[QRZ.com via rec.radio.info Admin]

Antennas, Feedlines, Towers & Rotors

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Converting TH6DXX to TH3

Posted: 22 Feb 2017 12:19 AM PST
http://forums.qrz.com/index.php?thre...to-th3.556400/

Has anyone had experience or knowledge on the possibility of converting my
old TH6DXX to a TH3 (TH6 not aesthetically acceptable for the new QTH)
looking at the instruction manual for both antenna it appears the driven
elements are quite similar, however the reflector and director are totally
different, both having only one trap in the TH6DXX.



On face value I can seen no reason why extra 15M traps could be sourced and
included into the director and reflector with similar dimensions...



Converting TH6DXX to TH3

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Measuring antenna SWR w/ a RLB & Spectrum Analyzer

Posted: 21 Feb 2017 10:51 PM PST
http://forums.qrz.com/index.php?thre...alyzer.556345/

To clarify, when you setup your Spectrum Analyzer w/ a TG to use a Return
Loss Bridge (RLB) to measuer SWR with a broadband antenna & feedline, you
connect the RLB w/o a load to the SA, then normalize the TG output first?

Then connect the feedline to the antenna and read the return loss. Correct?



Assuming the above is correct, what I dont understand are theses results of
testing a 45 feedline with a load at the other end returning this result.
With that feedline attached why am I getting...



Measuring antenna SWR w/ a RLB & Spectrum Analyzer

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End fed half wave transmission loss measurements (for real this time)

Posted: 21 Feb 2017 09:40 PM PST
http://forums.qrz.com/index.php?thre...s-time.556395/

I apologize for the last message, I had a calibration error of my VNA, now
I have it right. I thought I had 1 dB of loss, I think more realistic is
1 to 1.5 dB of loss.



I did a through measurement where I took two 64:1 transformers and placed
them back-to-back. and measured the dB loss through both transformers.
The transformers are wound for low leakage inductance and higher winding
capacitance. To simulate the inductance of an end-fed half-wave antenna, I
placed an inductor which I...



End fed half wave transmission loss measurements (for real this time)

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Anchoring a 20' tower

Posted: 21 Feb 2017 09:38 PM PST
http://forums.qrz.com/index.php?thre...-tower.556392/

I live in Kansas, notorious for winds. My father built a quite durable
tapered 20 antenna base with a mast that he had the ability to lower
through the mounting being a hinge on 2 of 3 legs and the third leg was
simply secured.



I will be installing this tower on the northern exposure of my home very
soon. His method of anchoring when he used it as a 10 meter antenna base
was a concrete slab to sit on and 3 6 driven fence posts (T posts) driven
DEEP into Kansas clay and bolted with large...



Anchoring a 20 tower

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My home-brewed QRO STL for 10-20 meters is finally done!

Posted: 21 Feb 2017 08:50 PM PST
http://forums.qrz.com/index.php?thre...y-done.491178/

My home-brewed small transmitting loop project is finally complete and
working FB. I originally decided to build one of these intriguing
antennas more than a year and a half ago but I attempted two other builds
that changed course in mid-stream and sort of got put way back on the back
burner; more details on those later.



About six months ago I took the plunge and shelled out almost $900 for a
well-made manual/hydraulic tubing roller so that I could construct a
perfectly circular loop with...



My home-brewed QRO STL for 10-20 meters is finally done!

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End fed half wave transformer transmission loss measurements

Posted: 21 Feb 2017 08:01 PM PST
http://forums.qrz.com/index.php?thre...ements.556382/

Please delete this message....

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Touching the antenna during transmission

Posted: 21 Feb 2017 07:09 PM PST
http://forums.qrz.com/index.php?thre...ission.556342/

Hi everybody, a friend of mine asked me what are the risks of touch a
dipole during transmission because he would like to install a dipole close
enough to his garden and it could be touched by his neighbors. Electric
shock, burns, what else? I remember that in a dipole the higher voltage are
located in the end of the arms so, assuming a power of 100 watt what
voltage are commonly found on they? In other words how could it be
dangerous to human health touching the antenna arms during...



Touching the antenna during transmission

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performance of Beverage antenna at 15m, 20m and 10m band

Posted: 21 Feb 2017 04:13 PM PST
http://forums.qrz.com/index.php?thre...m-band.556276/

Hi, I am suffering by S9 level noise. After searching I found two possible
solution 1) Beverage antenna ( I prefer, low cost) 2) MFJ noise
canceller. Almost all youtube videos related beverage antenna is made for
160m and 80m band. I am wonder what would be the performance of a beverage
antenna is 15, 20, 10 etc meter band?



My second question, which one would provide better performance? Beverage or
MFJ noise canceller?



73

Syed

S21SM