Buck wrote:
Cecil Moore wrote:
I've added a Smith Chart graphic to my All-HF-Band-No-Tuner-Antenna
information on my web page.

I finally got to see the picture. Earlier, it loaded so slowly I only
got to see the top 10% after ten minutes or so.

QSL.NET is notoriously slow. I'm going to get a new web page supplier
one of these days.

If i read it correctly, you are saying that by adjusting the feedline
length, you have a 50 match at any band.

Close - by adjusting the feedline length, I have between a 25+j0 ohm
and a 100+j0 ohm "match" on any HF ham band. Any purely resistive
impedance between 25 ohms and 100 ohms will yield a 50 ohm SWR less
than 2:1. Most transmitters are satisfied with an SWR of less than
2:1. Any 450 ohm SWR between 4.5:1 and 18:1 (in the green zone) will
yield a 50 ohm SWR less than 2:1 if the proper length of feedline is
chosen.

It sounds like this antenna and feed match....

It is a tuned feeder that tunes the antenna system to resonance. To
get a 50 ohm SWR less than 2:1, the dipole needs to be 1/2 wavelength
on the lowest frequency of operation. That makes virtually all antenna
feedpoint impedances fall within the green target zone.

For instance, this feedline length adjustment will not work on a 102
ft. dipole (G5RV) used on 80m. The low R and high X causes the 450
ohm SWR to be higher than 18:1 so a 50 ohm SWR of 2:1 is impossible
without a tuner or network.

Here's the math:
450/18 = 25 ohms 50/25 = 2:1 SWR at current maximum point
450/4.5 = 100 ohms 100/50 = 2:1 SWR at current maximum point
--
73, Cecil http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----