[amsat-bb] Cross boom question

Kevin Groth hislens at gmail.com
Sat Jul 25 13:47:59 PDT 2009

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?





Fort Worth, TX

More information about the AMSAT-BB mailing list