The Maritime Radio Historical Society (MRHS) will join others around the world in marking the 100th anniversary of the International Radiotelegraph Conference. Delegates to the 1906 gathering in Berlin designated 500 kHz (600 meters) as the international distress and calling frequency and SOS as the distress signal, and they signed the International Radiotelegraph Convention, which eventually became the International Telecommunication Union Radio Regulations. MRHS’s KPH, which began operation in 1905, will activate at 0001 UTC on Saturday, November 4, on 500 kHz and on its working frequency, 426 kHz. “KPH will send special messages and marine information using 500 kc as frequently as possible, keeping in mind that other stations share this frequency,” says the KPH Chief Operator Richard “R.D.” Dillman, W6AWO. “Longer bulletins will be sent on 426 kc after an announcement on 500 kc.” Dillman says KPH will monitor 500 kHz at all times for calls from ships and will observe the silent period. KPH ops also will listen between 505 and 510 kHz for stations operating as part of the ARRL WD2XSH experimental group, although Dillman adds that contacts between those stations and KPH will not be possible. MRHS Amateur Radio station K6KPH will monitor 3550, 7050 and 14,050 kHz for calls from radio amateurs wishing to submit signal reports. To obtain a printed confirmation of KPH reception, send reports to D.A. Stoops, PO Box 381, Bolinas CA 94924-0381 USA.