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Old March 4th 04, 01:46 AM
Bob Miller
 
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On Wed, 03 Mar 2004 07:54:25 -0800, Dan Richardson
wrote:

On Wed, 03 Mar 2004 13:48:12 GMT, " Stephen Cowell"
wrote:
[snip]

Yes... you can ground the antenna, in fact,
it is recommended.


There is one problem not often mentioned with connecting a j-pole to a
ground mounted conductive mast. It can increase the amount of higher
angle radiation. Mast lengths that are multiples of ½-wavelengths are
the worst for this problem and mast lengths that are odd multiples of
¼-wave produce the least.


From what I've read, there is practically no RF on the lower crook of
a "J" antenna, so why would using that crook as a mount and/or ground
attachment make much of a difference?

Bob
k5qwg



If the mast is not grounded (floating) then the situation is reversed,
½-wave would least high angle radiation and and ¼-wave the most.

NEC modeling has shown that for good low-angle radiation patterns
insulating a j-pole from a conductive mast produces more power towards
the horizon.

73,
Danny, K6MHE




 
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