My interest in ATV began in 1998 when Con EI 7 DJB demonstrated ATV to the Cork Radio Club. I was fascinated at how simple the process was and asked Con to let me have a "hands on" of the equipment. Con had, for years before, been demonstrating this stuff but I, being blind, took no interest. However, this time I was hooked. I got the necessary kit from the Worthing ATV Group and along with EI 1 CS (who I coaxed into joining me in this project) began our career in ATV. My first experiments, after getting Tim Watkins, a good friend, to put together the Worthing kit, were in sending pictures around my home. Soon after, I got a few antennas from the Severnside ATV Group and tried to send signals from my house to another ham friend, EI 7 HN, Vincent, who lived about a mile away. I now know at first hand the thrill Marconi felt when he sent his brother over the brow of a hill, with a shotgun, to signal if he could receive his signals from a spark transmitter. After days of trying I will never forget Vincent's excited tones as he shouted through our 70cms repeater that he had a picture from me!

Subsequently I succeeded in establishing contact with my old buddy EI 1 CS about 2 miles from me and together we soon agreed that a repeater was needed to get signals on 23cms any further in hilly Cork. I immediately began to experiment with my Worthing rig and a satellite receiver on a frequency split of about 40Mhz. This was all on the 23cms band. Again, a bit like Marconi, I was luckily using and old Uniden Sat rx and as it was half deaf, to my absolute surprise, the setup worked as a duplex transponder without any filters! Finbarr, EI 1 CS worked successfully through it from his home, while it was on my bench.

I negotiated with the local RTE people to let me use Spur Hill as a transmitting site and started the project on a talk-through basis. It worked fine, and we had a lot of fun. Needless to say we got ambitious and we soon added a beacon, courtesy of Con EI 7 DJB, who donated his Amiga Computer complete with a program called SCALA running pictures and sound. Now we had to approach the problem of how to switch from the beacon to the incoming signals! The boys in Worthing kindly emailed me the details of how to construct a sync pulse detector. Fred EI 2 EG, sadly now deceased, kindly constructed this for me and insisted on etching his own board instead of using veroboard. Now we had a fully working repeater.

At this stage we were about 18 months from the start of the project. A subsequent donation of a 4 screen splitter and a fully working second hand camcorder meant that we could have choices of screen material and this was achieved by Tim Watkins building into the 4 screen split box a full DTMF tone control system. The repeater, at this stage, was using two Alford slots, one on the TX and the other about 12ft. away on RX. Fred EI 2 EG, made up the innards of these for me, again based on information from the Worthing Group. I did the final assembly myself and to my amazement they worked. We were getting signal reports from up to 15 kilometres away and we were using only 1 watt on transmit. Tuning these slots was difficult. It involved milling a slot in the outer of the coax on each side of the coax at the feed point on the inside of the copper pipe. In the design the length of these cuts were specified but getting the SWR correct was hit and miss. So I eventually got the idea of using silver paper wrapped around the internal semi-rigid coax and sliding this up and down while listening to my talking power meter, to get the correct distance of slot that were milled into the outer of the semi-rigid as matching. I was just able to get the tip of my little finger through the main slot in the copper pipe and push the silver paper up and down. Once I got a good SWR with a test signal from the G1MFG unit on the bench I carefully dismantled the innards of the antenna and wrapped insulating tape around the silver paper. It is still there!

I also found that a quad antenna for 1.3Ghz could be easily made from a length of ordinary TV coax by baring about 11 inches of the inner leaving the plastic on it. Bend this one inch to the right, then two inches up, bend it again and so on so that you have a quad with about 2 inch sides. Back at the coax, just wrap the surplus around the braid to get any coupling and you have a quad antenna that is not DC shorting to a Sat RX, and it should have about 3db gain! Subsequently I changed the gear to GIMFG and a linear giving 15 watts out. I did this change, as I was impressed with the size of the modules and the PLL frequency control. I also liked the two sound sub carriers as this would help to keep those using old satellite RX units on side. I also bought a full duplex filter from ID-Electroniks in Germany and succeeded in getting the whole lot to work on one Alford slot antenna without any discernable de sensing. Giles Reed, G1MFG, told me that no ATV repeater in the U. K. was using only one antenna, particularly when they were running 15 watts. This is the current state of our repeater EI 2 TVR.

Getting this licence in itself too has a story. In complete ignorance of the antagonistic attitude of ComReg to ATV, I wrote to them explaining my project. Within a week I had my licence for the transponder, EI 2 TVR, the first licensed amateur transponder in Ireland. Subsequently, all the other ATV groups, both in Dublin and around, asked for a copy of my letter of application to see how the hell I had done it! Needless to say I obliged.

I wish to thank all those who helped in any way with this project either by putting together kits or driving me up and down over and over again to Spur Hill. Of course, we are indebted to RTE whose head Engineer in this area, John Hearne, EI 2 FG, actively encouraged me to use the Spur Hill site as it was the site of the first commercial TV transponder for RTE under the then Engineer, Bob Law, also a ham, EI 9 E. He now also has the first ever licensed amateur ATV transponder in EI on site.

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