Of course, not everyone was that keen on repeaters, and the repeater was subjected to various forms of abuse as well as bona fide users.  The worst attack suffered by the repeater occurred when someone forced an opening in the hut where the repeater lives, and put in a smoke device.  Try and justify that to your landlord.... The logic developed in a way designed to withstand a certain level of abuse, and the receiver sensitivity was restricted.  Luckily, over time the conditions changed, repeaters became more accepted, more repeaters came on air and the pressure on the early repeaters was reduced.

In the early 1980s, a new repeater was put under development.  However, there was also a radical shakeup in the group as well, and the repeater was handed over to a new group of people to complete the engineering, shake out the bugs and get it on the air.  This job was completed in late 1984, when the MkII was put on air.  Compared with the MkI unit, MkII was much more sensitive, and the logic was made simpler and more predictable to use.  This was in turn gradually evolved over the years; battery backup was instigated, a backup repeater was engineered (actually based on the MkI unit, but with a lot of the insides replaced), commercial cavities replaced the original homebrew items, and a commercial colinear antenna was put on the tower, which gave markedly improved performance.

However, in the last couple of years, bandplans have called for 2m to be replanned at 12.5kHz channel spacing.   Also, CTCSS has been standardised as an alternative repeater access method.   It would have been possible to re-engineer the MkII unit for 12.5 kHz, but this would not have been the optimum solution.  Both MkI and MkII units were based around the Storno CQF600 series, a 1960's design, which was fine for 25kHz, but didn't perform as well at 12.5kHz (parts of the IF were actually designed for 50kHz spacing).  To get in CTCSS, convert to 12.5kHz and generally produce a better engineered unit, a new repeater was built based around the much later Storno CQF9000 series base station.   See 'specifications' for more information.

This MkIII unit came on air in January 2000.  One or two issues have come to light on site with the new repeater.  The MkIII has a higher power PA, and when combined with a faulty antenna has caused one flashover in the transmit cavity leg (yes and at less than 25W).  Once this was cured, and the antenna replaced, we have still found one faulty cable which caused more desensitisation.....have you ever seen a cable that measured 300mV all on its own between centre and ground?  A few more of these and maybe we could have got rid of the backup battery!