Remember EMT conduit is "made" to be bent easily..
1" x 10 feet long is easily taco'd by hand
1" usually has less than a 1/16th inch wall.
but if you are only going to have 4.5 feet of it out with a moxon on
it.. its probably going to live
Also I think they sound like small antennas if you are not planning on
rotating them.. 12' booms should be easily doable.. buy anything is
waayyy better than nothing...
pic from my rover 1 experience so far..
http://www.w9ray.org/modules/gallery/albums/rover/0488_G.jpg
Ray J
w9ray
EN44GT
160m-13cm
k4gun@comcast.net wrote:
> I'm already plotting improvements to my rover rig for June. After the
> January contest, I learned a lot of lessons. I need better antennas. That
> means I also need better masts. I've been looking at what a lot of other
> people are doing and have come up with a solution that meets my goals of
> simplicity and ruggedness. Its also quick to deploy and should be fairly
> effective. Keep in mind, this is for the "limited rover" class which means 4
> bands and low power.
>
> First, I need two telescoping masts. After a lot of searching, I can't find
> any commercially made masts that do what I need. After looking at Home
> Depot, I settled on building my own out of EMT conduit pipe. The inner
> section will be 10' long and 1" in diameter. The middle section will be 5.5'
> and 1.25" in diameter and the base will be 5' long and 1.5" in diameter.
> There will be two pins to lock the pieces in place in both the lowered and
> extended points. The upper section has 4.5' of mast space for antennas.
>
> The masts will be mounted in the bed of my truck. They will be attached to
> the steel tool box and a cargo divider in the bed. That will give 4 mounting
> u-bolts for each one and that should be pretty solid. I will also guy the
> lower 5' section to the inside of the truck bed. In this configuration, the
> lowest antenna would be 9' off the ground in the lowered position and 18'
> fully extended. The highest antenna would be at 13' at the lowest and 22'
> fully extended. All figures are a little conservative to account for spacing
> of the overlap of the tubes.
>
> The antennas I'm going with are the following: 6 meters is a Par Stressed
> Moxon, 2 meters is the M2 2M7 (7 element, 8'8" boom), 222 would be from M2 in
> the 222-7EZ (7 element 5'8" boom) and an M2 420-50-11 (11 element 5' boom).
> Everything would be oriented forward and I would use the truck to rotate the
> thing.
>
> My question becomes about stacking order. I have about 4 feet of mast space
> to work with on each mast. My thought was to put the 6 meter at the top of
> one and the 432 on the top of the other. That would allow me to stagger them
> so they didn't come too close to each other either vertically or
> horizontally. I'm very open to hearing alternatives to this.
>
> I will also have a single mast mounted to the trailer hitch with halos for
> 50, 144 and 432 for use while moving.
>
> So what says the group? Obviously, everything is a compromise of performance
> versus portability and ruggedness. I'm trying to walk a line that gets me as
> good a signal as possible while not causing me problems from overly complex
> or cumbersome systems.
>
> Thanks for any suggestions.
>
> Steve
> K4GUN
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>
>
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