[amsat-bb] Re: Cross boom question

[Edward Cole]

That may be OK in country that does not 
experience snow.  I built a 437-MHz Helix using a 
wooden closet pole (painted) and it only lasted 
two seasons before the pole split from the 
wieight of the snow.  Wood makes a good stiffener 
but really does not have the strength that fiberglass has.

But one need not worry mounting CP satellite 
x-yagis on a metal crossboom.  WA5VJB analyzed 
and tested the concept proving that mounted in 
the X confiuration with cables dressed tight to 
the antenna and crossbooms negilible effects are 
seen (at least for satellite class operations).

73, Ed - KL7UW
I have used a metal crossboom for years.

At 02:24 PM 7/25/2009, Greg D. wrote:

>Wooden pole for me.  Just a regular closet pole 
>from the lumber yard.  I've never been impressed 
>by the structural qualities of plastic pipe, and 
>putting a wooden dowel up the middle of one 
>still leaves much of the structural 
>responsibility with the plastic on the 
>outside.  So, why not make it all wood?  Heck, 
>if it can support my wife's wardrobe, it should 
>be able to handle a couple of antennas :-).  How long of a span do you need?
>
>Greg  KO6TH
>
>
> > From: W0SAT at msn.com
> > To: kq6ea at pacbell.net; amsat-bb at amsat.org; hislens at gmail.com
> > Date: Sat, 25 Jul 2009 17:14:20 -0500
> > Subject: [amsat-bb] Re: Cross boom question
> >
> >
> >  Amen: I have been aluminum cross booms for several years now.
> >            Jerry w0sat
> >
> > -----Original Message-----
> > From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> > Behalf Of Jim Jerzycke
> > Sent: Saturday, July 25, 2009 4:36 PM
> > To: amsat-bb at amsat.org; Kevin Groth
> > Subject: [amsat-bb] Re: Cross boom question
> >
> > This has been gone over a zillion times.
> > Short answer; Mount them in an "X" configuration and don't worry about it.
> > http://www.g6lvb.com/fibermetalboom.htm
> >
> > --- On Sat, 7/25/09, Kevin Groth <hislens at gmail.com> wrote:
> >
> > From: Kevin Groth <hislens at gmail.com>
> > Subject: [amsat-bb]  Cross boom question
> > To: amsat-bb at amsat.org
> > Date: Saturday, July 25, 2009, 1:47 PM
> >
> > I have just finished building a set of 2m and 440mhz circular polarized
> > beams to work the birds.  (tired of standing in the heat and cold outside!)
> > I tried to save a little bit of money by 
> building a wood dowel inserted into
> > a sched 40 uv resistant pipe.  I hung the beams on either side of the cross
> > boom and it sags way too much and is ugly.  I thought about using some
> > eyebolts and some nylon cording for support to the vertical mast, but I'm
> > trying to keep everything as clean as possible for the neighbors.  I would
> > really rather not have to purchase a 
> fiberglass satellite boom commercially,
> > but if I have to, I will.
> >
> >
> >
> > I have a bunch of 1.75" aluminum pipe that would be more than able to
> > support most anything I plan to add to the antenna collection in the future
> > (1.2 and 2.4 ghz).  My question is how much 
> of a difference would it make if
> > I mounted the 2m and 440 beams in an X position to the aluminum beam?  I
> > have read some short answers that it would minimize the swr issue, but
> > haven't really found an answer that I am comfortable with.  Also, how would
> > that effect a later addition like a 1.2 or 2.4 ghz antenna.?  My current
> > antennas are a KLM 2m-14c and a 435-40cx, both circular polarized and
> > switchable RH and LH polarization.  Does anyone have any experience with a
> > metal crossboom?
> >
> >
> >
> > Thanks!
> >
> > Kevin
> >
> > N9EME
> >
> > Fort Worth, TX
> >
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> >
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