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G3NJA - G8NJA - GB3TR
A POTTED HISTORY
From its beginnings in the late 1970's this repeater has been through quite a few changes. These changes were not only through the people involved in constructing the RF and Mechanical side of things, there is a very long list of those, but also the various sites, antennae and actual RF equipment itself.
When GB3TR first went on the air from the garage in the garden of a bungalow belonging to Steve 64EDG on the 29th March 1980 it was almost a wonder to behold, for those there at the time. None had ever worked upon a repeater before and the whole thing had to been put together in an almost true "Amateur" way.
The transceiver was a UEL Lion, this was a commercial repeater unit donated by Bob G3PQH, consisting of two mobile units in a case and a very nice ten ampere power supply. This was connected to a logic unit using a Sinclair Mk 14 computer with a program developed by Martin G8HHQ and G8SXC at University. The six cavities had been constructed by Les G3GAO, from plans received from the operators of GB3SN, and he had made them very solidly, so much so that when they were placed into a wooden casing and packed around with polystyrene insulation it took two people to carry them, but they have proved themselves over the years and although they are now in two separate boxes they are still very stable and represent a vital part of the repeater.
The antennae for the repeater was a Ringo Ranger for receive, mounted on a twenty foot pole, and just above the roof of the garage was a home-brew Slim Jim in a plastic tube for transmit. With this setup it was possible to work repeater around the Newton Abbot area and almost into Torquay when mobile. Fixed stations from Plymouth & Exeter could also get into it but by today’s standards it was very limited, to say the least.
Within a short time the receiver gave trouble and an Icom IC22a donated by Bill G8XST was modified by Colin G4FCN and pressed into service. This improved things greatly but it was still proving to be a "local" repeater
One day we were told that the bungalow was going to be up for sale and Steve was moving away, which prompted a hunt for a new site for the repeater.
Shut down because of the site change, the repeater was off the air from 19th September 1981 until 30th September 1982 when it reappeared from its second home on the farm belonging to Andy G3TLK on the outskirts of Torquay. Now rebuilt, using the IC22a both for receive and transmit (with an outboard PA), complete with a new logic system (GB3US Mkl) and the original cavities and PSU from the UEL.
A fifty foot mast was constructed for the repeater by Andy and with a twenty foot pole inserted into the top it was most impressive running a pair of half wave end-fed dipoles spaced twenty feet apart. As the years passed the dipoles were changed for a single Jaybeam C5 collinear on the top and a simple dipole for transmit mounted below it. Due to problems with the wall of the barn and almost constant gale force winds the height of the mast was reduced and thoughts turned to planting a mast away from the barn altogether. Using part of another mast that Andy had constructed for himself some time earlier, he had used his tractor to dig the hole in a suitable spot. On the appointed evening a team of TARS workers got together and placed the mast into position where it was held firm by an array of guy ropes.
It was agreed that at six-o-clock the next evening work would start in earnest.
The next day, six pm duly arrived and a large team got to work and were finished at eleven pm that night. >
It had been a clear bright evening and was still light enough to work at eleven. By the time sixteen plus tons of concrete had been mixed and poured into place around the mast, it was a very tired and dusty crew that went home that night.
With the new feeder and running just the C5 collinear from the top of the new mast GB3TR was back in business within a week and the old mast was removed from the wall of the barn.
With Mike G1FON doing the pushing to improve the coverage of the repeater it was agreed that the repeater was soon going to require a change of site, but, to where, was the question. The logical suggestion was Beacon Hill, being the highest spot around the area. It was known from other sources that the site was supposedly available but that to put anything up the mast meant the services of a professional rigger, something that does not come cheaply.
After being used to tinkering with our own aerials we held back. Mike located the man that owned the site at Great Hill and approached him about it. Tests from the site had been very encouraging but it was a big step to take, committing the club to operate the repeater from a commercial site with its associated costs and problems.
While site hunting was taking place a link had been forged with the operators of GB3WD which was to allow us to replace some of the equipment used for the repeater
. When the site change came about only the cavities had to be moved. The rest of the repeater now consisted of a Pye T100/R18 combination and a new logic board mounted into a splendid rack cabinet making it look very professional, It looked so good that it made the other commercial installations look a little shabby.
Commissioned and back on the air after being switched off at 09:00 hrs on Saturday 30th July 1988 and back on again at 13:00 hrs the same day, the repeater was now operating from its new site, all that was now needed was to fine tune the antenna’s, now being a pair of folded dipoles. Having got them into what appeared to be the best place according to the map Mike tightened up the clamps and climbed down to hear the different stations that were now using the repeater and already giving an indication of the change in coverage from the previous mast just some sixty metres below us down the hill.
Subsequently the logic has been changed from the GB3US MK1 to the MK2, this being brought about by requests from users saying they did not like the constant "blipping" up of the repeater by unknown operators - who were too tired to give their Call Signs if indeed they had one!!. As a majority appeared to be against the interference the second board was obtained and populated by Bill G8XST in his spare time (pause for a short laugh). When it was first tried out it caused chaos as the audio levels between different parts of the equipment were found to vary. With this problem sorted out the board was reintroduced and the fun began.
Since the introduction of the MK 2 logic, most users have mastered the technique of a shorter burst of tone and five seconds of audio. It would appear some rigs, notably the Kenwood TR751 have been found to be unable to access the repeater. We believe this is due to the audio tone burst being too long in duration.
Some work has been done by Bill G8XST behind the scene which means that even the Icom rigs with their peculiar double squeeze of the PTT to obtain the tone can now be accommodated and open the repeater.
Being based upon an Eprom the new logic is very flexible and with the programming assistance of one or two members, Bill has managed to start fine tuning the way the repeater operates, particularly in respect of the speed and number of "PIPS". I hope you will bear with him during this time until he has it at a state where the repeater "sounds" correct. Feedback from all users would be appreciated.
Since being in its new location GB3TR has represented the club well. It is the only repeater we know of in the UK that is sponsored by a Club as distinct from a Repeater Group. This does not mean that the club funds the repeater. In the beginning TARS did help it get off the ground, but by ploughing all monies back into the repeater to pay for its general upkeep, we use the little left over to pay off some of the outstanding debt, so those who do not use the repeater need not fear that their Club Subscriptions is being used to pay for something they might consider a luxury they do not themselves use.
In line with all modern trends the running costs of GB3TR get higher every year and work out at something approaching one pound and fifty pence a per day. This is a figure that we only just cover during the year and we pray for no breakdowns within the equipment. A valve would set us back over thirty pounds, and if the antennae were damaged in more gales similar to those splendidly described by Mike in the TARS Talk Magazine it could cost up to nearly a hundred pounds for each one to be replaced. We have to remember now that the site is very exposed and very seldom is such a thing as a calm day known on top of the hill, meaning anything that is put outside in the weather has to be made to commercial specifications and consequently commercial prices.
Thanks to all Radio Amateurs that have given freely of their time and money in helping to construct and maintain GB3TR from its conception back in 1977/8 to today. The list is long and I think that if they read this little piece of history they would not be offended in not seeing their Names/Callsigns in print.
If you have read this little story with interest and feel you would like to subscribe in some way to keeping GB3TR operational, your donation will be more than welcome.
Send your donation with your details to the TARS Treasurer
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