yes, this is a common problem. try checking out the arrl's radio direction
finding book for more specific techniques. but a couple simple ones are
1. a small loop, use the sharp nulls off the ends of the loop instead of the
big wide lobes.
2. a doppler system that electronically rotates antennas to give direction.
there is a very simple one on my web site at:
http://www.k1ttt.net/technote/doppler.html
3. a pair of phased verticals set up to give a cardioid pattern, again use
the sharp null not the fat lobe.

"Jim" wrote in message
...
This isn't strictly a Ham question, but I hope you all can help me anyway.

I am using small transmitters in the 166-167 mhz range in some Box Turtle
research I am doing. My RDF antenna is a 3 element Yagi designed via
Yagicad 4.1 which works pretty well. It has 48db front/back and about 90
degrees beamwidth in the H pattern.

This works well for initial locating......usually starting 1500 to 2000
feet
from my transmitter, but the closer I get, the more inaccurate it becomes.

What kind of antenna design could I switch to when I get to close range
that
would have a narrower beam so I could pinpint my target? It would be nice
to have something smaller than my 35" x 21" yagi for close in work, but
the
beam width is the primary concern.

Yagicad doesn't let me design solely on beam width (at least I haven't
figured out how) so is there another way to go on this??

Thanks
Jim