[NLRS] Homebrew gear to test at 10 GHz?

[Gerald]

On Thu, 2005-05-05 at 07:30 -0500, Chris Cox, N0UK wrote:
> 
> Peter, G3PHO, has the page that I always look to first for 3cm home brew 
> ideas.  Take a look here:-
> http://www.qsl.net/g3pho/ghz.htm
> 
> I'm not sure that there is info there specifically about measuring SWR on 
> that band, but maybe.  I have read an article on somewhere, however, I 
> think it was in print - probably in the RSGB Microwave handbook.  On the 
> microwave bands, one usually measures the return loss which can then be 
> converted to a SWR that we tend to be more familiar with.
> 
> Chris
> 
>  On Thu, 5 May 2005, Scott wrote:
> > Does anyone know of a good website(s) that has some home brew test 
> > equipment for 10 GHz use?  I would like to be able to measure SWR up 
> > there as I play with different feed systems, etc.  Thanks!
> 

In the ault days we used a slotted line with a sliding probe to see the
standing waves directly. They still are around in surplus, both
waveguide and coaxial versions. And could be made with enough tools. The
return loss bridge is most simple though requiring a couple decent
resistors, a decent load, and a differential diode detector in a box or
on a PC board with four connectors. It would be hardest to make work at
10 GHz though compared to VHF or low microwave.

A directional coupler (say 20 dB) and a diode detector presuming there's
a load built in the coupled line, or better that it has two coax ports,
so you can put a load on one and a diode on the other and then swap
those to check power in the other direction also works. You can make a
coaxial coupled line with some .141 coax with a few bends and some
filing and soldering.

There are often broad band coaxial 20 dB directional couplers on epay.


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