Hi Ed,
I am fortunate in the weather dimension, especially compared to your neck of the woods. My pole has been up, untreated, for about 10 years now, and it's starting to show signs of its age. Summer project to rebuild the array, as it's gotten quite a bit out of balance as new antennas have been added and old small ones swapped out for bigger ones.
If I had the steel pole, I'd probably use it. The wood is nice in one way, though; things clamped to it tend to stay where they are, as the teeth dig in nicely.
Greg KO6TH
Date: Sat, 25 Jul 2009 22:06:34 -0800 To: ko6th_greg@hotmail.com; w0sat@msn.com; kq6ea@pacbell.net; amsat-bb@amsat.org; hislens@gmail.com From: kl7uw@acsalaska.net Subject: Re: [amsat-bb] Re: Cross boom question
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@msn.com To: kq6ea@pacbell.net; amsat-bb@amsat.org; hislens@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@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Jim Jerzycke Sent: Saturday, July 25, 2009 4:36 PM To: amsat-bb@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@gmail.com wrote:
From: Kevin Groth hislens@gmail.com Subject: [amsat-bb] Cross boom question To: amsat-bb@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
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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