In message , Ralph
Mowery writes

"Brian Howie" wrote in message
...
I did a simple sagging 40m dipole on MMANA using the wire editor with
9 wires. I had a 3m sag in the middle . I ran the optimiser for best
match. The impedance worked out at 69 ohm and the gain was 2.06dBi. The
model reported a lobe elevation of about 8 degrees. There was a
vertically polarised component at 90 degrees to the horizontal lobe
at -15dBi.


I know you did that for an example, but 3 meters of sag for a 40 meter
dipole is a lot of sag. I bet the ends were close together.
About 1 meter of sag would be more like it.

Yes it is a lot of sag. It's 19.57m end to end. The unsagging one is
20.81, so there's more wire in the sagging one. Recall I altered the
length to get a good match. If you had a sagging dipole like that you'd
have to trim the length.

For a 1m sag the vertical component is below -60dB and it's close to
the unsagging performance.

I was interested in the catenary problem for a different reason.

http://www.bigskyspaces.com/w7gj/longyagi.htm

I toyed with the idea of making one of those at one time.

Brian GM4DIJ

--
Brian Howie

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com