[NLRS] New 10 GHz Player

[Donn Baker - WA2VOI/0]

HI Scott.
GOOD use of the time !  I've still got to finish up my 2nd 3W amp... its built, but haven't set the bias yet.  Maybe 
between now and next year.  :-)

Re: LMR 240... Question: Where's the RECEIVE pre-amp ?  If you don't have a pre-amp then the receive path is from the 
feed horn, thru the T/R relay, thru the 3' of LMR-240 to the XVRTR... maybe 3 dB of loss  (LMR 240 is basically RG-58 ! 
At 10GHz ??!)  That means youv'e LOST 1/2 of your receive signal before you get to the receiver and your RX noise figure 
is AT LEAST 4.5-5 dB.  Maximizing the TX is the least of your worries... if YOU can't hear'em it doesn't matter if 
they're receiving you at 20 over.

On the other hand, if you have the Pre-amp, TX amp, and T/R relay at the feed horn, LMR-240 (again, RG-58 -- shudder !) 
to the XVRTR doesn't matter.  You will need at least 16-18 dB of gain in the RX pre-amp to overcome the cable losses and 
set the noise figure of the entire system to the NF of the pre-amp.  That most likely means a 2-stage pre-amp.

While its a matter of preference, I'd recommend the back of the dish rather than a tripod leg for the mounting location 
of the rest of the stuff.  Makes the whole packge easier to move around, and faster to get working.  (At least if you're 
going to be a Rover... less of a problem if you're only to set up once or maybe twice in a day.)

73 Donn
WA2VOI/0


----- Original Message ----- 
From: "Scott" <acepilot at bloomer.net>
To: "Chippewa Valley VHF" <cvvhf at cvvhf.org>; "Don Schmelzer" <dschmelzer at sbcglobal.net>; "Doug" <k7wbc at centurytel.net>; 
<Flying_Hams at yahoogroups.com>; <gary.pelletier at gencomm.com>; "Guy" <wb5uaa at hotmail.com>; "Joe Eide" 
<jbeide at charter.net>; "Susan Littfin" <tnslittfin at yahoo.com>; <wdebjm at insightbb.com>; <whcz at juno.com>; "NLRS List" 
<nlrs at mailman.qth.net>
Sent: Saturday, December 20, 2008 10:50 PM
Subject: [NLRS] New 10 GHz Player


>
>
> Since the weather is miserable today (snowing AGAIN!), I devoted the afternoon to finishing up the 10 GHz PA module. 
> It is done and tested.  Was able to get 4W out with the full 10 mW drive from the transverter.  I set the transverter 
> drive level to obtain 2W out of the PA module.  I'm going to run at that level and see how it works out before jumping 
> up to the 3W level DEMI says it can do.  I'm a conservative after all ;)
>
> So, the guts of the system are now complete and I can turn my attention to assembling the system components together 
> and get some good RF cables to tie it all together.  I'm thinking of using a short run of UT-141 between the amp and 
> the feedhorn (the amp will be permanently mounted to the bottom side of the feedhorn arm).  Then I was thinking of a 
> run of LMR-240 from the transverter to the amp...probably around 2 or 3 feet.  I hope to be able to mount the 
> transverter on the back side of the dish or maybe to a leg of the tripod.  Comments?
>
> -- 
> Scott N0EDV
> http://corbenflyer.tripod.com/
> Flying Corben Junior Ace - Building RV-4
> Gotta Fly or Gonna Die
>
>
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