"GeorgeF" wrote in message
...


F8BOE wrote:

Hello,

Just a simple dumb question: is it the "birdfeeder" that radiates or the
coaxial cable used between the transceiver and the miraculous antenna?

73 de F8BOE Olivier ...-.-


I belive its the two metal places, one above and one below the coil
which are to form a capacitor.

George

I seem to recall an indepth analysis on the AntennEx site showing that it
was the shield on the coax that did the majority of the radiating. A simple
proof would be to change the coaxial feeder length or how it is physically
run and look for VSWR changes.

Dale W4OP

I seem to recall an indepth analysis on the AntennEx site showing that it
was the shield on the coax that did the majority of the radiating. A simple
proof would be to change the coaxial feeder length or how it is physically
run and look for VSWR changes.

Dale W4OP

Originally where I had the 40 Meter Isotron located I was using about a
50' coax run (RF-9913). I the moved the antenna to a different position
and had to add about 25' more of coax. The additional coax caused SWR
to jump from about 1.2:1 to 1.4:1. A quick returning of the "tuning
rod" on the antenna brought it back to 1.2:1

Last night I was doing more playing with the 10/15/20 combo, was able
to get the 20 meter size down to 1.2:1 and had about a 300 KHz bandwith
to say under 2:1 SWR so I'm happy with that. But still can't get the 10
& 15 meters to do any better than 3:1. It possibly might be the
location of the ant as its pretty close to some electical house wiring?

George

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

"Dale" == Dale Parfitt writes:

[... GeorgeF asked about Isotrons ...]

Dale I seem to recall an indepth analysis on the AntennEx site
Dale showing that it was the shield on the coax that did the majority
Dale of the radiating. A simple proof would be to change the coaxial
Dale feeder length or how it is physically run and look for VSWR
Dale changes.

So if someone tells me about a crazy antenna that "just works" but
which relies on the feedline being straight and not coiled, I should
suspect it to be Isotron-like in design and effect?

Dale Dale W4OP

Jack.
(figuring someone with field-strength meters could solve this)
- --
Jack Twilley
jmt at twilley dot org
http colon slash slash www dot twilley dot org slash tilde jmt slash
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (FreeBSD)

iD8DBQFA+X4jGPFSfAB/ezgRAmcwAJ41qbL4qKwqFoQeT5X4DPow49nJUgCgvmmf
/uBNEl/heAnZpn1VwHjoAQc=
=8OqZ
-----END PGP SIGNATURE-----