HF SSB Marine ITU Channel 601 6200 kHz USB 0300+ UTC 12 April 2017

[R4002]

Tuning around the 3-8 MHz region this evening, right at the bottom of the 6 MHz marine band and I came across a simplex QSO on 6200 kHz USB.  Per the ITU HF SSB maritime frequency channel plan, 6200 kHz is ITU channel 601 and is a "duplex" channel (split-frequency) paired with 6501 kHz.  6200 kHz USB is the ship transmit frequency and 6501 is the coast transmit frequency.  6200/6501 is listed as one of the "USCG Calling" channels which makes sense given the fact that the US Coast Guard uses 6501 kHz USB for marine weather transmissions.  

The users are speaking Spanish and are operating in single-frequency only (nothing heard on 6501 kHz).  Per ITU channel plan, only 6224 kHz, 6227 kHz and 6230 kHz may be used for simplex operation.  

Maybe I've stumbled upon some fishermen actually using real legit MF/HF marine radio with the pre-programmed ITU channels!  [gasp!]

Still going strong at 0332 UTC.