"Richard" wrote in message
...

"Tam/WB2TT" wrote in message
...

"Richard" wrote in message
...
Is anyone engaged is a design philosophy that seeks the design of VHF
yagi's
with the smallest acceptable diameter of elements?

What you are trying to do is to design lighweight VHF yagis, you are
seeking
how small you can go with element diameters before performance begins
to
suffer.

Richard,
I think if it is heavy enough to physically support itself, it will be
electrically OK. This turns out to be about 1/4 inch (6 mm) tubing at 50
MHz, and 1/8 inch (3mm) hard aluminum rod at 144 MHz and above.

Tam/WB2TT

Thanks. Of course over the years I'm used to seeing commercial TV and FM
antennas which tend to use 3/8" and greater for elements and because just
recently I've been comimg across designs using 4mm tubing it seems odd to
me. As if there's just got to be some big losses or compromises on using
say 4mm dia rod. But I now see that quite standard of course to use 3 and
4mm elements for high band VHFyagis. All is rather new to me. I should be
seeing 4mm rod as the norm for a VHFhigh band yagi.

Some of the variation in the size of tubing seems to depend on the quality
of the tubing used. Any ham antenna I have seen uses seamless fairly hard
alloy, whereas some TV antennas use a larger diameter rolled (if that is the
right term) tubing of very thin material.

Tam/WB2TT