On Wed, 07 Apr 1999 06:20:21 +0000 alsopb <alsopb@gloryroad.net> writes:
>
>Guys,
>
>I think the question is not whether guy wires interact but how much.
Amen!
Sometimes we hams are way too worried about a minor point.
>After all parasitic arrays are a reality (your yagi works doesn't it?
>and Lentz's law on induction hasn't been repealed by any government
>agency that I know about just yet) Induced currents in conductors
>will
>radiate.
Or be absorbed.
The crux of the matter is how much relative to the main
>radiator/array. IMHO I think the only viable tool that we as hams
>have
>to address "how much" are the antenna modeling software programs. If
>they say it's a problem, you have two choices: believe it or don't.
Modeling is a powerful tool. However a model is only as good as the
programmer and some early work did have errors.
Other models are rather poor at low heights and with real ground.
>If
>you believe it and the effect is meaningful than some fix (e.g.
>phylistran or fibreglass) maybe be in order. Which guys to
>replace/modify would be dictated by further model calculations. If
>you
>don't believe the models, then fine. Live with what you have. I've
>got
>to believe the old practice of breaking up guy wires to make them
>non-resonant (in the pre computer model days) was based upon sound
>engineering.
Which also required getting out of the chair and actually measuring
something. The formulas we use today were verified by engineers and techs
actually doing field measurements.
The difficulty is that there is just about no way to
>break
>up guy wires (expect perhaps keeping unbroken lengths down to 6' or
>less) if you want to operate all bands from 160-10 around densely
>packed
>towers and antennas like are typical for non-estate sized ham
>installations.
The 27' length that has been in the ARRL Antenna Manual for many years
works quite well for most applications. Buying 502 size insulators by the
case load directly from the manufacturer is one way to keep cost down.
A procedure used in commercial installations is to install lossy ferrite
beads on guy wires. It has been proven to eliminate IMD problems
associated with reradiation and less than perfect anchor terminations. I
have supplied the same 1" diameter beads to tower installers that I sell
to hams for sleve baluns.
73 Carl KM1H
>
>You can't fool mother nature, although mother nature can make fools
>of
>us.
>
>My two cents....
>73 de Brian/K3KO
>
>
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>
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