i run an astroplane myself. great antenna.
i guess nylon would work ok. the thing i would worry about with different plastics is static.
i dont know if nylon is "staticy" or not, just something to think about.
also, you have to consider the effect of UV rays on different plastics.
PVC will crumble in your hands eventually.
delrin is the best thing to use.
you can get all kinds of different diameters on ebay.
just do an ebay search for "delrin rod" and you will find what you need.
a two foot piece should be perfect.
shouldnt cost more than 20-25 bucks.
if the coax you are getting is the thick stuff (RG8 size .405" dia.) then you dont want to coil it around a form less than 8" in diameter.
if its LMR400 that you are getting (thats what i use. it cost more than my antenna, but its worth it!) then you will find that even 8" might be too small.
if you are getting something sized like RG8x (.242" dia.) then a 4" form should be fine.
AMPHENOL is a brand name and any place that you get your coax from that is reputable will most likely be using that brand of PL-259 connectors.
save yourself the headache and let them put the connectors on for you.
where are you getting your coax from and what kind?
remember about the grounding, that you cant run a ground wire from the antenna feedpoint to your groundrod as you will defeat the whole purpose of isolating the antenna from the mast and the coax.
i will lay out what the ideal setup would be, and you can adapt it to your situation.
ok, get a piece of delrin about 2 feet long that is the same diameter as your mast. (probably 1 1/4") turn the last 8-10 inches of one end down enough so it will sleeve into the top of your mast. drill two 1/4" holes 90* off of eachother through the mast and delrin rod and bolt it in place.
mount your RF choke somewhere within a foot or so of the feedpoint.
(BTW that 18-21 feet thing is for 160-10m, for CB you only need about 8 feet)
mount the antenna and GPK to the delrin rod.
now your mast and your coax are isolated from RF.
run the coax down to the ground rod.
you can either mount the polyphaser right to the ground rod or put it in a little plastic box within a couple of feet of the rod and just run a big ground strap from the polyphaser to the groundrod.
you must protect the polyphaser from the weather.
screw your antenna coax into one end of the polyphaser and screw one end of another length of coax into the other side of the polyphaser and run it to your radio. (yes, you need to order two separate pieces of coax)
now the lightning only has one path to your station and its through the polyphaser.
connect your antenna groundrod to the house electrical ground.
(one ground rod is the bare minimum. many people use three or four, about 8 feet apart, all tied together with ground strap)
round wire is not the best thing to use for grounding. (look up "skin effect")
flat copper strap is better.
ok, that should do it.
if you do that, you are doing pretty much everything you can to reduce the noise interference, and you have also increased your antenna's efficiency to boot!
can you tell from the length of my posts that im at work too? LOL
take it easy and good luck,
LC
