Thanks, Jim, Bob, and Jim H.,
Excellent suggestions all. I will summarize these and give
them all to him before he goes up the tower.
Thanks guys, these were just the kind of ideas I was looking
for.
Cheers all around,
73s,
Grant
W5XB
----- Original Message -----
From: "Jim Hargrave" <w5ifp@gvtc.com>
To: "W5XB" <w5xb@att.net>
Cc: "Towertalk" <towertalk@contesting.com>
Sent: Sunday, November 20, 2011 5:52 PM
Subject: Re: [TowerTalk] TH7 installed but not resonant
> Grant,
>
> I would be concerned about the bolt. It could be shorting
> something out.
>
> I would also have him check the straps from the balun to
> the driven element.
>
> Also make sure the coax has not pulled out of the
> connector on the balun.
>
> Its also possible the link between the two driven elements
> was bent and
> shorted together during installation. These tubes cross
> over between the
> elements.
>
> 73s de Jim
> W5IFP
>
>
>
>
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com]On Behalf Of
> W5XB
> > Sent: Sunday, November 20, 2011 3:02 PM
> > To: towertalk@contesting.com
> > Subject: [TowerTalk] TH7 installed but not resonant
> >
> >
> > 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
> >
> >
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
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