Specifically they are using a mix of ~70 calls from Y81A through Y89U. Prefixes seen on the live webcast (slideshow) were: Y81 Y82 Y83 Y84 Y86 Y87 Y89 (no Y85 or Y88) They rejected some callsign combo's due to length or too many dits.(etc.) Mike VE9AA Mike, Coreen & Corey Keswick Ridge, NB