[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: K3TZ Patch Design Web Site Update



I was interested in Tim's design, as it looks like one easily reproduced by the average ham in his garage (as pointed out by Fred).  The issue of linearity v. circularity aside, I wanted to see how easy it was to build and how it performed compared to a helix.  I built Tim's patch using some thin gauge aluminum stock found at the local Lowes for about $5 a sheet.  You can see a picture of my quickly-cobbled patch feed at:
http://home.swbell.net/k5oe/patch_09.jpg

I then set up a "controlled" test in my driveway using a surplus 18" DSS dish, a 3731 from K5GNA, a comparison helix feed in a cup (I had laying around from an earlier project), my FT-100's S-meter as a signal strength meter, and AO-40's MB as a signal source.  You can see a picture of this "very professional" setup here in my driveway Sunday afternoon (no laughs, please):
http://home.swbell.net/k5oe/test_18.jpg

The patch needs a scaler ring (or cup, I measure about 1" or so to cut off the edge-of-dish) and the helix is a little short for this dish (4-1/2 turns and should have been at least 5-1/4 turns), but the test was just an "order of magnitude" comaprison.  The patch outperformed the helix by a full S-unit (around 3 dB on that meter).  I admit this was a crude test, with neither feed being tuned with any kind of instrument, but it was a good test of what the average ham could build in his garage with hand tools and no access to measurment instruments for S-band.

I look forward to Tim perfecting this design (revision 2 coming soon to a theater near you) and figuring out how to get circularity as well as brute linear performance.
73,
Jerry, K5OE


Tim ZIbrat writes:

> Hello all,
> 
> I have recently updated my web site for my patch antenna design.  Hopefully
> I have made it a little easier to find information on it.  It is still under
> construction and I have a lot to add, but I recently finished up some
> polarization testing and posted the results there.  I know there were quite
> a few people here that were waiting for these results.
> 
> I have received several notes pertaining to the polarity of the patch I was
> working on and I couldn't confirm if the patch was circular or linear.  The
> simulations I performed on it looked excellent.  However, after testing the
> design under controlled conditions, I found that it was in fact linear.  The
> good news is that the simulations predicted that it had just under 9dB of
> gain and this was proved in the recent testing.
> 
> The new web site with the results of this testing and how I did it can be
> found here:
> http://www.qsl.net/k3tz/index.html
> 
> It looks like it is back to the drawing board.  This has been a very
> exciting and fun project so far.  I would like to thank everybody that has
> dropped me a note of encouragement and/or help, and to all those that have
> built and used this patch, all with great success I might add.
> 
> I will keep you informed of revision 2 of the K3TZ patch.
> 
> 73,
> Tim
> 
> 
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org


----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home