[amsat-bb] Re: Cross Boom

[Jim Jerzycke]

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 at cox.net> wrote:

> From: Jeff Yanko <wb3jfs at cox.net>
> Subject: [amsat-bb] Re: Cross Boom
> To: "Joe" <nss at mwt.net>, "Billy Simpkins" <bsimpkins31 at dishmail.net>
> Cc: amsat-bb at 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 at mwt.net>
> To: "Billy Simpkins"
> <bsimpkins31 at dishmail.net>
> Cc: <amsat-bb at 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
> >>_______________________________________________
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> >>
> >>
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> 
> 
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