Dave Platt wrote:
What if you are using a design plan exactly with the same diameter
material but with different material, say conduit instead of copper?

I would expect that the tuning would not change appreciably. The
antenna's losses might be higher, but likely not enough to be
noticeable.

If you direct connect an so connector. How do you adjust both sides?
I
mean once the ground is in place it is hard to adjust the "hot" side
unless you bend the wire alot.

You experiment a lot.

Maybe you build a bunch of antennas with different attachment points,
and measure them out. Or, maybe you cut one copper-pipe J-pole,
don't actually solder the pipes together yet (just depend on a
friction fit while tuning), drill a spiral pattern of holes or a line
of holes in the pipe to which you can try screwing the SO-239, and
try
a bunch of positions until you find one which works best. You then
rebuild the antenna with a new piece of pipe which is drilled for the
socket in only one place.

Or, you build a mounting-and-grounding bracket arrangement which
allows easy tuning... as is shown very clearly in one of the two sets
of plans I referred you to in the post you're replying to.

Like I said, the easiest way to get a working antenna is to exactly
reproduce a known-working example. If you want to vary the design,
you'll need to experiment, cut-and-try, and be willing to make
mistakes and learn from them.

--
Dave Platt
AE6EO
Hosting the Jade Warrior home page:
http://www.radagast.org/jade-warrior
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It is just I have some conduit and I can weld it. I thought is would be
interesting. I was thinking of building one of those "slim jims' but
think the mounting might prove to be a problem.

I am wanting to build a j pole, an arrow antenna type open stub, and
maybe a ground plane just to see if there is any difference in them
using for simplex and repeater operation. I eventually want to build a
yagi for 440 and compare it to the dual band open stub j pole like the
arrow.

I am just so confused over this j pole. So many people have different
opnions. One says it should never be grounded or touch a metal mast
others say it does not matter. SOme say it should use a choke of some
type others say it does not matter. It is confusing. What do you think
on that? I guess my uneducated opinion is it should be insulated and a
few turns of coax used as a choke but this is just that the people on
that side of the argument seem to be more convincing and some have doen
models on nec but I really do not know.