"Art Unwin" wrote in message
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On Jul 11, 2:32 pm, "Wayne" wrote:
"Clark Kent" wrote in message

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"Art Unwin" wrote in message

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Tell you what, get some wire twice the WL of the frequency you are
interested in.
Wind a close coil any diameter with it until half the wire is used
then change direction and come back
without changing wire winding direction and wind the wire on top of
the first coil where you finish with two wires to feed.
Put a variometer in series with it and then get on the air. Now this
is not exactly in equilibrium because one coil is a larger diameter
than
the other. Nor is the wire pre twisted pair which nullifies near
field
noise to my thinking. Now you have a helix style antenna but without
the helix.
Coat the antenna with an alkyd type solution before you slide it off
the tube since the inside coil must be exposed the same way the
outside coil is exposed

OK, I can do most of that. However, I went to your page for some
variometer
details, as I don't have one. No luck. From other reading it appears
to
be
a loosely couple balun or un-un. But near there on your page, I
discovered
some verbiage about building an antenna and saw the reference to a
12-inch
diameter. Good find, as I was going to go smaller.

If I wound the thing on cardboard (like a big empty ice cream tub from
the
ice cream store), could I avoid having to take the coil(s) off the
form?
What about a paint bucket or an empty pool chlorine tub? I'd sorta
like
to
skip that alkyd step. Messy.

Need more variometer data, but I'll dig for that

I thought I might try and experiment with building one, since it seems
simple. The variometer is a deal killer however. Is there any reason a
transmatch/balun couldn't be used?

The variometer allows the frequency to be moved as a multiple of a
wavelength.
Thus allows your antenna to vary as you turn the knob on the radio.
If you do not use a variometer then you just have to hope that one of
the many suitable swr points rest
upon your frequency of choice. This can also be simulated by a series
of jumpers or a slider method
over the surface of the windings. For me I prefer a variometer since
the motor drive can be that which is dismantled from the radio's tuner
such that you have an automatic set up the same as the new variable
antenna that hit the market a few years ago except this design
is less than $100.....big difference.......and much much
smaller....... and yes the variometer is placed on the top of the
tower with your 160M
rotatable antenna. Don't know where I will go next! Sweaty...need a
shower
Unwinantennas.com/

Suddenly, here's just a TON of stuff that needs some good sense sprinkled on
it. Just a few highlights:

I just took another look at the website and further examined the graphs at
the bottom. Per your instructions, using approximately 2000 ft of wire
means the antenna is wound for a wl of 1000 ft, 305 meters or around 1 MHz.
How is it you're getting a decent SWR nearly everywhere from 1.0 to 100 MHz?
Look, the WORST number for SWR is about 4:1, well within the range of any
decent tuner. BTW, it looks like the response of a comb filter, except
that the cancellation frequencies between the reinforcements don't look as
lossy as they should look.

The variometer will do variable transformer coupling. OK fine, but I think
you should have provided a description for one. The link to
http://www.qsl.net/in3otd/variodes.html was instructive but ... I have no
idea what coil inductances to shoot for. Groping in the dark is not fun.

What does it mean to move the frequency as a multiple of wavelength?

What does it mean for the antenna to vary as I turn the knob on the radio?
I've got decades of experience with this hobby and that does not compute.
You shouldn't throw this stuff out and figure we're mind readers.

160m rotatable antenna? I don't travel in those circles. If that was a
joke, I guess I need my sense of humor recalibrated.

Here's my own "tell you what": I'll wind one of these things for 20m, which
isn't a lot of wire. I have an antenna analyzer that will tell me a few
nice things about what I have.

Then if the SWR is anything like reasonable, it's Kenwood Time! I'll check
for who I can hear and try working him. ... and I'll check for WWV on 15.
I can usually hear him any day, often on a cheap portable radio with a whip
antenna.

Using a local ham (eliminating the bulk of QSB) I can compare antennas for
equal S-meter readings with a switchable attenuator in line with the better
antenna.

That will settle it for me.