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Naval Academy Amateur Radio Club
starts repair of 3 "mini" Bertha towers
Phase 1:
The first of three Bertha's gets inspected. It was a fair but cloudy Sunday, April 2nd, 2000. You are looking north along the Sailing Basin. Tower 1 is in the far background with a 40 meter beam (sans reflector thanks to Hurricane Emily). Tower 2 is in the near background, with a 20meter over a 15 meter. We are on Tower 3 with a 10-15-20 tribander over a 10 meter.
Midshipman Second Class (a college junior) Russ Meier KB3EKM documents the wiring on the terminal board. Rust is evident on the poles,
having not been painted in 10+ years.
Mike Waranis, KF4PVN, MM1, USN holds the ladder as we will see what this one holds.
Birds had gotten into this control box, and built a nest...
The nesting materials and trapped water have badly corroded the internal machinery.
This wiring is barely intact.
It will be hard getting these bolts off, but this shows the size of the gears.
The main gear around the upper tower is bolted from two semi-circles.
Upon closer inspection, this pinion might be cleaned up, but what about the internals of the gearbox?
You can see the azimuth decoder under the motor (upright cylinder), but the 360-degree limit
switch completely desintegrated.
Since this one had little promise for disassembly at this time, we left it on the tower.
One more shot before we button it up again.
This 20meter and 15meter beam will have to wait a bit longer to be able to point east.
On tower number 3, the insides were in VERY good condition, only
light surface rust.
The wiring is in great shape, not even brittle.
We jotted these color codes down before disassembly, but it's good to have a visual record, too.
Ahhh, an intact limit switch!
We got carried away, in rigging down the good box, and didn't get any pictures. We did have to hacksaw
the supposedly detachable link, but we can get or cannibalize one, and the chain is in good shape, soaking.
We will disconnect the motor from the gearbox and verify that both turn freely by hand, then check the motor
windings. The tower also turned by hand, but will need some greasing (if we can figure where the grease fittings are.)
We DESPERATELY need a Telrex rotator controller and indicator, as ours disappeared many years ago.
Please contact the club via our QRZ callbook entry if you can help us out!
Phase 2 will be posted shortly!
Point of Contact :
LT Skip Johnson/K3FOR/NNN0PEK, Club Advisor
Revision Date :
URL : http://www.qsl.net/w3ado/
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