Information Summary

Digital vs Analogue Talkthrough

Unlike conventional repeaters, which use *analogue* talkthrough GB3KD uses *digital* talkthrough. In analogue repeaters, signals are faithfully repeated, warts and all. Because there is a wide variation in people's audio settings, some people would sound quiet and "thin", whilst others would be too loud, thus exceeding the repeater's permitted deviation level, resulting in "clipped" audio.

With digital talkthrough, the incoming signal is digitised, processed, then converted back to analogue. The levels are equalised, tonebursts and DTMF tones are attenuated, and squelch tails are shortened. These and other features reduce listener fatigue, and improve intelligibility under mobile conditions. The downside of digital mode is the slight delay, of the order of 150 milliseconds, between input and output. As you drop carrier, you may hear the last few milliseconds of your "over", and this can lead people to think they were "doubling" with someone. It is perfectly normal, and in some instances it can be a useful indicator of your signal into the repeater.

Latest News - November 2007

The intermittent blank carrier which has been interfering with GB3KD for the past couple of months, was not deliberate. It has been traced to a local amateur, whose rig was emanating an unmodulated carrier near the repeater input frequency whenever he transmitted on 144.725MHz. This was a real signal, not a local mix (a mix would carry modulation). Despite his protestations that the fault lay within GB3KD, and that his expensive rig could not possibly be at fault, changing his rig has effected an instant and complete cure! KRG thanks him for his co-operation in this matter. You can find more on this story in the minutes of the November 2007 KRG meeting.

The "Rogues Gallery" on this website has been partially reinstated, but you will notice that many images are missing, because we can't guarantee that they are copyright-free. Your help is urgently requested - If you have any pictures of yourself or other "gallery" members, and you don't mind them being used on this site, please email them to charlottebronte[at]blueyonder.co.uk (replace [at] with @ of course)

Current status

a) There are still some issues with the DTMF decoder. Some rigs and auto-dialer programs don't leave sufficient gap between identical digits, resulting in "11164" being decoded as "164" for example. Whilst it could be made it more sensitive to gaps, this would cause repeated digits (e.g. a long "1" becomes "11111") due to mobile flutter. If you can specify an inter-digit delay, make it 100 ms.

b) Due to persistent abuse, all connect and disconnect commands now require the user to clearly announce their callsign and the word "connecting" or "disconnecting" prior to, and in the same transmission as, the DTMF sequence.

Hall Of Fame

The following stations have been heard using the repeater by radio:

DX Record Holders