Best Plastics, Composites, Rubber for structural antenna parts

90322 Views 212 Replies 43 Participants Last post by 300ohm, Oct 10, 2013

stampeder

Discussion Starter · Nov 26, 2008 (Edited)

Just a warning note about using ABS for structural parts that I've mentioned many times before - hopefully what you're planning to use is the thick walled stuff that has little or no flex. If you go to Rona or Lowe's or Home Depot and shake a 10 foot ABS pipe like a sword it flexes a lot.

It seems to be rigid, but its not. If you shake a length of PVC like that it will seem like a wet noodle, so avoid using PVC for structural use either, except when recommended in build plans.

From experience I'm clarifying that ABS should never be used as a pole or mast, and it should be carefully considered if you're thinking of using it as a horizontal boom of any length more than a meter or a few feet.

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coloradotrout

· #206 · Oct 3, 2013

carbon arrows as reflectors

Anyone know if those carbon hunting arrows can be used as uhf reflectors where aluminum foils is wrapped around them?

They are ridgid, straight (as an arrow ;-) ) and strong.

I used what I think was mostly a fiberglass one, but needed another. The $3 one at WalMart says "carbon composite" or such.

Will the "carbon composite" itself act as a reflector? I'm hoping "no" so that my aluminum foil tape wrap approach will work.

What do others use for this?

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coloradotrout

· #207 · Oct 3, 2013

material for reflectors

What's a good material for the split reflectors -- those that are 12" or so on the left side and 12" or so on the right, with a few inches inbetween?

I am using an arrow shaft (hunting arrow). It's a carbon composite material, but nicely 27" long such that 12.25" on each side with a 2.5" gap is perfect. I wrap around it some aluminum foil tape.

What's are others using?

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coloradotrout

· #210 · Oct 7, 2013

PVC frame

I've seen the original frame, but am wondering for a GH2n2 if I should put the main element directly on the frame and then use pvc t-coupler standoffs to mount the 2 uhf relectors, narods, and 2 vhf reflectors?

The frame would be something like this:

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with the center verticals spaced to support the interior antenna elements and the outside verticals to support the antenna "tips" and also to support the reflector standoffs.

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coloradotrout

· #212 · Oct 9, 2013

Yes, my build is intended to be outdoor-ready, though I may use it indoors for awhile. I'm having difficulty with obstructions to the SSW direction, so getting it on the roof might help.

For the UHF reflectors I have a hunting/target arrow (fiber/graphite) wrapped with aluminum foil. I was planning to just use 2 vhf reflectors.

And yes, I love the snap-on t-fittings. I cut off about 40% on the bandsaw and they work wonderfully.

The single T standoff just seems "wobbly", so that is where I was thinking about supporting both ends of the reflectors.

I was thinking to give 1/2" pvc a try -- thinking the framework will add rigidity. 1/2" is $1.59/10' stick and fittings are $2-$3 for a pack of 10.

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