>If anyone has by chance successfully optimized the Hy-Gain 5el Long John 20,
>15 & 10m yagis for maximum GAIN ONLY (vs. a Gain & F/B balance), I'd sure
>love to chat with you.
Yo Locust
Not sure about the "successfully" part but I have been using the mods
for the Long Johns.
Hy-Gain charts and others show "Max Gain" designs but the plots show
almost no real improvement which is quickly swamped out by the real
world. Gain is by boom length so you really can't do much there although
there usually is a little upward trend towards the high side on 15 and ten.
I have been building Long John 10's/15's all summer and switched from
the Hy-gain chart to N6BV design using YW. They are also in the ARRL
antenna book. His design which is the best compromise of all the variables
allow very good max gain and pattern. They also have excellent SWR over
CW and Phone which is what I was looking for.
The N6BV design requires a balance offset by about 1 foot to be recovered
by counter weights.
I did a lot of tuning of these antennas in stacks. This was with a lot of
up/down
of the antenna using a rope and making small adjustments. I stopped using the
MFJ and went to 10 watts from a 746 radio so I could get solid repeatability.
The Beta match was always about three inches too short and the driven element
about 1/2 inch too long once I found the correct adjustment. There is a 1.2 to
1 sweet spot somewhere in the match, you just have to find it.
I kept the 155's at 30 feet separation and the 105's at 25 feet in the final
stack. I
also ran tests with the Hy-gain 5 element 10 meter close to a 24 foot boom six
meter yagi and didn't detect any interaction within 5 feet.
I have identical stacks using Cushcraft 4 element antennas. I just install then
in
the stack location and can reach the gamma rod to adjust them in seconds.
73 Rich KL7RA
p.s. Oh, want more gain for the 205? Use a 40 foot boom, I did.
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