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.
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"<email@example.com>
> To: "'Gene Fuller'"<firstname.lastname@example.org>; "'Diane& Edward Swynar'"
> <email@example.com>; "'towertalk'"<firstname.lastname@example.org>
> 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
>> 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
>> duty cycle modes.
>> They are a good antenna. I wish I hadn't sold mine years ago.
>> Mike Baker K7DD
>> -----Original Message-----
>> From: email@example.com
>> [mailto:firstname.lastname@example.org] 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
>> and cleaned them and "greased" all of the electrical contact areas.
>> the hardware with ss where possible. It has worked great since and was
>> 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"<email@example.com>
>> To: "towertalk"<firstname.lastname@example.org>
>> 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
>>> 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
>>> here that has basically been idle, as I concentrated my efforts on the
>>> 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
>>> 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
>>> is it still A-OK on 10-meters...?
>>> Thanks in advance, with my vy
>>> ~73~ de Eddy VE3CUI - VE3XZ
>>> TowerTalk mailing list
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