[Antennas] 15M beam construction?

2003年12月25日 17:26:56 -0600

>I have a 3 el CushCraft tribander, which I would like 
>to convert to 15M monobander.

Sounds like a fun project to consider there! My first
homebrew yagi was a 4L 15m yagi, which I then made
into a 3L that actually worked better with less elements.
>If i take out the traps, and add some length, wold this 
>be a feasible project, or should I start over?

Off hand, the 3L15m yagi is roughly the physical size 
of many of the more standard tribanders, so you are
off to a good start with this already. Excellent!
>Where would you recommend I look online for a plan 
>for a 3 el 15M beam/dimensions, etc. 

Some possible sources:
Various editions of ARRL Antenna handbooks
Hygain website ... download their 153BA manual
Cush Craft website ... download their 15m monobander manuals
Force 12 ... their designs are very solid, but the data is copyrighted.
W6NL wrote an excellent book on yagi design, not sure
if it's still in print or not though. Check the ARRL site ...
Also consider articles in QST and CQ over the years with 
various ideas and construction methods ... 
You'll reach a point where the information may seem to be
overwhelming ... Do I build this for gain? For F/B? For SWR?
In reality ... you will learn a lot about how yagis really work
and how compromises, even with monoband designs are
also a reality.
May the above prove useful in some form or fashion!
Season's Greetings,
73 Billy AA4NU