ARRL AT Tandem W6TDM
Tandem Radio Amateurs Club (TRAC)



Operation BIG GUN

Operation "Big Gun" gets its name from the so-called "Big Gun" radio stations with booming signals and an ability to break pileups to get those rare DX contacts. Although our station was reasonably good, with our TS-430, the linear amp, and the big tribander, our operators didn't seem to have that oomph we thought should be present. So, to improve our "presence", we added 20 more feet to the tower height. Tests will show whether we now can be considered a "Big Gun"!

Surveying Cpto from the Top Though we don't have photos showing our removal of the big HF beam antenna and our old 20-foot tower, we can report that the antenna was successfully removed without damage. The top section of the old tower didn't come down so gracefully, though -- hitting with a thud! All in all, a successful operation.
Then the new tower sections (provided by Bob KM6ID) were lifted into place. Shown here is Paul (KM6LH) working on the re-installed rotator, with the gin pole clamped to the tower's top and its ropes trailing down. He reports that this view from about 65 feet above Cupertino was FABulous!


Reassembling the Beam Paul (KM6LH), Mel (KF6OZ), and John (AC6KA) working on the Beam Antenna, on the roof of Building 200. Our shack is on the top floor of this building, and our "antenna farm" resides on the roof. It includes 6M and 2M beams, the HF beam (20, 17, 15, 12, and 10M bands), a 40-meter dipole, and a number of VHF and UHF verticals.

Checking it out After cleaning up the junctions and playing with the balun, we used the gin pole to lift the forward end of the beam to a 60 degree angle while checking the band resonances, prior to lifting the antenna back into position. You can see Mel near the edge of the roof working with the MFJ-249 analyzer to check SWR on each of the bands, using a temporary coax to the antenna feedpoint, while John (and others) tether the antenna in a more-or-less stable position. We think that's Mark (KE6QCT) whose shadow appears to the left holding another tether line.

Ready to Climb Club president Paul (KM6LH) prepares for another climb up the new 40-foot tower as the rotator is re-installed and wired and control lines are brought into place and tie-wrapped to the tower.

All OK at the Top Paul giving the "thumbs up" sign as he completes wiring the 8-conductor cable to the rotator (for the second time!) He's strapped to the tower by a safety belt, and we followed the safety guidelines we'd set up: belts used by tower climbers; always one or more safety spotters; no one under the tower while work went on above; lots of communication; and a slow-and-easy approach to avoid mistakes.

Feeding the Cables John (AC6KA) works at the rooftop panel where the contol cables and coaxes are fed down to the shack. He acquired 150 feet of new 18AWG rotator cable, clearly sufficient to the task, we thought -- except that it was about 30 feet too short! A quick splicing job to a section of the old control cable gave us enough length to reach the shack once again. Later, the new 200-foot RG-8 coax cable (THIS time we got it long enough!) was snaked up (or down) through these conduits from the shack to the top of the tower. Jay (AC6OW) did the dirty work of soldering the connectors to each end of the new coax run.
John served as organizer and crew leader for the "Operation Big Gun" project for TRAC.

Wiring the Rotator Meanwhile, back inside the Shack, John checks the color codes and screws down the wires in the control cable. Minutes later, we fired up the rotator (and found that the brake release worked, but there was no rotation). Re-checking the manuals, we found that we'd mis-wired the connections at the rotator itself. One more trip up the tower to correct this, and we found that everything was now working properly.

Next steps: install the 40-meter rotatable dipole above the tribander; and replace old 40-meter wire dipole with an 80-meter one, or maybe a G5RV.


TRAC || Paul KM6LH || email to Mailto: wesling_paul || January 22, 1996