If there are sulfur compounds in the insulation, you'll get corrosion over
time. Add water, temp cycles and sunlight, what a chemist's delight. ---
Ciao baby, catch you on the flip side.
GEO
http://www.w3ab.org
Time flies like an arrow, fruit flies like a banana.
From: "towertalk-request@contesting.com"
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To: towertalk@contesting.com
Sent: Wednesday, December 28, 2016 1:18 PM
Subject: TowerTalk Digest, Vol 168, Issue 78
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Today's Topics:
1. Re: UV and WX deterioration of THHN insulation, and effects
(Rob Atkinson)
2. Re: Copper Wire For Antennas (Wes Stewart)
3. Re: UV and WX deterioration of THHN insulation, and effects
(Wes Stewart)
4. Re: Ground plane wire (Guy Olinger)
5. Homemade Hard Drawn (Paul F. Merrill)
6. Re: UV and WX deterioration of THHN insulation, and effects
(Guy Olinger)
----------------------------------------------------------------------
Message: 1
Date: Wed, 28 Dec 2016 14:43:52 -0600
From: Rob Atkinson <ranchorobbo@gmail.com>
To: towertalk <towertalk@contesting.com>, Guy Olinger K2AV
<k2av.guy@gmail.com>, Guy Olinger K2AV <guyk2av@gmail.com>
Subject: Re: [TowerTalk] UV and WX deterioration of THHN insulation,
and effects
Message-ID:
<CALWD7Z7T+TW-HJUdRt3ZV1LgwOGzynPPJfgSS038MhjOD6VOmQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
I wish to apologize for the caustic tone of my post this morning in
which I questioned Guy's statements regarding degradation of RF
current conductivity in THHN insulated copper wire over time in UV
exposure. While I stand by my belief that his findings are flawed,
there was no excuse or reason for me to express myself in such a
contentious and abrasive fashion. I believe Guy's intentions are
good--perhaps is wire samples are made to different standards, or
there are or were manufacturing variations between what I have worked
with and his. At any rate I question what he has found, but I believe
my questioning could have been much more professional and I am sorry
it was not.
73
Rob
K5UJ
------------------------------
Message: 2
Date: Wed, 28 Dec 2016 13:50:58 -0700
From: Wes Stewart <wes_n7ws@triconet.org>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Copper Wire For Antennas
Message-ID: <7483cae2-3208-6d81-c7b1-5ce8ad6a9aac@triconet.org>
Content-Type: text/plain; charset=utf-8; format=flowed
I never buy wire at the big box. Here in Tucson we have an electrical products
store that caters to the trade, but likes business from DIY too. They are
about
half the price of big box and they are locally owned. Find one in your
neighborhood.
If you actually want drawn wire to break (why I don't understand) bend it a few
times or put a kink in it at one end.
On 12/28/2016 1:09 PM, Hank Garretson wrote:
> On Wed, Dec 28, 2016 at 11:09 AM, Jim Brown <jim@audiosystemsgroup.com>
> wrote:
>
>> There's another very practical issue with the use of ordinary copper wire
>> for antennas hung between supports -- copper stretches! I found that my
>> high dipoles strung between trees at 130 ft with the tension needed to keep
>> then sort of horizontal with 160 ft or so of RG11 trying to drag them to
>> the ground stretched enough that I must lower them and circumcise them
>> every few years.
>>
>> A far better solution is to buy #8 solid bare copper from your local big
>> box store and hard draw it to #9. In effect, you're pre-stretching it. :)
>> Pretty simple. lay out 200-250 ft of it, tie one end to an immovable object
>> (tree, utility pole) the other end to a trailer hitch on your towing
>> vehicle, and very slowly pull while an assistant observes. When it breaks,
>> coil it up and repeat. With assistants, I've done this for four 1,000 ft
>> spools, each of which yields about 1,200 ft of #9. :)
>>
> Do you have a trick to make sure it breaks at one end or the other instead
> of the middle?
>
> 73,
>
> Hank, W6SX
------------------------------
Message: 3
Date: Wed, 28 Dec 2016 13:56:26 -0700
From: Wes Stewart <wes_n7ws@triconet.org>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] UV and WX deterioration of THHN insulation,
and effects
Message-ID: <de263eb8-3e3a-6488-5335-339990eeb92b@triconet.org>
Content-Type: text/plain; charset=utf-8; format=flowed
We've all done it.
On 12/28/2016 1:43 PM, Rob Atkinson wrote:
> I wish to apologize for the caustic tone of my post this morning in
> which I questioned Guy's statements regarding degradation of RF
> current conductivity in THHN insulated copper wire over time in UV
> exposure. While I stand by my belief that his findings are flawed,
> there was no excuse or reason for me to express myself in such a
> contentious and abrasive fashion. I believe Guy's intentions are
> good--perhaps is wire samples are made to different standards, or
> there are or were manufacturing variations between what I have worked
> with and his. At any rate I question what he has found, but I believe
> my questioning could have been much more professional and I am sorry
> it was not.
