My SWR is rarely above 1.5:1
73
Jim W7RY
--------------------------------------------------
From: "F.R. Ashley" <gdadx2@clearwire.net>
Sent: Monday, November 21, 2011 6:57 PM
To: "Jim W7RY" <jimw7ry@gmail.com>
Subject: Re: [TowerTalk] TH7 installed but not resonant--well now sorta
>
>
> Jim you are lucky, the BN-86 is rated at only 500 watts RTTY at SWR 2.0 or
> less. Mine burned out and I replaced it with a balun from DX
> Engineering.
>
> 73 Buddy WB4M
>
> 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
>>>>>
>>>>> _______________________________________________
>>>>>
>>>>>
>>>>>
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