For the past week on 160 meters I have been agonizing over the inability
to be heard in Europe. My 500 foot east Beverage has been a thrill to
listening to but calling RA3DOX for an hour and still no qso has not
been. I was able to squeak out a 239 report from G6VZ and got RA6AX to
call me Bruce and identify me as K1FZ! Even DF2PY with his booming 599
plus signal could not hear a peep from me. Wolf has a superb location
and a very fine setup.
I did manage a 449 report after many call from ZS6UT and a 449 report
from IV3PRK after calling him for over an hour. So what is the problem.
I use in the TX department a 76 foot Rohn 25G (68 feet with a ten foot
pipe on top.) 20 radials, half of which are #6 bare copper 130 feet
long and laying on flat soil of fairly good conductivity. A brackish
water table is only 10 feet below the surface since I live next to a
large salt pond lake (Its called Great Salt Pond) The other radials are
long pieces of insulated #2 wire of various lengths 50 to 60 feet long
which also lay on the ground. The tower is shunt fed with a #6 copper
wire separated about 24 inches from the Rohn 25 G and tapped at the 40
foot point. An L network with a broadcast TX flat wound coil and a
500pf 15 KV vac are used to do the match. I have a 1.5 to 1 SWR over 20
Khz of the low end near 1.830.
The TX performance has been disappointing, until:
yesterday when I decided to mount the 26 foot boom, just the boom, of an
uncompleted 204 BA on top of the pipe which extends out of the tower.
The low point of VSWR dropped to 1809 Khz indicating I had done
something to raise the radiation resistance slightly. I know it is not
very scientific but last night instead of calling eu stations endlessly
and if worked getting embarrassing reports it went like this:
SM4CAN 599 both ways on the first call.
G3XGC 589 on the first call.
ON7GR 579 on the first call
G4VGO 599 both ways on the second call in heavy traffic.
ON6AA 599 both ways on the first call.
The problems in getting to excited with this is that there was an
absence of Eastern European stations and propagation could have been
vastly different. Still I was very impressed by what a horizontal 26
foot piece of aluminum tubing appeared to do for me. I hope this is
more than just wishful thinking. I am working today on putting the
elements together from the remains to three major hurricanes in hopes it
will help even more.
Please let me know if you have had any similar experiences with some
simple top loading to a vertical making a huge improvement in radiation
efficiency and lowering the take off angle.
73
Herb, KV4FZ
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