How many simultaneous QSO's can the repeater support?
One. Like any other repeater, GB3KD only has one transmitter and one receiver. What it hears on radio it rebroadcasts on radio and the Internet. And what it hears on the Internet, it broadcasts on radio. Although up to 10 stations may be simultaneously connected via the Internet, only one person may speak at once, and everyone else listens.
Why is there a delay through the repeater?
Unlike other repeaters, GB3KD uses digital talkthrough. The incoming audio is sampled, and converted to numbers - 8000 of them per second. The numbers are manipulated to perform de-emphasis, filtering, gain adjustment, tone detection etc. They are then digitally mixed with Internet audio and local tones, announcements etc., then converted back to an audio signal. One reason for the delay is that the numbers are "collected" from the sound interface in blocks, because it's a lot more efficient than collecting them in real time. Another reason is that some of the processing functions need to operate on blocks of numbers, rather than in real time. The processed audio is also "delivered" to the sound interface in blocks. Thus, for a given audio sample, a finite time could elapse before that block is collected. After processing, a further interval elapses before the sample re-emerges, hence the overall delay.
When I drop carrier, I hear a snippet of voice - was I doubling?
Probably not. It is most likely the last 1/4 sec of your over, delayed through the repeater (see above).
Why is the coverage so limited?
Turning the usual repeater idea on its head, GB3KD is located in a valley, rather than on top of a hill, and only runs 2 watts into the aerial. It is intended as a "community" repeater, rather than for wide-area coverage.
Can I ragchew on GB3KD?
Yes, providing you keep individual overs to less than 3 minutes, and allow plenty of opportunity for others to use the repeater.
I don't have CTCSS, can I still use GB3KD?
Yes. The repeater will "open" using a 1750Hz toneburst, or even a whistle. Once it's open, carrier alone is all that's required.
I'm told that repeaters are meant for mobiles. As a fixed station, am I allowed to use it?
Everyone is welcome on GB3KD, regardless of station type. Gone are the days when there were lots of mobile operators, so it makes no sense to restrict usage. All we ask is that you give priority to mobiles, because they may only be within range for a short time.
We can hear each other on the input. Should we vacate the repeater?
Unless someone else wants to use the repeater, you might as well stay put. Repeaters act as focal points for activity, and activity breeds activity! These days we need to keep people talking, or we'll lose our repeaters, and eventually our amateur bands. Also don't forget that there may be people listening on scanners, handhelds, mobile stations, and the Internet who may not be able to hear (or join) you if you QSY to simplex.
I can hear GB3KD perfectly. Why doesn't it hear me so well?
Unlike your station, there is a lot of filtering between GB3KD's aerial and its receiver, and this imposes significant losses, making the repeater seem "deaf". It is our intention to upgrade this filtering to reduce the losses, but good quality filters are very expensive and rare, so your patience is appreciated.
Some DTMF commands work, but others dont?
According to the terms of your licence, you're supposed to announce your callsign whenever you make a transmission, and this includes keying in DTMF commands. That aside, it is also bad manners to connect and disconnect the repeater without announcing yourself and your intentions. In the past we've been plagued by people abusing the DTMF commands without identifying themselves, so we have been forced to make identification compulsory for certain commands. If you want to connect 'KD to another station, you must announce your callsign, followed by the word "connecting", followed by the DTMF command. e.g. "G8PZT connecting to GB3IE (dtmf here)". A similar proceedure is used for disconnecting