- 2182 kHz
The radio frequency of 2182 kilohertz (kHz) is the international calling and distress frequency for voice maritime communication (radiotelephony) on the marine MF bands. It is analogous to Channel 16 on the marine VHF band.
Modulation
Transmissions on 2182 kHz should use
single-sideband modulation (SSB) (uppersideband only). That said,Amplitude modulation (AM), and some variants in between the two, such as vestigial sideband, are still in use. These are used mainly by vessels with older equipment installed and by some coastal stations in an attempt to ensure compatibility with older and less sophisticated receivers afloat.GMDSS
2182 kHz forms an essential part of the
Global Maritime Distress Safety System (GMDSS). It has an associated DSC frequency at 2187.5 kHz.Range
Unlike Marine VHF which is limited to about convert|50|nmi|km|-1 range, communications on 2182 kHz and nearby frequencies have a typical range of around convert|150|nmi|km|-1 during the day and 500 (or more) nautical miles at night [http://www.weather.gov/om/marine/mfvoice.htm] .At night a well equipped station can achieve intra-continental communication, but this range can be severely limited insummer because of
static caused by lightning.There are many other marine frequencies, including distress and calling frequencies, in the HF bands, up to and including worldwide coverage with the right conditions. In addition to these, satellite technology can provide worldwide communications for vessels at sea.
ilence Period
Twice each hour, all stations listening on 2182 kHz are required to maintain a strictly enforced three-minute silence period, starting at h+00 and h+30. As a visual aide-memoire a typical clock in a ship's radio room would have these silence periods marked by shading the sectors between h+00 to h+03 and h+30 to h+33 in green. Similar sectors at h+15 and h+45 may be marked in red for a corresponding silence period on
500 kHz , although this is no longer an active marine distress or listening frequency.Licencing
In order to operate a marine radio transceiver on 2182 kHz, the operator must hold a
GMDSS Long Range Certificate , which requires success on a wider syllabus than that of theGMDSS Short Range Certificate that is necessary for Marine VHF use. In either case, though, an unqualified operator would not be prosecuted for the use of either rig in what turns out to be a genuine distress situation. (In the United States comparable certificates would be the GMDSS Operator and the GMDSS Restricted Operator licenses.)ee also
*
Marine VHF radio
*Mayday (distress signal)
*Pan-pan
*Securite
*Global Maritime Distress Safety System
*500 kHz External links
* [http://www.itu.int/home/index.html International Telecommunication Union]
* [http://www.mcga.gov.uk/c4mca/mcga-mld-page.htm?textobjid=43E2ED43ADD24D4A Maritime and Coastguard Agency]
* [http://www.opsi.gov.uk/si/si1992/Uksi_19920003_en_4.htm Merchant Shipping Regulations]
* [http://www.shipsclockshop.co.uk/shipsclock/default.asp?m=3265 Example of a Radio Room Clock]
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