[TowerTalk] Various aerial wires vs THHN Re: [Antennas] .#14 COPPER ANTENNA WIRE

[DavisRFinc@aol.com]

Hi all, I noticed the 3 comments on THHN and must add a few points.  I'm a 
ham of 39 years (from age 13, so as not to date myself too badly.. HI) and I  
have a company that does cable design as well as std. cable distribution.

THHN is soft drawn copper.  It can be prone to stretching if counter reliefs 
are not prperly  installed to avoid over strain.  The clear film that one 
commentor mentioned that pealed off is a mylar moisture protector, although 
the PVC insulation under the mylar is fairly moisture proof.  The outer mylar 
always comes off fairly soon in UV.

The PVC on THHN is not a good UV resistant PVC becuase THHN is not rated for 
outdoor applications.   However, I've seen it up there for 5 years or so 
without concerning degradation.
   As far as velocity factor goes at HF in solid #12 or #14, my opnion is 
that any oxidation will be inconsequential to VP or  performance. 

   THHN can be used, and it IS cheap.  Best place to get it is Home Depot, or 
similar.

However, I have learned from customer experiences that it gets very 
frustrating, and expensive, to have an aerial up for a few to 5 years or so, 
or less, and have to deal with a problem after battling with trees, tower, 
counter weights etc.   Most of them switch to what I do on my stuff and that 
is to put the best up and have it up there for 20-25 years, Yes, you will pay 
17 cents a foot for a black Polyethylene jacketed # 14 (only available from 
us and our dealers) but PE has no plasticides so it is totally UV resistant 
and the FLEX-WEAVE Tm (our design and Tm) is a 168 strand (#14) or 259 strand 
#18, which likes to flex and stay in tact in high winds and New England 
hurricanes (another negative of solid soft drawn or even hard drawn copper)  
We also have various coppers, copper welds, bare and UV jacketed from #13 up 
to Stealth # 26.   
Hope this is of some help and glad to answer any more questions.
Cheers,.  Steve Davis, K1PEK,  DAVIS RF Co.  
------------------------------------------------------------------------------
---------------------
DAVIS RF Co., commercial wire and cable, custom cable design.  Discounts to 
hams.  Heliax, LMR, RFS, Belden, BURY-FLEX Tm.  Various aerial wiring; wire 
aerial parts; transmission lines, insulators, baluns, RF connectors and 
Dacron rope.  www.davisRF.com .  1-800-328-4773, (For all RF hardline related 
items, please ask for Steve Davis)   Thank you!
 
In a message dated 01/20/2000 12:03:52 AM Eastern Standard Time, 
KF4HAZ@qsl.net writes:
<< Why go to the trouble to split out Romex,
  when it is cheaper to buy TW or THHN which comes in 500' spools.
 A good electrical supply will have THHN (single conductor used in conduit)
  and in many cases they also have spools of bare copper (cheaper still).
 
 Personally I prefer THHN over bare copper,
  while it is true the bare has a higher velocity factor initially,
  it will quickly begin to oxidize and the velocity factor drops.
 Where with insulated, if you seal the ends, it will remain constant.
 
 73 from KF4HAZ 
  >>

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