[TowerTalk] Yagiis

[Jim Lux]

At 06:26 PM 6/1/2007, Tom Rauch wrote:
>What's the latest thought on Yagi antennas?  Is the old work
>by Lawson on Yagis still considered accurate so far as boom
>length, number of elements, and gain?

One might want to try using one of the optimizing programs out there 
that use numerical modeling. 4nec2 is free, uses the NEC2 (or NEC4) 
engine, and has an optimizer that works fairly well.

This is especially so if you are making different tradeoffs for 
things like F/B, bandwidth, gain, and manufacturing 
tolerances.  There are some high gain designs that are exceedingly 
sensitive to small changes in dimensions, and modeling will help you 
avoid them.

Investing the few hundred bucks to get a copy of NEC4 is probably 
worth it, if you are serious about modeling. It does much better on 
cases of interest for hams (tapers, close to ground, angled connections)

Jim, W6RMK