5690KHz Japanese/English voice tx

[Looking-Glass]

At 1244z I happened upon two Japanese men on 5.690MHz USB in broken English and Japanese giving what appears to be a weather report, figures given were in mixed Japanese/English and also heard "QNH" mentioned.

Cannot find any relation to aviation on this frequency, found reference to European marine though in the past on this one.

Maybe this is a Japanese airline LDOC frequency? Then again marine?  However, the term "QNH" is used almost exclusively by the aviation sector and not marine. No Selcal check heard, both stations were in the order of 5X5 to 5X8 reports.

Maybe someone on HFU has reference to this one, especially the HF aviation diehards?

[Exo]

This is an international standard "Aero Off Route" channel.

Generally open Aeronautical freq, but usually not LDOC or RDARA or MWARA.
It can be utilized by all types of aircraft and air-ground or aero comms orderwire (private, corporate, mil) entities.
Most of the "Aero Off Route" channel allocations are well known for mil air.

Other standard "Aero OR" channels may be found at 3.0 kHz intervals up from this channel.
etc.
5680 international AERO SAR channel with Maritime SAR interoperability (+/-4 kHz protection)
5684 "Aero Off Route"
5687 "Aero Off Route"
5690 "Aero Off Route"
5693 "Aero Off Route"
5696 "Aero Off Route"
5699 "Aero Off Route"
5702 "Aero Off Route"
etc.

[Looking-Glass]

Thanks EXO, much appreciated and mystery solved for me...