I was also on vacation recently and tried a quite
different type of antenna -- the "double hula."

Basically I used each hula hoop as one arm of a
dipole, fed with 450 ohm ladder line, and energized
with an FT817 with 30w final amp. The antenna was up
approx. 16 ft.

On each hoop was wound 30 feet of copper wire. When
the two hoops were mounted so that each was
perpendicular with the ground, and each the same
distance above the ground (kinda like a horizontal
dipole -- and both were in the same plane) -- I
connected the wire on each hula hoop so that it made a
continuous helical circle (with no break) to which I
connected each side of the ladder line () ()

I loaded it with an Elecraft T1, obtaining a 1:1 SWR
on all bands 10-80m except for 17, 20 and 40m where
the SWR was between 1:1 and 1:2. Not too shabby. Had
contacts on the East Coast from Calif. on 20m.

I tried a lot of other configurations, but the best
alternative was where the hula hoops were still
perpendicular to the ground but this time were one on
top the other in the same plane, and this time the
wire on the hula hoops wasn't continuous -- there was
a break in each one (at the points where the hoops
came closest together). So on each hoop the ladder
line was connected to one side of the break. Again I
had 1:1 SWR on all bands except 17, 30 and 40m where
the SWR was between 1:1 and 1:2 (using the T1). Had a
few contacts on 20m with this antenna as well.

The downside was that I was running in and out of the
cabin so often to change the configs that I kept
hitting the metal roof with my head. There are now 3
nice healing cuts up there!

I would love to have more time to see what lengths of
copper wire would work best with the hoops, and to see
how they'd perform at 50 ft. up. Also, to figure out
what their propagations patterns are.

If they were used for pedestrian mobile, it's look
like the user had Mickey Mouse ears ....

-- Bil Paul KD6JUI


This antenna sounds interesting. I wonder how one would model it in
EZNEC demo...

--
73 for now
Buck
N4PGW

On Tue, 14 Jun 2005 15:37:51 -0400, Buck wrote:

This antenna sounds interesting. I wonder how one would model it in
EZNEC demo...

Hi Buck,

As a resistor.

73's
Richard Clark, KB7QHC

Carbon, or Wire-Wound ? :) Jim NN7K

Richard Clark wrote:
On Tue, 14 Jun 2005 15:37:51 -0400, Buck wrote:


This antenna sounds interesting. I wonder how one would model it in
EZNEC demo...


Hi Buck,

As a resistor.

73's
Richard Clark, KB7QHC

"Buck" wrote in message
...
I was also on vacation recently and tried a quite
different type of antenna -- the "double hula."

Basically I used each hula hoop as one arm of a
dipole, fed with 450 ohm ladder line, and energized
with an FT817 with 30w final amp. The antenna was up
approx. 16 ft.

On each hoop was wound 30 feet of copper wire. When
the two hoops were mounted so that each was
perpendicular with the ground, and each the same
distance above the ground (kinda like a horizontal
dipole -- and both were in the same plane) -- I
connected the wire on each hula hoop so that it made a
continuous helical circle (with no break) to which I
connected each side of the ladder line () ()

I loaded it with an Elecraft T1, obtaining a 1:1 SWR
on all bands 10-80m except for 17, 20 and 40m where
the SWR was between 1:1 and 1:2. Not too shabby. Had
contacts on the East Coast from Calif. on 20m.

I tried a lot of other configurations, but the best
alternative was where the hula hoops were still
perpendicular to the ground but this time were one on
top the other in the same plane, and this time the
wire on the hula hoops wasn't continuous -- there was
a break in each one (at the points where the hoops
came closest together). So on each hoop the ladder
line was connected to one side of the break. Again I
had 1:1 SWR on all bands except 17, 30 and 40m where
the SWR was between 1:1 and 1:2 (using the T1). Had a
few contacts on 20m with this antenna as well.

The downside was that I was running in and out of the
cabin so often to change the configs that I kept
hitting the metal roof with my head. There are now 3
nice healing cuts up there!

I would love to have more time to see what lengths of
copper wire would work best with the hoops, and to see
how they'd perform at 50 ft. up. Also, to figure out
what their propagations patterns are.

If they were used for pedestrian mobile, it's look
like the user had Mickey Mouse ears ....

-- Bil Paul KD6JUI

=====================================

Without wishing to be too despondent, it appears you have proved the
rule -almost anything will radiate. Interesting and well-described
nevertheless!
----
Reg, G4FGQ