Some of you in passing my place near Singing Hills on
Road #1 may have noticed things going on in the back ‘40’. Well, things were
going on. Last year during the ARRL 10M Contest I lost my rotator on the
125’ tower. I had swung southeast to see if anything was coming in from the
Bahaman’s. Oscar - CO2OJ in Havana had e-mailed me and indicated he’d be on
over that weekend. I didn’t find a whole heck of a lot in that direction and
when I went to swing the (then) KT34XA back to the East - nothing happened!
Hmmm, no directional antenna for 10M - what to do? I have a New Wave Antenna
26’ Portable on which I could erect my bamboo spreader, two element, 10M
Quad but that would take up time. I could erect a 10M vertical but that
could turn out to be an exercise in futility. So, I limped through the rest
of the contest with my 80M dipole loaded on 10M. I didn’t accomplish what
I’d set out to do that weekend (WAS on 10M, again) but it was a fun
exercise. The crux of the problem was ‘I needed a new rotator!’
For some time my KT34XA had been suffering from the typical KT34XA problem
on 15M - its most resonate point was 20 MHz. M Squared (M^2) in Fresno
offered a kit to upgrade the KT34XA to a KT36XA which they claimed would do
wonderful things for this triband, beam. I expended the $300 for the kit and
really was impressed with the hardware they offered in this kit. Very nicely
machined shorting bars to take the place of the flimsy aluminum straps with
which the beam original had come. The hardware was stainless steel with the
nuts being what are called ‘aircraft nuts’ or nuts that are manufactured
with a nylon insert which acts like a lock washer.
It must have been around June that I’d contacted Colorado Tower Work for a
quote. Jack and I haggle quite a bit but we did come to a meeting of the
minds. He has a crane service "Rocky Mountain Boom" out of Longmont with
which he works closely. And, I needed a crane that could boom up to about
150’ to do the job or removing the KT34XA from the 125’ tower.
It took a bit of precision work on the part of the crane
operator to remove the KT34XA and not bump the 2 element, 40M beam (402CD).
It finally reached the ground and I started my modification which took about
2 weeks and then to get it back up the tower we had to play the, "wait on
the WX game." Crossing my back ‘40’ with a 50,000 lb. crane could allow it
to become a permanent fixture if it were to sink in the damp soil of my bog.
The modification was a real chore. Not only did the shorting bars have to
be changed out but the capacitor tubes had to be changed out also which were
not an inclusion to the kit. M^2 wanted about $8 each for the tubes of which
there were 16 required, plus shipping from CA. I went to Home Depot and
acquired the same diameter and wall thickness tubing at $1 a foot which I
cut to the proper lengths on my band saw.
Once the modification was complete I attempted to check resonance points
with the beam about 6’ off the ground and saw that, at least, there was some
resonance’s where I wanted them - especially on 15M. Finally we got a break
in the WX and the tower climber was summoned plus the crane. It all went
together like clock work and the initial checks with the beam back in place
didn’t produce the curves that I would have like to have seen using the MFJ
Antenna Analyzer. Finally I connected the antenna to my HP Automatic Network
Analyzer and found on all three bands the Return Loss to be acceptable
across all three bands. On 15M the R/L was on the order of 12dB but
attributed that to an interaction with the 40M beam that resides above the
tribander.
"On the air" testing indicated a definite improvement over the old KT34XA.
The front to back ratio seem to be better and I am able to receive a
response from DX stations, in a pile up, with only one call from me - and
running only 100 watts. When running the Alpha amplifier I’m able to talk to
whom I want when I want, anywhere in the world.
In Summary, let me say that my objectives have been met: new rotator
installed, new rotator control cable installed, new transmission line (7/8"
Helix) installed, KT34XA modified and upgraded to a KT36XA and installed.
Monetarily, my wallet was lightened by about $3,500. This is not an
inexpensive hobby by any stretch of the imagination. To break that down; the
mod kit was $300, two times crane service was 2 X $400 = $800, labor by
Colorado Tower Work was $1600, new rotator was $600, rotator control cable
was $300, a couple of hundred in miscellaneous parts and pieces, if I’d have
had to pay list price for the transmission line it would have run $1500 (it
was obtained in a trade).
I knew going into this project that it was going to run close to 4 grand
but, having a $15,000 installation of a 125’ tower, one antenna on it not
working very well and neither of the beams on the tower Rota table