[NLRS] 10Ghz weak signal source.

[Chris Elmquist]

These really are handy...  I have built one for 2, 432 and 1296 that
uses a 48 MHz oscillator and a set of dipoles for 432 and 1296 mounted
on .141 line with an N connector attached.  You choose the dipole for
the band you wish to test, attach it to the box and off you go.  For 2m,
I attach a rubber duck.  I knew there was a use for those somewhere.

I have also powered the osc can from a 5v regulator that has a 1K pot in
the ground lead so that I can tweak the supply voltage to the osc can.
This allows you to net it on freq fairly accurately and I was surprised
how stable it really was.  I have it on 1296.000 and it stays there for
hours.

I'm building another that will get on 903.000.  It uses a custom ordered
osc from Digi-Key on 33.44444 MHz.  The custom osc's are only $8 so it
wasn't an outrageous experiment.

I build these into the same little diecast boxes that DEMI puts their
preamps in and for these low bands, there is no need for an MMIC.  I just
mount the N connector in the lid of the box and put the Schottky diode
right at the back of the N connector.

Recommended test equipment.  Cheap.

Chris NØJCF

On Monday (07/11/2005 at 01:11PM -0500), Jevon (Jon) Lieberg wrote:
> 
> 
> Several people at the Saturday breakfast asked for info on my 10 Ghz 
> weak signal source that I brought. The design came from an article in a 
> CSVHFS proceedings by K2DNR. I have put the article and some pictures of 
> a source I built on my web site. 
> http://home.earthlink.net/~jlieberg00/10ghz/
> 
>  I have made some modifications to increase the output level. First I 
> use a 64 Mhz crystal instead of the 32 Mhz in the article.
> Then I added a MAR3 MMIC between the clock osc. and the comb generator. 
> I used .001 chip caps to couple the signal in and out of the MMIC and I 
> used a 150 ohm, half watt resister tied to 12vdc to power the MMIC. I 
> attached a 10 Ghz feed to it to act as a filter. When I put the source a 
> 100 feet from my 10 Ghz rig I get about an S6 signal. The source also 
> works great on 2304, 3456, and 5760 when the filter is removed. Could be 
> very useful for a rover to check out if all the bands are working.
> 
> 73
> Jon, K0FQA
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-- 
Chris Elmquist   mailto:chrise at pobox.com   http://www.pobox.com/~chrise