[TowerTalk] T Matches

[Chuck Smallhouse]

##  He also mentioned about HF yagis using the T match...and the 
200:50 ohm coax balun.   Several of them had the main lobe 
canted  off to one side by 20 degs !   The fix was to replace the T
match with a conventional hairpin setup. He did not mention the 
brand, but I suspect it was telrex... the only co I know of that used 
a T match.  Why the  lobe ended up skewed  20 degs  to one
side is beyond me.  He mentions fixing several of them.

I have very successfully used T matched VHF/UHF high gain yagis from 
venders such as Telerex, KLM, M2, K1FO and others and have never 
experienced any offset of their patterns. They all used a 1/2 W/L 
coaxial "balun" as a 50/200 ohm matching device.  In fact I've never 
even detected offset of the main lobe on Gamma matched yagis, as some 
have rumored to have experienced.

Proof of this observation, is the receiving of moon echoes of arrays 
of 4, 6 or 8 T matched yagis .  The echoes, sometimes quite weak, 
where heard when the arrays were optically pointing at the moon.

I have not read N6BT's book, I so don't know how he determined or how 
he corrected the perceived 20 degree offsets of the T matched yagis .

W7CS