There are currently three D-Star digital repeater systems in the Central Scotland Area. One is to be located in Glasgow (GB7DG), One in Ayrshire (GB7DW) and one in Fife (GB7DE). These systems are independently financed and operated and are being co-ordinated by John Dundas, GM0OPS. (i.e. They are not CSFMG repeaters).
D-STAR (Digital Smart Technologies for Amateur Radio) is a digital voice and data protocol specification developed for use in amateur radio. D-Star compatible radios are available on VHF and UHF amateur radio bands (2m, 70cm and 23cm). In addition to the over-the-air protocol, D-Star also provides specifications for network connectivity, enabling D-Star radios to be connected to the Internet or other networks. D-STAR is the result of research by the Japan Amateur Radio League (JARL) to investigate digital technologies for amateur radio. To date, other than ICOM - no other amateur radio equipment manufacturer has chosen to include D-Star technology in their products (Note - The Kenwood unit available in Japan is a rebadged ICOM).
It should be noted that the voice compression used in D-Star is somewhat similar in its operation to the voice compression used in digital cell phones, satellite telephones, and VOIP telephone circuits. Because of the heavy amount of compression, the subtle qualities of the voice are noticeably altered - particularly in the presence of strong background noise.
For an audio clip providing a comparison of normal analog and D-Star, click here. This audio clip (260kB) provides a demonstration of how "pretty good" signals sound using analog and D-Star. Evident in this recording are the effects of the audio compression on the voice quality.
Additionally, as signals degrade due to fading and/or interference, one doesn't necessarily hear noise, but rather odd-sounding artifacts - or perhaps nothing at all when the decoder is suddenly unable to make sense out of what it is receiving.
For an audio clip demonstrating what happens when both analog and D-Star signals are degraded due to multipath and weak signals, click here. This audio clip (260kB) provides a comparison of how analog and D-Star signals behave when conditions worsen. Both signals were generated "live" and consecutively using the same transmitting and receiving gear (Both Audio files Recorded in the US).
GB7DG - Glasgow Area (Newton Mearns) - 2M (RV62 - 145.7750/-600), 70cm (439.7/430.7), 23cm (TBA)
GB7DE - Edinburgh /Fife Area (Largo) - 2M (RV51 - 145.6375/-600), 70cm (439.6/430.6)
GB7DW - Ayrshire - 2M (RV49 - 145.6125/-600)
GB7GD - Aberdeen - 2M - 145.6875/-600
GB7DK - Stranraer - 2M - 145.6875/-600
D-Star Simplex Activity can be found on 144.6125 and 438.100 MHz
For more information contact GM0OPS or visit www.dstarinfo.org