The longest two-way QSO on the relatively new band of 472-479 kHz band has been set by a contact between Australia and Canada. The spectrum was granted as a secondary allocation to the Amateur Service at the World Radiocommunication Conference in 2012.
Experimentation and pushing the boundaries paid off for two Radio Amateurs Steve McDonald, VE7SL, in Canada and Roger Crofts, VK4YB, in Queensland, Australia who made a two-way digital contact in the JT9 mode.
The JT9 contact in the WSPR QSO mode was at 1319z on Thursday September 15, about 30 minutes before Canada’s sunrise with the sky surprisingly bright. Steve, VE7SL, says he and Roger VK4YB worked each other on 630m, the exact frequency being 475.300 kHz.
Steve described the contact in his blog as follows:
Shortly before sunrise yesterday morning, VK4YB (Roger) and I were able to work each other on 630m ... 475.300 kHz to be exact! This is the first-ever QSO between North America and Australia on the relatively new 630m MF band. As well, at 11,802 km, it presently represents the furthest two-way contact on this band, worldwide ... but I don't expect this record will last very long once the US gets the band as I believe Roger's fine station is very capable of reaching much further afield. Our contact on JT9, the WSPR QSO mode, was made at 1319Z, about 30 minutes before my local sunrise with the sky surprisingly bright. Blog readers will know that Roger and I have been carefully watching the pre-dawn Trans-Pacific propagation path for the last week. I have been checking-in with him via the ON4KST LF/MF chat page every morning at around 0345 local time at which point a decision is made ... ‘get out of bed and head for the shack’ or ’go back to sleep’. Each morning's (or in Roger's case, each evening's) propagation quality is assigned a code number by Roger, based upon what he has been hearing during the early evening hours ... a '6' or below is 'sleep-time', a '7' is a 'you decide' while an '8' or above is 'get your butt moving'.”
With his new antenna, transverter and amplifier it seemed that with Roger VK4YB, full advantage of Trans-Pacific propagation could be realized, although the path has not been at its best yet. Ironically the transverters used at both ends were of the VK4YB design, made in Queensland, and will be reviewed by Justin Giles-Clark, VK7TW, in Amateur Radio magazine.
The pair showed persistence by watching the pre-dawn Trans-Pacific propagation. Roger, VK4YB, used an experimental 630m band antenna at his QTH in Moorina, a small rural suburb 39 kilometres north of Brisbane in the Moreton Bay Region. Before the two-way contact he seemed to be the only VK on 630m WSPR mode seen in Canada. The propagation had been doubtful but on the last attempt on the day the historic contact was achieved.
Others had made earlier contacts over shorter distances on the 7-kHz-wide band just below the broadcast AM band, using mainly digital techniques although there have been some SSB, CW and beacon activity occurring.
Writing on his blog Steve, VE7SL, hoped the historic contact will inspire new interest in the band. His advice, particularly to new users, is that it seems that the main mode of two-way communications is CW or JT9, and a simple transverter would allow both modes as well as the use of the WSPR beacon mode.
It is hoped that our contact will inspire new interest among amateurs worldwide and particularly in North America. If you are planning a station, it seems that the main mode of two-way communications will be CW or JT9 ... a simple transverter would allow both modes as well as the use of the WSPR beacon mode. More information may be found here as well as in earlier 630m blogs.”
For more information please see: