[Antennas] Re: Removing the inner from coax.
Barry L. Ornitz
[email protected]
2003年8月23日 19:45:50 -0400
Chris, VE7HCB, asked:
> Some questions on the fibreglass.
> Drilling with carbide bits suggest cutting with carbide
> blades, True?
Yes. Fiberglass will dull steel blades quite quickly.
> How can they be joined together to form a long whip etc?
Probably the best way is to fabricate a short section of
fiberglass tube that will just telescope over the rod. For
strength, this tube should have a cross-sectional area at
least as large as the rod over which it telescopes. This can
be glued in place with epoxy (preferably the 24-hour type
which is stronger and more flexible than the rapid cure
varieties that are brittle). However, the finished product
will not be as strong as a continuous fiberglass rod.
Continuous fiberglass whips are available up to at least 33
feet (Shakespeare used to make marine antennas from these).
For fiberglass spreaders and other supplies, I generally refer
folks to my friend Alan Bond at Max-Gain Systems.
http://www.mgs4u.com/index.html
> One suggestion for the plastic spreaders was to heat the
> wire at point of contact with spreader and wire taut, it
> will melt its way into the spreader and close the gap
> behind it. Anything similar with the fibreglass (solvent?)?
Most resins used with fiberglass are thermoset varieties.
Typically an unsaturated polyester resin is used, but epoxy
resins are common too. Thermoset resins do not soften with
temperature. Likewise they are solvent resistant.
The big advantage of fiberglass is its high strength. It is
therefore quite handy for end insulators. As a feedline
separator, it is probably overkill.
73, Barry WA4VZQ [email protected]