Also this month a station on the tropical bands was chosen. This is mainly because this particular station is one of the few station still transmitting from Central America on tropical bands and it is a very friendly one for radio ethusiasts. I remember to have heard back in the 20´th century and got also a reply then. I tried it a couple of times this fall when it was transmitting with a temporary small transmitter on 4055 kHz but I think it was rather hard to capture in Europe. Now after the end of October ( I checked it on Oct. 28th and found it with rather good signal) it was again on 4052.5 (4052.455) and since then it seems to be a regular visitor on this a bit odd frequency between 75 and 60 mb.
Information I have seen (thanks to R. Wayne Borthwick, VA7GF vie Glenn Hauser DXLD):
The antenna is a 89 m long with a phasing stub 11m long hanging near the middle. The two current nodes are separated to give near maximum collinear gain (about 7.5 db above isotropic theoretical). Since the antenna is oriented NE to SW it is ideally oriented toward covering Mexico and Western N. America on one side and C. America, S. America on the other side.
I designed it so the lower elevation angle minor lobes are about 8 to 10 dB down off the ends of the antenna to cover E. USA and Europe. It hangs over a gully with a max depth of about 25m and is end fed through a matching network by approx. 10 m of RG8 coax. The matching network is mounted in a sheet metal box on the tower and consists of a single 30 cm diameter coil of three-eighths soft copper tubing. Top of the coil is to antenna and bottom to ground with the 50 ohm tap about 1.8 turns up from the ground.
The big problems in the installation were getting a good solid ground in dry earth covered by concrete and buildings. Lots of work by the mason chipping holes for the ground wires in the concrete. It also turned out the power feed from the transformer at the edge of the of property had a bad neutral so today that got fixed. Prior to that we were completing the neutral current through our antenna ground, and indication that the antenna ground is at least capable of a few amps at 60 Hz without too much voltage drop.
Hope this and the 500 W carrier from the Omnitronix solid state transmitter helps reception up your way. 73 (R. Wayne Borthwick, VA7GF, Oct 29, WORLD OF RADIO 1537, DX LISTENING DIGEST).
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