The BN-86 is a rod core 1:1 balun. I take the cover off and re-solder the
connections to the SO-239 connector. I have tried a home wound balun (RG142
wound on a FT-247 core in a plastic electrical box) on my TH-7, and the SWR
curves were not right. Put the BN-86 back on and the SWR curves are now per
the book. The antenna is mounted at 70 feet.
I also tried a Radio Works balun as well. Same poor results. (I got the
antenna used and it had the Radio Works balun with it).
73
Jim W7RY
--------------------------------------------------
From: "Grant Saviers" <grants2@pacbell.net>
Sent: Wednesday, March 16, 2011 5:58 PM
To: "'towertalk'" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Hygain TH3
> I have a "new" but 20 year old TH7DX acquired from a ham that never put
> it up. Since the BN-86 factory balun is universally declared "unfit",
> exactly what is it inside?
>
> I'm prone to replace it with a ferrite bead choke balun of right ferrite
> and size, if it is 1:1.
>
> Grant KZ1W
>
> On 3/16/2011 5:07 PM, Gene Fuller wrote:
>> I certainly agree with Mike re the BN-86. The PO of the TH-6DX that I
>> rebuilt only used 100 watts so it had been no problem. However, with 1.5
>> KW
>> it's not long for this world. If you're not one to get up tight over such
>> things, the old 8 or so turns of coax maybe about 8" diameter would be
>> not
>> too bad a starting point. I realize that this is a controversial point,
>> that's why I say "a starting point'. There are certainly more elegant,
>> and
>> technically superior ways too do a balun, but the coax coil is better
>> than
>> nothing, inexpensive and quite reliably.
>>
>> Gene / W2LU
>>
>>
>> ----- Original Message -----
>> From: "Mike Baker"<k7dd@cox.net>
>> To: "'Gene Fuller'"<w2lu@rochester.rr.com>; "'Diane& Edward Swynar'"
>> <deswynar@xplornet.ca>; "'towertalk'"<towertalk@contesting.com>
>> Sent: Wednesday, March 16, 2011 5:59 PM
>> Subject: Re: [TowerTalk] Hygain TH3
>>
>>
>>> Hi Guys,
>>> I concur with the disassemble, clean, lube, reassemble list and
>>> keeping the drain holes pointed down. I have used both Penetrox and
>>> Bencher's Butter-its-not between conductors and where stainless steel
>>> hardware is use, a suitable thread lube to prevent galling of the SS
>>> threads. Nylock nuts are a blessing that helps get rid of the cut
>>> washers
>>> and makes everything stay together.
>>> When I did the last set of traps on a TH-5, I used a very sharp
>>> drill bit and drilled out the dimples carefully so the hole was cleanly
>>> cut
>>> and didn't leave a flash at the hole edge inside to cramp up the
>>> removal.
>>> When I reassembled the traps, I used a good grade of RTV (Loctite Blue
>>> Silicone Gasket Material and just plugged them with an oversize mushroom
>>> head dimple to keep out the water and grunge.
>>> When you perform your rebuild, you might want to scrap the BN-86
>>> balun (if you used one) for something a bit more efficient. If you run
>>> an
>>> amp replacement is not a question: it's a necessity. The BN-86 was never
>>> designed to handle 1500W, especially if you are running RTTY or similar
>>> full
>>> duty cycle modes.
>>> They are a good antenna. I wish I hadn't sold mine years ago.
>>>
>>> Mike Baker K7DD
>>> K7dd@cox.net
>>>
>>>
>>> -----Original Message-----
>>> From: towertalk-bounces@contesting.com
>>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Gene Fuller
>>> Sent: Wednesday, March 16, 2011 10:16 AM
>>> To: Diane& Edward Swynar; towertalk
>>> Subject: Re: [TowerTalk] Hygain TH3
>>>
>>> Hi Eddy -
>>>
>>> A few years ago I rebuilt an old heavily damaged TH-6DX. I cleaned and
>>> "greased" (Penetrox) all of the tubing "joints". Took apart all of the
>>> traps
>>> and cleaned them and "greased" all of the electrical contact areas.
>>> Replaced
>>> the hardware with ss where possible. It has worked great since and was
>>> well
>>> worth the effort. The closest thing to a problem was getting the cans
>>> off
>>> the traps because of the dimples they put in the cans after assembly. I
>>> found a piece of tubing, with o.d. just smaller than the i.d. of the
>>> can,
>>> that I could insert and tap on to force the trap form out.
>>>
>>> Gene / W2LU
>>>
>>>
>>> ----- Original Message -----
>>> From: "Diane& Edward Swynar"<deswynar@xplornet.ca>
>>> To: "towertalk"<towertalk@contesting.com>
>>> Sent: Wednesday, March 16, 2011 12:50 PM
>>> Subject: [TowerTalk] Hygain TH3
>>>
>>>
>>>> Hi Guys,
>>>>
>>>> This has nothing particularly to do with TOWERS, per se, but I'm
>>>> wondering
>>>> if anyone reading this might have an idea, or two (it'll require
>>>> CLIMBING
>>>> the tower here in any event, I'm sure!).
>>>>
>>>> Specifically, I have a Hygain TH3 - Mark III 3-element tri-band yagi at
>>>> 48'
>>>> here that has basically been idle, as I concentrated my efforts on the
>>>> low
>>>> bands for some 4 years now. Anyway, I re-discovered 10-meters with the
>>>> inordinately high sunspot count of late, and pressed the yagi into
>>>> service
>>>> there with stellar results.
>>>>
>>>> Inspired, I next tried the antenna on both 20- and 15-meters, but was
>>>> shocked to see the SWR inordinately high right across each band...
>>>>
>>>> Obviously something up there has gone awry in the preceding years---but
>>>> why
>>>> is it still A-OK on 10-meters...?
>>>>
>>>> Thanks in advance, with my vy
>>>>
>>>> ~73~ de Eddy VE3CUI - VE3XZ
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>> _______________________________________________
>>>
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