Originally Posted by Worldspan
I confess that I'd never heard of 448 as a working frequency. W
448 kHz as a working frequency for ships was only available for use in Region 2 (North and South America) as set out in ITU Radio Regs, not in other Regions - another potential source of conflict at GPO inspections. I suspect that allocation might have been because it had been in common use by US ships when the Radio Regs were amended to define the Maritime Mobile frequency band and its uses. Such anomalies are not uncommon in the Regs when proposed international changes conflicted with existing uses in a major member state and a deal was done to get round the problem.
A similar example was the designation and use in the USA of some of the two-frequency maritime VHF channels. There, only the lower frequency of the pair was made available for marine use, the higher frequency having been allocated to railways prior to ITU setting out the international frequency plan in Appendix 18 to the Radio Regs. This meant that certain of the VHF channels above Channel 16 were not available to most ships in US waters but were commonly used by local ships and coast stations.