Jerry,
You are overlooking one important factor: the inertia of the
weight. Recall F=MA. First comes the force, then the acceleration, and
third the motion. If the M is considerable, enough Force is needed to
first accelerate the weight then move it that will break the wire. The
spring works on a slightly different principal. The M is that of the wire
which is insignificant. You only tension the wire with the spring so that
the catenary is the same as it would be without the spring. Then a sudden
pull will imedately stretch the spring, the tension is increased only a
very little, whereas a sudden tension will not move the weight fast enough,
the tension increases, and it enough, the wire breaks. My antenna with the
#22 wire broke with a weight on it. I added the spring first and it didn't
break any more, but after that I changed it to #14 wire. I say that to use
both is the best approach.
Chas, W1CG
At 03:33 PM 9/10/2004, [EMAIL PROTECTED] wrote:
Weights and springs both work to tension wire antennas...Weights are said
to have the disadvantage of "rebound", but I have never experienced that
here in the northeast...Springs increase the tension on the wire
tremendously as the tree sways and the further the tree sways, the
greater the tension...This can stretch the wire and exceed the breaking
point of some element of the antenna assembly...The tension will always
be the same with a weight, no matter how far the tree sways...For the
last 4 years I have had a 30 meter dipole up using a 2 gallon plastic
orange juice container filled with water and anti-freeze...Works for
me...
Jerry, wa2dkg
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