TopBand: Beverage/Wire Lesson

[Jeffrey Maass]

I just learned a lesson: don't use 18AWG wire on antennas under tension:
THE WIRE STRETCHES!

A few days ago, I decided to string my 250' two-wire (W1WCR-style)
Beverage, and grabbed two new 500' rolls of Essex 18AWG TFFN (insulated,
stranded) wire, and laid them out across my lawn. Mounted with three 10-foot
T-poles, with 60' slopes at the ends.

The wires were tightened-up as I always do, tight enough to keep them
parallel, straight and to keep the poles erect and in place. We're not
talking guitar-string tight: just pulled tight and anchored to the pegs at
the termination/feed points.

Today, I came home and looked out the window at the closest point thereto,
and saw two sagging wires, and immediatly thought that a pole or two had
fallen down out on the lawn. When I checked, all was in place, and the
wires were still connected to each end! Some of the outer coating was
"flaking", like they do after being in the sun for 6 months or more, but
no indications of breaks.

Each of the two wires had stretched 4.5 feet in just three or four days!

CONCLUSIONS: 

   1) Use larger wire, #14 or #12;

   2) "Walk the wire" regularly: check for all sorts of problems.

73,

Jeff Maass       (jmaass@freenet.columbus.oh.us)      Amateur Radio K8ND
      USPSA/IPSC # L-1192   NROI/CRO          NW of Columbus Ohio
      25000 Members in 2000!


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