160 contest aerials

Michael Mraz mikemr at microsoft.com
Thu Feb 4 19:40:10 EST 1993


Geoff writes:

WA1U multi-single
556/53/24 =110,264
We still have some editting to do so this total will fluctuate a bit.
500 watts and day 1 40 foot vertical with radial assist on top.  Day 2
(after much trouble) 1/4 wave balloon vertical.


I'm interested to know how many other people tried balloon-supported
antennas in this contest. I put up a 1/2-wave end-fed vertical under a large
weather balloon. We had perfect "ballooning" conditions (sunny and no wind)
until I put up the antenna, at which time a northerly blew my 
balloon-antenna into a
very large douglas fir tree. Now it's a permanent 1/2-wave end-fed 
kinda-sloper,
and the balloon is in shreds! It actually works quite well on 160, 80, and 40.

The second night, I tried it again, but with four 3-foot toy (rubber) 
balloons. They
started losing their lift at about 1000z (just after the aurora that 
killed the band up
here). Again, absolutely no wind until the balloons started to deflate, 
and then a little
breeze threatened the #2 antenna. I reeled it in and went back to the 
kinda-sloper.

I built a tuner with a motor-driven tuning capacitor, so that I could 
stick the tuner
wherever I wanted and drive the tuning capacitor from the shack to resonate the
LC network. It worked great except during the second evening when I noticed
bright blue flashes outside and smelled smoke. Upon examination, the antenna
wire had touched a piece of wood on the sawhorses that the tuner was 
sitting on,
and had burned about 1/4-inch into the 2x4. Amazing what a kW of RF will do!

See you in the Sprint    Mike    N6MZ    mikemr at microsoft.com



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