Hi Joe,
>
>> I've shunt fed my EZ-Way RBZ-66 in its lowered position (TH11 at 40',
>> 402BA at 50') and it works very well.
>
>By lowered position, do you mean cranked down somewhat? I'm not
>familiar with EZ-Way RBZ-66.
Its an old model, 66' extended, 30 some odd totally retracted. It's matched
at the 40' level for 80 and 160. 80 works great, 160 is fair due to its low
height.
>
>> Fairly easy to build and install a linear loading cage with either a
>> gamma or omega match. I use separate cages for 80 and 160.
>
>Been looking at ON4UN's new book and ARRL Antenna book and see
>the simplicity of it. I would also go for 80 and 160, separate cages.
>I have the Pro57-B at 95 ft and 40 2-CD at 105 ft, would this be too
>much top loading, do you think?
Yours should be easier to match than mine since your tower is closer to a
quarter wave on 160. In fact, with top loading, the electrical height may
exceed a quarter wave. Cant remember where the chart was that gave tower
heights and types of antennas to give the electrical height. May have been
ON4UN's book. Try experimenting with different heights of attaching the
loading wires. If you just want to do it and be done with it, pick a height,
then try gamma matching first, then if that doesnt work try omega. Others
more astute than myself can help you figure the perfect resonace point based
on height of the loading wires and what equipment is needed to measure it.
In my circumstance, I wanted to have the tower in a lowered position and not
worry about 70 mph wind at -20 F.
>
>A point that bothers me is the coax feed to the RCS8-V ant switch and
>coax to a 2-meter ant, plus control lines for rotator and RCS8-V. Book
>says these need to be inside the tower. For a crank-up, this looks
>mighty tricky.
>
All my coax and rotor cables are on outside the tower. Actually debated
routing cables on the inside, but opted not to because of the crank up
issue. Side mounted to the tower is a Top Ten devices antenna relay switch
box, and a 2 meter Ringo packet cluster antenna. When transmitting, the
rotor control box is turned off. The packet radio stays connected to the
cluster. To this point with 1400 watts, there are no adverse effects.
Although, there has to be current running on the shield with this setup. I
plan to eliminate it with coaxial wound chokes for the transmission lines
and beads for the multi-conductor cables. Actually, I'm in no hurry since it
works like a champ.
Mine is a very simple design. Have a length of 3/4" alum tubing running @54"
out the side of the tower with a solid 3/8" rod slid through the center,
forming a "T". The tubing is held to a horizontal brace of the tower with
hose clamps and bonded to the tower and tube with 12 gauge copper wire and
noalox. Three 10 gauge wires run down the tower at a spacing of 18" from
each other and 36" from the tower, and are held taught by a similar design
to the top, but all made out of pvc pipe. The wire is held to the pvc with
hose clamps as well. The 3 wires come together approx 12" off the ground and
are routed to a water tight box side mounted to the tower at the 3' level.
There are 2 of these contraptions, 1 for 80 and 1 for 160. The 160 uses an
omega match, 80 uses a gamma match. For simplicity, 1 cage would work if you
switched the caps with a relay. For me, 2 cages were the simpler design. The
cage design provides greater bandwidth. It has 60 khz on 160 and 150 khz on
80. They have been up 7 yearsand proveded 80m DXCC and well on the way to
160 DXCC.
Hope this helps. As usual, more detail can be given if desired.
73,
Bob, K3GT
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