[TowerTalk] Mosley TA-33 problems.........a bit long

[Butch Butler]

Hi All.....

I was recently given a Mosley TA-33 on the occasion of my tower purchase. I
immediately set forth to disassemble every piece in turn for inspection and
cleaning.

I lovingly put brillo to every piece of aluminum, replaced all the hardware
with stainless steel, double-checked the parts list against what I had on
the floor, disassembled the traps - checking for damage, bug nests, etc.,
bagged everything and set it aside until the 40-Meter Add-On kit arrived
from Mosley.

When the 40M kit arrived a few days later, I assembled everything for the
PHONE section of the band according to the two assembly manuals and
double/triple-checked the measurements.

I nested and tilted the 52ft. Crank-over tower and mounted the antenna on
the mast. I knew that with the tower laid over, any VSWR information I found
would be different once the tower was vertical and cranked to full height -
so, I raised the tower to vertical and broke out the MFJ-259B.

The initial readings (using the frequency settings recommended by Mosley and
with the tower nested) were as follows:

10M...................28.8..............2.2:1
15M...................21.3..............2.1:1
20M...................14.25............2.8:1
40M...................7.175............2.0:1

Lowest VSWR read on each band was as follows:

10M................28.21..............1.6:1
15M................20.815............1.4:1
20M................14.0.................1.5:1
40M................7.22.................1.6:1

The readings seemed to me to indicate a longer antenna than it should be,
so, hoping I could bring the resonant frequencies up the band a little, I
shortened the distance between the two inboard traps (those closest to the
boom) by 1-1/2" on each side and took another reading. Strangely enough, the
resonance went DOWN the band - not UP....confusing!!

I relocated the sections of the radiator to their original position and
step-by-step made each of the possible variations in length for the radiator
- ie., between the two traps on each side of the boom and the length of the
ouboard element sections as measured from the outboard (40M)
traps.........No appreciable change.

I then removed the 40M kit and replaced the original TA-33 element pieces
since I had not checked the antenna prior to installing the
kit............things got worse!!

Lowest VSWR on each band:

10M...........28.136 @ 1.7:1
15M...........20.643 @ 1.4:1
20M...........13.927 @ 1.6:1

As you all probably know, Mosley leaves very little room for
mistakes.........they color-code the traps and all element parts are drilled
to a specific location instead of using hose clamps, so it's really
difficult to put one of these antennas together incorrectly.

The only caveat is this (and I'm not sure if it is a factor): My tower base
is by necessity 12 feet from a 40 x 60 metal quanset building. But the bldg.
Is only 15 ft. high and the antenna is at 53 feet. Can this be an issue?

Thanks for reading my ramblings and I'd appreciate any and all help.

73,
Butch
k4nau