"Steve Nosko" wrote in message
...


Summarizing the other two posts and what you alredy know. With the
effects
of the surroundings the formulas won't be much good anyway.

Put the traps at the ends of the standard 75M dipole [["75m portion ...is
easy ..."]]. Make this a little long if U like. Add a little too much
wire
for the 160, then measure the 75M and 160M min SWR freq. Adjust the 75M
length for your 75M freq of interest. Then, using 468/F figure out how
far
off you appear to be on the 160 length. Trim off about 80% of that value,
then trim-by-SWR the rest of the way.

Sound good fellas?

[[personally, i think if ur 2:1 makes no diff at the other end]]]
--
Steve N, K,9;d, c. i My email has no u's.


That's basically what I did. I ran into an interesting issue tuning
the 75m portion - as I cut the antenna in shorter and shorter
increments as I approached my design freq, something wierd
happened - I was at 3.844 and cut 12" off each end which got
me 3.868. I cut another 6" and got 3.860? At that point I stopped
cutting. My traps were designed for 3.890 but I had no way to
measure them.

Why did trimming 6" lower my resonant freq 8 kHz? I'm guessing
but could my traps be closer to 3.86 than 3.89? I'm afraid to cut
more.

Here are the results I got:

Band 2:1 SWR range Bandwidth Center Best SWR
160 1.862-2.040 0.178 1.951.0 1.0:1
80 3.759-3.916 0.157 3.837.5 1.0:1

Ken KG0WX