Re: [amsat-bb] M2 Fiberglass Boom preparation

["Edward R. Cole" <al7eb@xxxxxxxxxxxxx>]

>From: "Gary \"Joe\" Mayfield" <gary_mayfield@hotmail.com>
>At the risk of replaying a recent discussion on the list.  I now use a steel
>crossboom.  I was convinced of the feasibility by the careful experimental
>work of Kent Britain, wa5vjb,  (antenna guru).  You can read the results of
>his work in the proceedings of the 11th annual AMSAT-NA meeting.  His paper
>is titled "Using Metal Booms to Support AMSAT Antennas".  The paper has been
>reproduced on the web (I can't find the link at the moment).
>
>This is one of those things that everyone says can't work, because, well
>they know it can't.  The people who have actually done the experiments say,
>gee I guess we all assumed wrong.
>
>Yes, you do have to take a little care in how you do it!

When I put up my antennas this June for AO-40, I decided to use a metallic
cross-boom rather than go the expense of fiberglass.  Initially, I drapped
the coax off the tail-end of the 436CP42 boom but the weight of the coax
warped the antenna clamp, so I doubled the coax back along the boom to the
cross-boom, neatly tywrapping it along both booms.  I have no quantitative
data, but it is working fine on mode-U with 10-50w.  Nuf said.

Some of AO-40 operation is "rocket science" some is common sense ;-)
Ed
PS: I do use a 3-inch aluminum crossboom with four 1-1/2-inch fiberglass
risers [H-Frame] for my 2m-eme array of four M2 2m-xpol-20's.  For eme it
is necessary to get a clean pattern, especially for Rx.

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