[VHFcontesting] strain relief loop for your vhf/uhf beams?

[Bill W5WVO]

I concur with Jim, there is no need for a strain relief loop, as there is no 
strain, given the method of taping or tie-wrapping to the boom that you 
describe. However, even if you did put in a strain relief loop at the 
connector, there should be no effect on pattern or anything else, assuming you 
have made a good match between the coax impedance and the antenna input with 
whatever kind of matching network you are employing. As long as the coax is in 
a plane that is at right angles to the elements, there should be no problems 
under any conditions that I can think of. Now, if you put in a big old loop 
that sticks out in a plane parallel to the plane of the elements, then you 
might develop common-mode currents on the coax, and you might distort the 
pattern. So don't do that. (As the doctor said to the patient who said, "It 
hurts when I do this...")

Bill W5WVO


Jim Forsyth wrote:
> What is the engineering reason that you need a strain relief loop even
> though the coax is supported and there is no pull on the connector?
>
> I have a dozen antennas arranged just as you describe, no problems so
> far after six years.
>
> Jim, AF6O
>
>> Of course, taping the coax to the boom supports the coax so there is
>> no pull
>> on the connector.  But the engineer in me says I should place a
>> strain relief loop at the connector.
>> Michael - N6MEF
>
>
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