QRV on ALL BANDS: 1.8 MHz to 430MHz, CW SSB RTTY PSK31 HELL SSTV
Worked the 40 zones on 160m in one season
My other hobbies: Motorcyle (BMW K 1200 RS + K 1600 GT Sport), Parachuting, Karate (Black Belt, 2nd Dan)
Cox, my faithful four-legged friend
The antenna tuning unit used with this 27m Titanex vertical was originally designed to operate on 40, 80 and 160m (left photo). With an existing 40m Yagi in place, it seemed advantageous to remove the 40m setting, then to replace by another 80m setting. Therefore it was decided to re-design the original ATU by using more performing components (low-loss inductor, better variable capacitors, vacuum relays). Contact was made with F6ARC who modified the same box at FM5CD’s QTH in 2011. He also suggested to add another frequency setting on 160m. F5OJG and I purchased news materials as required. After all the wiring was completed (right photo), adjustments were carried out at the bottom of the vertical in the presence of the interested persons! After a few tries (with an outside temperature of 3°C), we obtained a perfect 1:1 SWR on 1.820, 1.840, 3.520 and 3.790 MHz.
The coil inductance can also be slightly changed, using a remote control system. Under these conditions, optimizing for minimum SWR becomes really easy. This makes more efficient use of the bandwidth on either 80 or 160m.
Motorized tuning elements are located on the right side of the box (12 vdc window lift motor with limit switches).
One air relay is used to switch between 80 and 160m. Four vacuum relays are used to select the 4 different 80/160m settings. Resonance is obtained at 3.790 MHz using one capacitor, resonance at 3.520 MHz by connecting another capacitor in parallel.
Photos below when I was in the army (1st RHP) in Tarbes... (9 months in Djibouti)
Thank you for visiting my page, see you on the air!
Regards from "Dom", F5OHS
6161501 Last modified: 2015-07-16 00:20:11, 9597 bytes
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