On Sun, 8 Nov 2009 11:25:01 -0600, "amdx" wrote:

I'll try to get a better picture of the feedpoint for you.
Is there a way to work the .66 wavelength of 50 ohm cable backwards ie.
What impedance would be transformed to 50 ohms with .66 wavelength of
50 ohm coax?
(this assumes the little knowledge I have about impedance transformation
using
coax is correct.)
Mike

Here's a link to a picture.
http://i395.photobucket.com/albums/p...MFJCollage.jpg
Mike


Hi Mike,

That is a pretty good rendering given the other pix. Have you any
experience with Smith Charts? Still, and all, you need to know the Z
of at least one point to transform to another.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Sun, 8 Nov 2009 11:25:01 -0600, "amdx" wrote:

I'll try to get a better picture of the feedpoint for you.
Is there a way to work the .66 wavelength of 50 ohm cable backwards
ie.
What impedance would be transformed to 50 ohms with .66 wavelength of
50 ohm coax?
(this assumes the little knowledge I have about impedance transformation
using
coax is correct.)
Mike

Here's a link to a picture.
http://i395.photobucket.com/albums/p...MFJCollage.jpg
Mike


Hi Mike,

That is a pretty good rendering given the other pix. Have you any
experience with Smith Charts? Still, and all, you need to know the Z
of at least one point to transform to another.

73's
Richard Clark, KB7QHC

They should have been better, those are pictures I took a couple of years
ago.
I didn't blowup someone elses pictures.
"you need to know the Z of at least one point to transform to another."
I would be happy with the assumption the the impedance at the N connector
is 50 ohms. But I think I have a misunderstanding because, in use you would
add more 50 ohm coax to run from the N connector to the transmiter. Soo,
that .66
wavelength section on the antenna becomes anything you add to it.
AT this point, I have to think the folded loop is forced down to 50 ohms by
it's
surrounding structures and there is no impedance transformation betwen the
loop
and the N connector.
Mike