[TowerTalk] Long Wire Sag

[Jim Brown]

I have a strong dislike for copperweld -- I find it miserable to work 
with, and neighbor W6GJB had a #12 copperweld 80M dipole break a few 
days after paying climbers almost $1K to rig it in his tall redwoods.

My wire antennas are at 140 ft between redwoods, and fed with RG11, 
rigged with pulleys, tied down at on end and a 90# jug of dry sand on 
the other.  I used to use THHN, #10 on permanent antennas, #14 for 
portable ones, but the #10 THHN stretches over time if under tension, 
and must be circumcised every few years.

If insulation is not needed, a far better approach is to buy a spool of 
#8 bare copper from the big box store and stretch it to approximate #9 
hard drawn copper. WA6NMF introduced me to this idea around 2004, and 
neighbor W6GJB and I have done it several times since. We tie one end of 
about 200 ft of wire to an immovable object, like a tree or telephone 
pole, the other end to the trailer hitch of his pickup, and Glen drives 
very slowly until it breaks, while I observe at a distance.  The stretch 
is typically 15-20%.

73, Jim K9YC

On 3/10/2019 8:25 AM, Gedas wrote:
> I am planning to put up a long inverted v antenna with it's feedpoint 
> at 85' using 600' total wire (300' on each leg). The ends will be near 
> the ground, only 20-25 feet high.
>
> My question is given that each leg of this antenna will be 300' long 
> am I better off going with a lighter weight #14 THHN insulated 
> stranded wire or some heavier #12 THHN stranded? I am not going to 
> purchase a different wire that would be better suited like copper-weld 
> etc since I have plenty of these other two and want to try something 
> today.
>
> I realize there is going to be a _lot_ of sag in either case but I am 
> not sure of the breaking strengths of either #12 or #14 and in the end 
> which will help keep the wire up higher with less sag. Any ideas?
>
> Gedas, W8BYA
>
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