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Old February 25th 13, 06:50 AM posted to rec.radio.amateur.antenna
Sal[_4_] Sal[_4_] is offline
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First recorded activity by RadioBanter: Feb 2013
Posts: 68
Default Homebrew 222 Mhz Beam Antenna Project


"tom" wrote in message
. ..
On 2/24/2013 9:13 PM, tom wrote:
I've done some searching for corrections for through the boom
uninsulated and found that the opinion is that it's not a good idea. And
it makes sense if you read why - the current is really high at the
center of the element and any variation in contact resistance to the
boom or material will change the result.

What you would like is the result to be based on only the insulated
element conductance and the shielding of the boom, which is easier to
calculate and less variable.

tom
K0TAR


Here's a reference that mentions reasons for not using uninsulated through
the boom connectio9ns. And has some nice graphs on insulated through the
boom.

http://g7rau.demon.co.uk/sm5bsz/antennas/sa/others.htm

tom
K0TAR



OK, I'm convinced. What I need is some lightweight non-metallic material
for the
boom and I can build with the numbers I have for element lengths. I'll hit
the stores
in the morning.

I'll try a T-match, too.

"Sal"