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THE AM BULLETIN BOARD => Technical Forum => Topic started by: K6JEK on February 21, 2018, 10:56:57 PM

Title: House wire in the Sun
Post by: K6JEK on February 21, 2018, 10:56:57 PM
How well does THHN (house wire) hold up out in the weather? I used to use this stuff but haven't for many years. I'm sure you folks can tell me. I'm thinking of using it for a bifilar choke at the feedpoint of the 75M dipole when it goes back up but wonder if it will disintegrate before I do.

Title: Re: House wire in the Sun
Post by: KD6VXI on February 21, 2018, 11:26:03 PM
The clear outer insulation of the #12 or 14 will shed in a bit of time, but the actual THHN 2 or THWN 2 insulation will last for years in most climates.

I've seen it underwater for years in pipes, still good.  Unless the insulation is allowed to repeatedly flex... N that can cause ingress.

The 'romex' outer shield completely depends.  Sometimes it lasts years, other times I've seen one summer disintegrate the outer yellow sheath.

The inner wires where fine.


Title: Re: House wire in the Sun
Post by: W4WSZ on February 22, 2018, 07:41:00 AM
 I know from experience it will last 19 years...........good luck

Title: Re: House wire in the Sun
Post by: WB2EMS on February 22, 2018, 05:53:45 PM
25 so far in the NE. If you live where the sun comes out, YMMV.  ;D

Title: Re: House wire in the Sun
Post by: N3TQW on February 22, 2018, 07:28:55 PM
Presently using the stuff as a random wire for a little over 10 years without a problem. Like said earlier in the thread, the outer skin will peel off, but the actual PVC coating holds up pretty well not showing any signs of deterioration.

Title: Re: House wire in the Sun
Post by: MikeKE0ZUinkcmo on February 22, 2018, 09:28:05 PM
My antenna has been up for about 8 to ten years also with no weather related problems. Have had one breakage in that time due to high winds and the fact that it's been in the tops of some tall oaks.

Title: Re: House wire in the Sun
Post by: K6JEK on February 23, 2018, 01:10:18 AM
Thanks, guys.

Title: Re: House wire in the Sun
Post by: W2PFY on February 23, 2018, 06:58:43 PM
Thanks, guys.

Wait a minute, I didn't get my 3 cents in ;D  ;D  I used number 10 stranded, black in color and the clear part came off after a few years. It had been up for 11 years way up on pine trees maybe 75 or 80 feet and it survived all kinds of tugging from the wind but I did one thing before I put it up since it would be cut for 1.885 fed with OWL. I hooked it up to my truck bumper while the other end was tied to a tree and stretched it till it broke. I figure that was poor mans hard drawn wire. I spliced it back together and measured it again and if I remember correctly, it stretched about 4-5 feet. I did this because I didn't want one side longer than the other. It would still be up there but some loggers came in and took down the tree on the north end :( :( I replaced it with some of that wire man #13 copper clad steel stuff only because it was given to me.

The stretching did make it stiffer and in doing so, the wire somehow bound itself to the plastic covering making it somewhat hard to strip the insulation off it to spice it together?  If it were a shorter antenna, I would probably not go through all that trouble.

Title: Re: House wire in the Sun
Post by: KF9CM on February 26, 2018, 11:53:46 AM
Hi guys,
Did I miss the memo or is there something wrong with using bare wire?  ;D Other than getting shorted out by wet leaves and branches using insulated wire I don't see the significance. Perhaps I'm doing it wrong.

Tnx de Gary, KF9CM

Title: Re: House wire in the Sun
Post by: W2PFY on February 26, 2018, 12:23:03 PM
I believe the advent of insulated wire came about from the manufacture of pre made antennas. I have read somewhere that having insulated wire has an effect on the antenna length or velocity factor but I forgot just how that works. I pay no attention to those details and just put up whatever wire I have but I try to use the thickest gauge I have to limit breakage, if it is not copper clad antenna wire. Maybe some brainiac can explain the finer details of insulated over bare wire on here?

The above thoughts are for flat tops using OWL. For coax fed antennas I prefer bare wire.
I make the antenna longer than necessary and use half bolts to fold the wire back on itself to make the antenna resonant on the frequency I am interested in working. It's a pain to do that with insulated wire since height about ground and nearby objects affect its resonance point.  

This link talks about bare vs insulated (

Title: Re: House wire in the Sun
Post by: KA2DZT on February 26, 2018, 12:54:03 PM
I use 8 conductor phone wire for antennas.  Works good, stronger than you would think.  I have roles of the stuff, only thing it's good for is antennas.

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