[Towertalk] 100M-long boom Yagi for 20M

K3BU@aol.com K3BU@aol.com
Tue, 14 Jan 2003 18:03:48 EST


Hi Joe,
thanks for the info and encouraging news about correlation with real life 
(2m) models.

Yes, it is interesting how many possible solutions there are within the 
antenna design, and how easy it is to miss that ideal configuration. So far I 
played with my 3 el. Quad design, and unless I start with my experimental 
design and then try to optimize it with AO (I get small improvement) the AO 
will take off and end up with some designs that are way off the "achievable". 
So it looks like it is very beneficial to start with some known good design 
and trying to improve it.

I am trying now do get handle on the modeling and optimization programs and 
go over my old Quagi - Razor designs. There is new (freeware) 4NEC2 program 
which uses NEC engine and adds optimization (generic algorithm) features and 
also MultiNEC, which allows import and export of designs between various 
software and also study the results over the range of parameters via Excel 
spreadsheet. Unfortunately I was very QRL in the past, but hopefully, now 
with cold wx I should have more time to get around to play with soft 
modeling/verification.

I think that my 7el. stacked Razors would also be very close to the 100m Yagi 
array. Will try to analyze and compare it in software. It is amazing what 
good (outrageous) antenna can do. Those who tried it, know it :-) What about 
(rota)floating curtain array over salt water?

73  Yuri, K3BU