Telford rally exhibition station G2BBC/P.
The Telford club decided to have an LF demonstration at their rally which was held at the Aeronautical museum at RAF Cosford this year. Martin G3UKV called me and asked whether I could put on a portable station for the event (136kHz talk-in station....). I enlisted the help of John G4GVC as I didn't want to be tied to the rig all day. I arrived on site at half past seven on the day of the rally with a car full of the usual old rubbish that I take when I go to Scotland.
The day was warm and sunny. The stand was to be set up at the end of "hangar 1" which was a large metal hall full of aeroplanes. Phil G0VSJ reckoned that we could feed the aerial wire out between two of the sliding metal doors which had bristles to seal them against draughts. I surveyed the general area and decided that I could sling a long wire between the girder framework for the sliding doors at the end of our hangar and the same point on the next hangar, about 100mtrs away. These frameworks were about 16mtrs high.
This is hangar one. We were just inside the open door, the antenna was strung from the framework on the left.
Using as roll of sticky tape as a projectile I (eventually) threw the plastic string over the frame of hangar 1 and attached the wire. No insulator, I was banking on it not raining! The same was done at the other hangar and the string disentangled from the barbed wire fence running beneath the aerial. When it came to pull up the wire I noticed that the tail of one of the aircraft standing between the hangars, was in the way. I had to throw the wire over the wing and was glad nobody was about when I bounced my roll of tape loudly over it! I pulled the aerial up as much as I dared, still a bit saggy but good enough to clear all obstacles and returned to sort out the feed through the doors. Phil climbed up inside the hangar and pushed a wire through the bristles, I attached the end of the aerial and we pulled it through.
Here is a "digitally enhanced" view of the antenna as it passes over the tail of an aircraft to the distant hangar. Taken from point A.
Again from point A, here is the wire dropping down and through into the hangar. You can see one of my bits of insulation at the point that it goes through.
Getting it over to the stand was a bit tricky as we didn't want anyone to touch the wire as we were transmitting! I threw some more string over an aircraft wing in the hall and hoisted the wire up about 3mtrs in the air. A fishing rod taped to the table leg at the station end was the final support. Lastly I ran an earth wire over to the nearest metal door and fixed it under a screw head, then I taped it to the floor.
Having set up the transmitter (YXM 1kw) and receiver (TS850) on the table I listened on the band and it didn't sound too bad, nice loud DCF39 and not much noise. I tuned up and was surprised to get 1A antenna current at the lowest power setting, about 100W. I increased the power and the current suddenly dropped and the SWR went up. Switching back to receive, no signals. I went outside to see what had happened. The wire had arced over to the metalwork where it passed through the doors. I moved it away and managed to wedge a bit of expanded polystyrene between the wire and the door. Signals restored, I decided to try a call at the 1 Amp level and worked GW4ALG and G3OLB followed by EI0CF, all with reasonable reports. John arrived at about 10 o-clock and took over the operating whilst I went for a well earned drink!
Here is the station in action. You can just see John behind the TS850 with the TX and ATU to the left. Visitors stare in wonder....
During the day we had 14 contacts and worked 5 countries; G, GW, EI, PA, and ON. By the afternoon I had improved the insulation of the wire through the doors by pushing bits of plastic through the gaps.. We were able to push the current up to 4 Amps which is the condition we were using when we worked Rik, ON7YD.
Over all it was a very successful day with a lot of interest shown in the station. If we only persuaded one person to get on LF then it would have been worth it and there were at least 10 who SAID they would come on!
We must do some more... John!..... Where are you going?.... Come back!