[TowerTalk] add a 3rd el to 40-2cd

[Tony Brock-Fisher]

I replaced a 40-2cd with a scratch-built copy of the W6NL Moxon. 
Although I was replacing a 2-element antenna on a 22 foot boom with 
another 2-element antenna on a 22 foot boom, It was a night and day 
improvement!

-Modeling suggests as much as a 4 db improvement, due to the elimination 
of lossy coils and better directivity from the longer elements and 
better current distribution.

-On the air performance supports this level of improvement.

-SWR is under 1.5:1 across the entire band. A 40-2CD tuned for CW is 
over 2:1 in the phone band, or vice versa. The improvement in SWR 
translates to being able to instantly QSY across the band rapidly with a 
manual-tune amp, instead of having to have a more expensive auto-tune 
amp to handle the changing load.

-The W6NL Moxon is less wind loading than a 3-element.

Others have built the W6NL Moxon and gotten similarly spectacular results.

-Tony, K1KP

email me off-list if you want more details.