What better place to start on the subject of Amateur Radio History in the South East than with the BBC’s television transmitter mast at Crystal Palace which has always laid claim to being among the most adventurous and successful of post war engineering feats. At 710 feet high and standing on the site of the sadly fated Crystal Palace, the mast can been seen for many miles in every direction.
The mast once hosted the Amateur Radio Repeater GB3LO, which later became GB3SL. With the transmitting aerial located on the second leg up, as high from the ground as Nelson on his Column, it had a great coverage. Sadly, I feel, we lost a big chunk of the south east’s radio history when GB3SL ceased transmitting and closed down completely many years ago. Its passing left a huge hole in the 2mtr repeater coverage across Kent and the south east. We heard a few rumors and various people talked about coming up with a replacement, but nothing ever seemed to mature from those rumors. It must have been around September 2003 when the nucleus of the idea for a replacement repeater first sparked into the mind of Tony Ravelini, G1HIG and he set about conducting a feasibility study, which led to a few months of of intense research. This in turn led to the formation of the Bromley Repeater Group.
The first step was to find the equipment. Tony was fortunate enough to locate and purchase two Philips FX-5000 base station repeaters, four cavity filters, two battery backup supplies and the power supply unit. The two FX-5000 repeaters were 24 volt, 19 inch rack mounted units, with 100% duty cycle and were originally configured to operate around 148MHz. All of this equipment was of the highest commercial quality and in mint condition. However, this stack of equipment became another piece of furniture in his hallway whilst he searched for a location for the new repeater. He had already tested the water at a number of locations in his search for a site, including his own home.
Finally, he managed to secure a site which is itself steeped in amateur radio history. Located at Well Hill, Chelsfield in Kent, it was the site that once hosted GB3NK on 433.100MHz until its re-location to Wrotham in 1976, and more recently, GB3NWK which operated two microwave beacons on 1296.81MHz and 2320.85MHz. At 600 feet ASL this has to be considered a prime site. However, before any of this had even taken place the search for a callsign had been underway so that the application for a licence could get started. GB3OK, standing for Orpington, Kent, was the brainchild of Jeanette, G1UPT. It turned out to be a fortunate suggestion and one that attracted a catchphrase when Arthur, G0MLV was heard to say “is everything GB-OK” over the radio. The phrase caught on and before long many people began to ask if everything is “GB-OK” with the new repeater.
GB3OK proved to be both popular and a little bit of a problem. The early tests of the repeater revealed an enormous coverage footprint, much larger than had been expected and this produced a few ‘teething troubles’ for the repeater group. Tony began getting reports of co-channel interference from other repeaters which were using the same frequencies and ctcss tones, even from as far away as Birmingham, a distance of more than 100 miles away ! The repeater’s coverage footprint was ‘trimmed down’ and reduced in order to address these issues and finally things settled down. GB3OK’s coverage was still quite extensive however, even on reduced power giving excellent coverage inside the M25 area and extending to areas outside the orbital motorway particularly into Kent and the South East.
