If you can get a copy of the November, 2005 "World Radio", check out
"Kurt N Sturba"'s column, under "Aerials", on pg.55.-- he no dummy
when coms to antennas, ect, and hides behind that nome d'plume to avoid
conflicts with finger pointers. Tho on these antennas, a couple hundred
words, but informative. In essence, he sez that these are very lossey,
That a dipole (66 ft) on 40 meters would have a given bandwidth, IF
the Isotron had the same effeciency for it's size, it would have a band-
width of about 11 KHz. What it really has is a bandwidth of around 400
KHz this results in a signal about 2 "S" units , or 12 dB down from
THAT reference dipole. In other words, there are better more effecient
ways of radiating a signal! As information-- Jim NN7K




Dave Oldridge wrote:
I've been seeing pictures of these weird antennas for years. Near as I can
tell from the picture, it's essentially a heavily-loaded very short dipole
with two large capacity hats at the ends. But it's impossible to tell from
the pictures what the exact configuration is. Can anyone tell me exactly
what's happening? Is the mast part of the radiating system? The feedline?
The literature (including the manuals) sort of implies that it is.

Also, from the pictures, I get the impression that the standard mast-mount
configuration is mostly vertically polarized. This would certainly account
for reports I have read that the antenna is a bit of a dud at short range
on 80m.

If someone has a computer model for it for MMHAMSOFT's modeller, that would
be GREAT!

The reason I'm asking is that I'm in the process of trying to design
something really low profile for a second floor apartment balcony for 75
and 80m.