Looking for help on my "new to me" TH7DX.
Was not used couple of years, cleaned it up, read and used the manual, put it
together, and put it on top of an asphalt shingle roof at 25 ft.
Checked with MFJ analyzer, and found it resonant low, about 13.7 Mhz as
expected. The other bands were low too, but 10 m was about 2:1. It "heard"
almost as well as the TA33. Figured, all ok.
Due to back injury (lawn mower accident!) can't climb right now, so I had an
installer take the TA33 down and put the TH7 up on 65' self supporting tower
with no surrounding obstacles.
Now the antenna is not resonant anywhere. Best SWR is 9:1 at 14 Mhz, resistance
is 10 ohms, x=57. Coax checks with .9 db loss. The "hearing" is now about nil,
like a wire hooked to a piece of coax.
Have looked at the antenna with binoculars. The attach points for both driven
elements look as they should, but I can't see the gamma match from the ground.
The installer is not familiar with the TH7, but has put up dozens of SteppIrs,
and monobanders. He did mention something about "adding a bolt near the Gama
match tubes" ... not sure what he did. Boom support is Philly Strand.
Will of course show installer, the assembly manual and ask about the added bolt.
Installer is coming back Monday afternoon to check out.
Any clues about what to check, greatly appreciated!
Many thanks and 73s,
Grant
W5XB
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