> This information is taken from the instruction manual for the Autek VA1
> antenna analyst.
I believe the original poster had a bunch of short chunks, and might not
have a whole 1/4 wavelength. Same thing works, though.. measure the Z
looking into a mismatch, just you have to do more math to get the loss.
I use this method of measurement to assess
> deterioration of my transmission lines. I also measure DC insulation
> resistance and DC conductivity of the conductors. I'm reluctant to use
> a Megger. Exceeding the breakdown voltage of a line can permanently
> damage it, depending upon the kind of insulation that breaks down.
One would want to check the output voltage of the megger. If it's <1000V,
then the coax shouldn't be breaking down. The voltage rating on coax is RMS
AC volts, and fairly conservative (perhaps they take into account some
mismatch?). Solid dielectric RG-8/RG-213 is good to 20 kV DC without
breakdown (it's actually probably higher than that, but 20 kV is the highest
I've run through it on a regular basis, in air).
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|