Hi Jim, Grant,
Excellent idea. The traps did have spiders, tiny critter and
dust. Blew then all out.
Next good wx day, I will go back up and swap the balun,
after opening and cleaning it. That balun is on the HyGain
40 m rotable dipole. That would prove the balun.
One other clue, before moving the tubes away from the mast
plate, the antenna sounded on the Yaesu like there was no
antenna connected. After moving the rods away, I am hearing
the band base noise.
I did check the Yaesu which shows some better SWR than the
MFJ. For example the MFJ shows on 10m never lower than 3:1,
but the rig shows flat at 28.5 I do have a giant FM station
+ miles away...but I have never heard any noise from it.
Many thanks,
Grant
W5XB
----- Original Message -----
From: "Jim W7RY" <jimw7ry@gmail.com>
To: "W5XB" <w5xb@att.net>; <towertalk@contesting.com>
Sent: Monday, November 21, 2011 9:20 PM
Subject: Re: [TowerTalk] TH7 installed but not
resonant--well now sorta
>I have tried an aftermarket balun on my TH7. It didn't work
>very well. I had high SWR on most bands. Changed nothing
>but the balun and everything came into specification.
>
> I use a BN-86 and run 1500 watts on RTTY contesting. Never
> had a problem in 15+ years of running TH6 and TH7
> antennas. I do pop the top off and clean out the spiders
> and their friends. Just pry of the top and clean it out.
> Check the solder connections, and make sure the rod is not
> broken. Then glue the top back on.
>
> 73
> Jim W7RY
>
>
> --------------------------------------------------
> From: "Grant Saviers" <grants2@pacbell.net>
> Sent: Monday, November 21, 2011 6:10 PM
> To: "W5XB" <w5xb@att.net>; <towertalk@contesting.com>
> Subject: Re: [TowerTalk] TH7 installed but not
> resonant--well now sorta
>
>> It's been a while, but both of my TH7DXs were right on
>> the manual specs
>> for SWR all bands. All bands bad is your best lead.
>>
>> Could an element slipped position? or a bad balun? I
>> heard disparaging
>> remarks about the balun, but others say it's FB. I've
>> seen a fried
>> one. You could try a sleeve or type 31 ferrite choke
>> balun in place of
>> the HyGain.
>>
>> One more possibility - your MFJ is being overloaded by a
>> nearby
>> transmitter, it is not frequency selective - any AM or FM
>> transmitters
>> within a mile or two? Check the MFJ against a
>> transmitted signal SWR
>> measurement.
>>
>> Grant KZ1W
>>
>> On 11/21/2011 4:39 PM, W5XB wrote:
>>> Hi Mike, Bob, Jim, Jim H., and other TH7 experts,
>>>
>>> Installer didn't show, got hung up on morning job that
>>> turned out to be a "monster," and I don't mean SteppIR
>>> Monster.
>>>
>>> So...against the XYLs protests, gathered tools and went
>>> up
>>> the tower...wasn't too bad, just took it easy.
>>>
>>> Found tuning rods 1/4" from boom to mast
>>> plate...loosened
>>> all the 3/8" nuts and rotated the rods about 3/4+" away.
>>>
>>> Found 10m director attach nut 1/4" from gamma match over
>>> it.
>>> Can't reach that far...so I got a wood wedge and raised
>>> rod
>>> to 1/2" + above attach point.
>>>
>>> Blew leaves off of roof--now that hurt.
>>>
>>> Checked with MFJ analyzer.
>>>
>>> 10m SWR 2:1 (never lower) from bottom up 800 KHz.
>>>
>>> 15m SWR 2.6 (best it gets) at 20.9 Mhz.
>>>
>>> 20m SWR 2.9 (best it gets) at 13.7 Mhz.
>>>
>>> The curves: 10m decreasing SWR from 28.0 Mhz and flat at
>>> 28.8
>>>
>>> 15m increasing SWR from 21.0 Mhz
>>>
>>> 20m increasing SWR from 13.7 Mhz
>>>
>>> This one has me, elements would appear to be long,
>>> sorta,
>>> but they are exact lengths former CW owner had reporting
>>> all
>>> SWR under 2:1
>>>
>>> Coax is LMR 400 which was fine on TA33 at a kw.
>>>
>>> So it is still something wrong in matching? Bad balun?
>>> Bad
>>> driven element traps?
>>>
>>> Ideas or past experiences welcome.
>>>
>>> 73s,
>>>
>>> Grant
>>> W5XB
>>>
>>>
>>> ----- Original Message -----
>>> From: "Mike Ryan"<mryan001@tampabay.rr.com>
>>> To: "'W5XB'"<w5xb@att.net>
>>> Sent: Sunday, November 20, 2011 8:15 PM
>>> Subject: RE: [TowerTalk] TH7 installed but not resonant
>>>
>>>
>>>> Grant, The TH7 differs from the TH6 in a number of
>>>> ways...lots of people
>>>> think they are the same antenna. They are decidedly no.
>>>> The TH7 has FIVE
>>>> elements on 10 meters. It was designed to be more broad
>>>> banded on that band.
>>>> I hope that you have a TRUED assembly manual. I read
>>>> the
>>>> ideas passed to you
>>>> and the hints on what to look for. I had one up in
>>>> Virginia in the early 80s
>>>> and again ( the same antenna ) in the mid 90s. I
>>>> thought
>>>> it was a great
>>>> antenna. Good luck with it. - Mike
>>>>
>>>> -----Original Message-----
>>>> From: towertalk-bounces@contesting.com
>>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of
>>>> W5XB
>>>> Sent: Sunday, November 20, 2011 7:36 PM
>>>> To: Towertalk
>>>> Subject: Re: [TowerTalk] TH7 installed but not resonant
>>>>
>>>> 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
>>>>>
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> TowerTalk mailing list
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>>>> _______________________________________________
>>>>
>>>>
>>>>
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