[TowerTalk] Long Wire Sag

[Bob Shohet, KQ2M]

Hi Gedas,

I use #10 for 160,  #12 for 80 and #14 for 40.

The #10 NEVER breaks – not even in frequent ice storms  – only the wire connectors that I use with them.  #12 for 80 almost never breaks and #14 breaks after enough wear and tear in 1 – 3 years especially in a high wind environment where flexing of the outer coating is commonplace and where significant tension is involved. 

I believe that #12 THHN SOLID (not stranded) is the best compromise of weight, strength and cost.  #14 will break given enough time and the few bucks that you save with it over #14 is not worth it.  In my experience the difference in weight should not be significant unless you are supporting a lot of ice.  I know that the Wireman sells a #13 pvc coated poly – and I used to use that but found that its life expectancy was significantly less than the #12 THHN and #14 THHN that I could buy for a fraction of the cost at Home Depot or Lowe’s in a 500’ spool.

I strongly recommend SOLID and not stranded because in my experience the stranded THHN breaks more frequently than the solid. 

The #14, weighing less than #12, will have less sag, but is not as strong, will flap around more in the wind it is not as strong and is far more likely to break under tension, especially when supporting ice or wet snow.

73

Bob KQ2M


From: Gedas 
Sent: Sunday, March 10, 2019 11:25 AM
Cc: towertalk at contesting.com 
Subject: [TowerTalk] Long Wire Sag

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

Gallery at http://w8bya.com
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This is why some people appear bright until you hear them speak.

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