Chris, OE1VMC, is homebrewing a remote antenna tuner. Should be ready in early Spring 2016. Many thanks to Arpad, OE1SZW, for donating the impressive variable inductor (0-60 turns of silver-wire on ceramic cylinder) suitable for QRO operation…. Next step is the implementation of a feedback from the remote antenna tuner to the shack which ensures that the DC motor does not ruin the gears when the end of the coil is reached. I keep you posted.
Antenna tuners are best placed near to the base of antenna towers. As a spin-off of a Master Thesis prepared by our student Zoltan Tornyos the breadboards of Arduino-powered remote control units became available. Zoltan has based his design on the insight that three remote controlled reactive elements (C, L) give the freedom to match more-or-less everything to 50 Ohms. The control unit in the shack (left photograph) commands the tuner near the antenna via Ethernet (right photograph). Stepper motors are foreseen to adjust the reactances, but we still rely on potentiometers for reporting the values to the remote Arduino.
Presently we are upgrading these units to full automation by reading the transmitter frequency from the CI-V bus.
Due to the rapid evolution of the station automation the wiring at the backplanes became a bit chaotic. Yesterday we have started a full disassembly and reintegration of the station and of all its IT infrastructure. Here is where we were starting from:
During the winter term (Oct 2015 – Jan 2016), 12 students took the elective course „Shortwave Radio Communication“ (course no. 389.030). The course consists of two parts: in the first part, the foundations of ionospheric wave propagation are explained, antenna fundamentals (the dipole, the ground plane antenna), and modulation techniques (analog and digital). Demonstations of CW, SSB, BPSK, and JT-modes form the second part. The photos below show OM Arpad, OE1SZW, and OM Chris, OE1VMC, with students while demonstrating two-way communication with East-Malaysia and Australia using JT65-mode on 40m.
Since some time, heavy construction work has been ongoing in the backyard of the Radio Amateur Club. Up to this week, this did not interfere with our QSOs. Now, a large crane is erected very near to our antennas on the roof top, see photo below. Unfortunately, the crane is in the near field of the SteppIR DB36 Yagi on all HF bands. This will distort the pattern significantly.