>My question... Can someone explain why there would be so much potential
>between these two radials? I've got 12 radials per vertical. The arcing
>occured when the system was aimed NE. I didn't think to check if it went
>away in any of the other directions.
The potential difference depends on where the two points on the radials
were touching and the phase difference in the feed system. The radials
are not on the ground and are not a "ground plane". They are like the
bottom half of a vertical dipole and the two "dipoles" are shorting
together.
Where they cross over can have a lot of potential difference, depending on the
phase difference at the two points. Again (to emphasize a point) this voltage
difference is from the phase differences due to the distances out from the
feedpoints and from the phase difference from the feed network required to
steer the pattern.
The ends of elevated radials can have pretty big voltages (depending on
their lengths and and the number of radials). You need to insulate them
the same way you would insulate the ends of a dipole. And crossovers
can be a problem if not spaced properly--as you just found out.
73 John W0UN
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|