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24-09-2017, 08:12 PM
I plan on making a few antennas in the future that will require a insulator to fit into some aluminium tube that will be suitable for RF.
I am wondering what would be the best type plastic to use?
Some options are
HDPE
Polyurethane
Acetal Delrin®
Teflon
Acrylic
Nylon
And possibly more in many colours.
This site shows a good range of options
http://stores.ebay.com.au/Warlond-Plasti...7675.l2563
As I have a lathe I will be able to machine to the correct size but I want to make sure the insulator is suitable for RF and UV.
Thanks
Michael
VK6TU
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Hi Michael,
You can test plastics for rf compatibility by putting pieces in the microwave for a few seconds or longer.
I presume the results can be extrapolated down to vhf or hf. But I stand corrected.
Remember that nylon is hygroscopic.
I don't know about uv resistance though. Black plastics could be an indication.
Nev
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Joined: Dec 2016
(24-09-2017, 08:52 PM)VK3LU Wrote: Hi Michael,
You can test plastics for rf compatibility by putting pieces in the microwave for a few seconds or longer.
I presume the results can be extrapolated down to vhf or hf. But I stand corrected.
Remember that nylon is hygroscopic.
I don't know about uv resistance though. Black plastics could be an indication.
Nev
Nev,
Thanks, Have used a microwave before to test unknown plastics, the only problem is I no longer own a Microwave and more importantly I have not got the plastic yet, prefer not to get some if its not suitable, that's why I asked
Thanks for the tip on Nylon, its off the list.
73 from Michael
VK6TU
Polycarbonate is another option. Reasonably strong and relatively immune to UV.
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to "fit inside Aluminium tube".
I'd suggest fiber-glass rod as in electric fence posts, see your local Produce Store.
Here on 6m and 2m beams, I use PVC 1/4 inch sheet cut into small squares or rectangles
screwed onto the (note square) boom and round elements with stainless screws.
Everything is at low voltage. Life in the sun, 30+ years.
Another plastic of use: Recycled plastic garden stakes.
Screws, forget Bunno's, find a real nut and bolt supplier and buy boxes of 200 8G x 3/4 for about $7 a box.
There are various grades of stainless-steel. 316 grade is much dearer than 304 and harder
to work. For antenna we only need 304.
You can, after filing, solder to the stainless screws. (proper flux though, Chemtools VIOFLUX)