>
> 73
>
> Rob
> K5UJ
------------------------------
Message: 4
Date: Wed, 28 Dec 2016 15:59:45 -0500
From: Guy Olinger <k2av@contesting.com>
To: W0MU Mike Fatchett <w0mu@w0mu.com>
Cc: Towertalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] Ground plane wire
Message-ID:
<CANckpc1-47ALVggksnkWqJFWEF=5w=j6X8HT4u3DPb1EDTtWcQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
For buried radials, particularly, I would not bother to scrape the enamel
off #16 enameled other than to connect and solder.
Enamel is not the same thing as whatever PVC soup du Jour that is being
used on THHN for insulation because that's what they happen to have in the
barrel in China today.
The question about insulation on radials, has to do with a murky question
about whether bare radials are better than insulated in a dense and uniform
buried radial system. That is not related to THHN buried with insulation,
other than the choice in this bare vs. insulated question.
Bare wire buried radial current measurements, from all the way back in 1937
in the Brown, Lewis and Epstein study, have some interesting aspects, which
add to the murkiness in the question. To my mind it isn't settled either
way and not likely to be settled. Just bury it.
73, Guy K2AV
On Wed, Dec 28, 2016 at 12:55 PM, W0MU Mike Fatchett <w0mu@w0mu.com> wrote:
> Naw just use a knife and scrape off that enamel.
>
>
>
> On 12/28/2016 10:46 AM, lstoskopf@cox.net wrote:
>
>> Gee guys, I've a 60 pound roll of #16 ga enameled wire sitting in the
>> basement. Got it from a motor rewinding business that went broke. Now I'm
>> afraid to bury it because it is safer in the basement. N0UU
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
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>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
> _______________________________________________
>
>
>
> _______________________________________________
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>
------------------------------
Message: 5
Date: Wed, 28 Dec 2016 21:11:32 +0000
From: "Paul F. Merrill" <marinesvcs@gmail.com>
To: towertalk@contesting.com
Subject: [TowerTalk] Homemade Hard Drawn
Message-ID:
<CAM42371E5Tz8L+V6+v1WVB-tyF_tnB1iPAefOyjU=yNxbuCkow@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
> Do you have a trick to make sure it breaks at one end or the other instead
> of the middle?
Put an overhand knot close to one end or the other. That should reduce the
strength by about 50%.
------------------------------
Message: 6
Date: Wed, 28 Dec 2016 16:17:26 -0500
From: Guy Olinger <k2av@contesting.com>
To: "john@kk9a.com" <john@kk9a.com>
Cc: Towertalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] UV and WX deterioration of THHN insulation,
and effects
Message-ID:
<CANckpc29x0u6DrtWvQyT+oZUi9VRNtdrVtjQO_uBa+kf_Dje6w@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Bare wire up outdoors over ten years, just what I would term a patina on
the outside.
This is in contrast to what happens to bare copper used in a woven coax
shield which has become waterlogged, where cable loss increases
significantly, and sometimes stripping reveals green crumbly stuff in and
around the shield for the entire length of the coax.
The difference in the long term between the two, perhaps is that the
elevated copper wire gets wet, the water largely drips off, and then it
dries off.
The copper in the coax shield, once penetrated with water, has the water
held to the copper 24/7/365. This may be the problem with the insulation on
the THHN in question, that it becomes water porous and holds water, and
whatever breakdown compounds against the copper indefinitely
73, Guy K2AV
On Wed, Dec 28, 2016 at 8:27 AM, john@kk9a.com <john@kk9a.com> wrote:
> Bare copper oxidizes. Visibly it appears worse than wire covered with PVC.
> Have you compared these measured THHN surface losses with bare wire that
> has been outdoors the same length of time?
>
> John KK9A
>
>
> Subject: Re: [TowerTalk] UV and WX deterioration of THHN
> insulation, and
> effects
> From: Guy Olinger <k2av@contesting.com>
> Reply-to: k2av.guy@gmail.com
> Date: Wed, 28 Dec 2016 01:28:41 -0500
>
> Current betting money in my neck of the woods is on some actual
> deterioration of the surface of the copper caused by compounds in the
> degrading insulation. Skin effect forces some degree of current into
> the degraded copper which has a higher resistance than the non
> deteriorated good stuff in the middle of the wire.
>
> What is not in question is the higher effective resistance of the
> conductor + whatever the insulation has turned into at RF after
> degradation. That has simply been measured.
>
> 73, Guy K2AV
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
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