Henry Kolesnik wrote:
What's a Cobra head?
"Buck" wrote in message
...
On Thu, 16 Jun 2005 09:56:24 -0400, "Fred W4JLE"
wrote:

That being the case, can I just keep folding back a 120 foot insulated
wire
dipole until it is say 5 or 6 foot long and it will still be resonant on
the original frequency?

"Dave" wrote in message
...
if it is insulated wire it must be cut, if its not then it doesn't.
though
you will see some effect of folding it back even with insulated wire it
won't be the same as cutting the wire shorter.

No one said it would be resonant on the SAME frequency, just that
there will be some effect. I have heard about an antenna design for a
shortened dipole using 3-conductor home electrical wire. At one end,
the green is connected to the cobra-head and the black and white wires
are soldered together. At the other end, the black is soldered to the
green. Viola -- a linear loaded dipole!

I haven't tried it, but if it works, you may very well get your
desired frequency with folded wire. I would strongly suspect it will
be a compromise antenna as opposed to one with a gain, though.


--
73 for now
Buck
N4PGW

As I recall it is a commercial name for a center insulator for the
common dipole. It was narrow at the bottom to accept the feed line,
and flared out at the top for connection to the dipole elements. With
the transmission line connected it sorta looked like the head of a
cobra snake. I haven't seen a cobra in person, nor have I saw a cobra
head insulator. I think I would like to keep it that way.
Gary N4AST