that the dielectric loss will lower than
UG-141 but I could be wrong. One of those myriad of projects I've not
spent time on.

-- 
73, Jerry, K0CQ
Dr. Gerald N. Johnson, electrical engineer
All content copyright, Dr. Gerald N. Johnson