Because the shield of the coax "looks" like a piece of pipe, and has the same effect on the antenna pattern that you're trying to eliminate by going to a non-metallic cross-boom. Jim KQ6EA
--- On Wed, 4/22/09, Jeff Yanko wb3jfs@cox.net wrote:
From: Jeff Yanko wb3jfs@cox.net Subject: [amsat-bb] Re: Cross Boom To: "Joe" nss@mwt.net, "Billy Simpkins" bsimpkins31@dishmail.net Cc: amsat-bb@amsat.org Date: Wednesday, April 22, 2009, 10:55 AM Hi all, I found this line confusing....
"But then if you go insulated then do not run the feedline along it either or you just defeated the purpose of the insulated boom."
My question is if you run the coax along an insulated crossboom, ie. fiberglass, how could that affect the coupling of the transmission line when the object it is being attached to is "insulated"?
73,
Jeff WB3JFS
----- Original Message ----- From: "Joe" nss@mwt.net To: "Billy Simpkins" bsimpkins31@dishmail.net Cc: amsat-bb@amsat.org Sent: Wednesday, April 22, 2009 7:06 AM Subject: [amsat-bb] Re: Cross Boom
It all depends on how the elements are mounted.
If at 45 to 90 degrees from the crossarm, no propblem
and use anything,
But if in the same plane then need insulated
crossboom,
But then if you go insulated then do not run the
feedline along it
either or you just defeated the purpose of the
insulated boom.
Billy Simpkins wrote:
Is a fiber glass or some other non-conductive
material necessary for a
cross boom? What or the advantages and
disadvantages versus a metal one?
Thanks, Billy KF0CK _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are
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