= Radiotelegraphy in Meteorology =


  Meteo Service was historicallly very intence user of Radiotelegraphy. Meteo services existed
practically in every country on the world and was crucial for maritime, aero, military and many
other users. Radionavigational aids were very rare at the time and aircarfts and ships safety
depended on meteorological broadcasts much more than today.

  If we look into old callbooks or frequency lists we can see a lot of
small stations classified as Fixed Service. These small stations established
in remote areas or islands were greatly communication facilities for meteo service
plus sometimes other activities added as a part of meteo observations gathering
network to produce full picture of weather conditions.

  A lot of aero, coast or naval stations transmitted meteo broadcasts and additionally also
specialized meteo stations existed, sufixed with METEO word after their name (localisation).
It could be also specialized radiocommunication stations for meteorological service or just
function covered. Latter was typical when small commercial telecommunication station won
contract for transmitting meteo broadcasts.

  During 2WW meteo service was "militarised" and worked in enciphered version from many
field aerodromes since it was crucial for air force operations. Great cryptological war was waged by
all sides of conflict to break enemy's military meteo codes.


  Meteo Codes like all telegraphic codes were "zip programs" of "Victorian Internet".
Instead of sending long sequencies in plain language it could be send in condensed form in
few digits only. Initialy many various meteo codes existed (see [5]), many on national or organisational
basis, but by years standarisation tendencies clearly can be seen. WMO implemented well-know
international meteo FM codes [2].


  Voluntary Observations Service was maritime meteo observations program. Selected ships
both merchant and naval transmitted radiotelegrams prefixed OBS, in 5F form, encoded by
FM-23 code. This feature is simulated in RARS on maritime bands. FM-23 code is generated
partly dynamically, so you will hear present date, time , etc. There is over 1800 vessels
in the 'Air', mostly listed by WMO publications [1].


  Unfortunately not many meteo broadcasts are currently covered because of lack of original
texts and samples of broadcasts. Only few are simulated on 100% originial texts, few are
radioteletype or internet versions of given MIB or meteo source of that meteo station.
I think it is quite original as I remeber these broadcasts from 1990s. All broadcasts are
listed in WX_NX.TXT file.

  If no WX message is present station just sending constantly announcements of broadcast within its
transmitting sked window. This will be added later. It is not problem to generate general weather
broadcasts for given geographical area but I want hold it as original as possible.


Meteo CodesCodes used in Meteo Broadcasts and description of old F codes
Meteo FM CodesDescription of new FM codes
WX_NX.TXTSimulated Weather and Navigational Broadcasts
Meteo LinksLinks to various meterological manuals and documents
WX DECODERMy simple program to decode FM-23 messages


  • Covering all other meteo codes
  • still adding skeds


  • samples of broadcasts not covered in RARS
  • any additional informations, etc...


    [1] International List of Selected, Supplementary and Auxiliary Ships, WMO OMM No. 47. TP. 18, 1966
    [2] Manual on Codes, International Codes Volume I.1, Annex II to the WMO Technical Regulations, WMO-No. 306
    [3] - VOS Coast Stations
    [4] WMO/OMM No.9 - Weather Reporting
    [5] 1943 Radio Weather Aids To Navigation - Radio Weather Broadcasts, Notice to Mariners No.32 of 1943, USN Hydrographic Office
    [6] MAFOR -
    [7] NOAA/NWS Catalog of Meteorological Bulletins
    [8] Weather Service for Merchant Shipping, Sixteenth Edition, Sep 1970, Silver Spring
    [11] Radio Aids To Navigation 1930, USN Hydrographic Office
    [12] Radio Weather Aids H.O. Pub. No. 118