(English) KT34XA Antenna

I had the following message at cq-contest reflector, and just in case, dropping answers on my personal blog. I will use this information on the future and can show for other great guys that need same help. I have no words to say THANK YOU for everybody at that reflector...

The Message:
WPX SSB is coming, and after two weekends working at my KLM KT34XA I am still lost, because it's impossible to put SWR in goodlevels. I changed all coaxial cables, connectors. WX0B help me to put 4:1 balun working ok after being full of water. Even that balun was changed and back again just for testing KLM balun - both working on the same way. Radio is working fine. But no way to change this SWR figure: 1:1 to 1:3 all 15 m band; 4:1 all 20m band; 5:1 all 10m band. Everything seems to be ok, but the antennawas at the top of the tower all the time - almost no space to work on it at the floor. The only good news is that I am 40 and miracle of the miracles) strong enough to climb 22m high tower 10 times at each Saturday - but I am really tired!! If you have any kind of sugestion, please use my personal E-mail. Thank you and see you soon... Vitor

1) NH7A
Try Towertalk
http://lists.contesting.com/mailman/listinfo/Towertalk When you measure the VSWR, are you doing this at the output of the balun? If you have an antenna analyzer, you can actually measure the impedance at the input as well as the output. You will not want to hear this, but one time I had similar readings. I found that I had a very tiny nick in the coax and over time water had gotten into the coax. I never really saw the nick, but water somehow got into the coax. Sometimes the VSWR was ok, then at other times it went away. On some bands it was ok, but others not so. You can avoid this mystery if you have measured the VSWR at the output/input to the balun. I actually replaced my balun after getting intermittent readings, only to find out this was unnecessary. I replaced the coax from the beam to the hard line that was at the base of the tower. I later opened up the coax and noticed the lovely blue color of the braid, which indicated moisture. On another KT34XA I also had similar readings when the phasing straps between the driven elements did not make good electrical contact with the T bar and balun. I now have two KT36XA antennas, and they are vastly superior mechanically to the KT34XA.
73, Albert, also NH7A, TO5A, TM5A, 6W1RY

2) K4XS
Check you continuity on all the elements... Especially the driven lements. Other problem could be there is water in the capacitor tubes. Bill K4XS

3) NM5G
You will likely get more feedback on TowerTalk. I would take the antenna down and fix/tune it at 5 meters. The resonance difference between 5 and 22 meters is usually about 10-15kc, moving up withelevation. 73, Keith NM5G

4) N2IC
I recently went through a similar experience converting a KT-34XA to a KT-36XA. To solve the problem, I first took the antenna down ad removed each element from the boom. I erected a temporary 15 foot tower so I could easily analyze each element. I measured the resonant frequency of each element using an impedance bridge at the center of the element (you could also use an antenna analyzer, etc.), and compared with previous measurements made by K6MYC, W4EF and K1KP on their XA's.
(http://www.dellroy.com/W4EF and http://lists.contesting.com/archives/html/Towertalk/2006-02/msg00199.html). Once you make the measurements, it should be easy to see which element(s) has the problem. In my case, I found that the Rear DE was resonant way too high in the band on 10 meters. I ended up lengthening the 10 meter linear loading strap until the resonant frequency fell into the right place, which solved my XA problem. Good luck! Steve, N2IC

5) EI6BT
I suspect your problem is being caused by corrosion at one or more of the aluminium joints. All metal to metal joints should be checked with an ohm meter and this will quickly tell where the problem joints are. I have had similar problems to yours on very many occasions and I am pretty confident that the problem can be fixed by locating the poor joints and cleaning them up. This will mean taking down the antenna from the tower to do the work. I hope you get it done In time to work us in WPX!!! Best 73’s Jerry, EI6BT & EI7M for WPX.

6) LA6FJA

I made a waterproof box and a new balun of Amidon 3pcs of T2-200 cores. my KT34XA works super after 5 years in KILLER mode :) Good Luck73 LA6FJA/KI4KJP.