At 08:57 AM 12/4/2006, Don Havlicek wrote:
>Why not use copper tubing which is available at those 'despot' type stores?
>Copper is much easier to work with [and solder taps where needed] than
>aluminum.
And MUCH more expensive. Aiee.. I just bought some 1" pipe elbows $4-5 each!
I'm keeping that 100 ft spool of tubing hidden away.
>Don
>N8DE
>
>Keith Dutson wrote:
>
> >Why not make the coil from small aluminum tubing without leaving the form in
> >place? It would be easy to adjust.
> >
> >73, Keith NM5G
> >
> >-----Original Message-----
> >From: towertalk-bounces@contesting.com
> >[mailto:towertalk-bounces@contesting.com] On Behalf Of Dan Zimmerman N3OX
> >Sent: Monday, December 04, 2006 10:42 AM
> >To: towertalk@contesting.com
> >Subject: [TowerTalk] Grey PVC Loading Coil
> >
> >In the spirit of "some antenna is better than no antenna at all," I'm going
> >to add a base loading coil to for 160m to my 40 foot vertical
> >(http://www.n3ox.net/projects/lowbandvert).
> >
> >I know it's a substantial compromise over other forms of loading, but I'm
> >willing to accept the efficiency penalty for convenience in this particular
> >case. What I want to know about is whether or not grey PVC electrical
> >conduit is suitable for coil forms at 1.8MHz. I searched the archives and
> >found a discussion on PVC formers for HF and that they're not unacceptable
> >unless you're running many close-spaced turns, but I wonder if people have
> >tried grey vs. white and what they've found. I know the microwave trick is
> >routinely used but I don't think absorption at 2.4GHz says much about the MF
> >properties of the material.
> >
> >I've got access to some 5" conduit and a lathe; a few minutes and I can have
> >a beautiful coil form like the 80m one on the page above, but I wonder if
> >the grey PVC is lossier than the white stuff?
> >
> >There are plenty of other approaches, but if grey PVC is decent at 1.8MHz,
> >I'm just going to cut a nice groove in it and go. It's going to be
> >something like 20-30 turns of #10 wire and having a grooved form makes for a
> >quick and solid coil.
> >
> >73,
> >Dan
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