Editing Longwave (section)

==Broadcasting <span class="anchor" id="longwave_broadcasting_anchor"></span>==
Longwave is used for broadcasting only within ITU Region 1. The long-wave broadcasters are located in Europe, North Africa and [[Mongolia]]. 

Typically, a larger geographic area can be covered by a long-wave broadcast transmitter compared to a [[medium-wave]] one. This is because ground-wave propagation suffers less [[attenuation]] due to [[ground conductivity]] at lower frequencies.<ref>[http://www.itu.int/rec/R-REC-P.368-9-200702-I/en ''Ground-wave propagation curves for frequencies between 10 kHz and 30 MHz.''] {{webarchive|url=https://web.archive.org/web/20120824233616/http://www.itu.int/rec/R-REC-P.368-9-200702-I/en |date=24 August 2012 }} ITU-R Recommendation P.368-9</ref>

Many countries have stopped using LW for broadcasting because of low audience figures, a lack of LW on new consumer receivers, increasing interference levels, the energy inefficiency of AM and high electricity costs at transmitters. 

In 2014 and 2015 Russia closed all of its LW broadcast transmitters.<ref>{{cite news |date=7 May 2018 |title=Russia says 'So long, long-wave' |work=BBC News |url=https://www.bbc.co.uk/news/blogs-news-from-elsewhere-25683656 |url-status=live |archive-url=https://web.archive.org/web/20170223232422/http://www.bbc.co.uk/news/blogs-news-from-elsewhere-25683656 |archive-date=23 February 2017 |access-date=7 May 2018 }}</ref> 

As of 2024 more than half of LW frequencies are unoccupied and some of the remaining services are scheduled for closure. [[BBC Radio 4]] (UK) announced that it will stop distinct programming for LW broadcasts in 2024 in an effort to transition listeners to other means of listening. A closure date for LW broadcasts has not yet been announced.<ref>[https://www.bbc.co.uk/mediacentre/articles/2023/bbc-radio-4-long-wave-transition BBC Radio 4 begins information campaign to transition listeners from Long Wave]</ref> The [[radio teleswitch]] service for electricity meters is broadcast with the long wave signal.  In October 2024 the Radio Teleswitch Taskforce said that it will end on 30 June 2025.<ref>{{cite web |title=End of the Radio Teleswitch Service (RTS): what we’re doing to help {{!}} Ofgem |url=https://www.ofgem.gov.uk/publications/end-radio-teleswitch-service-rts-what-were-doing-help |website=www.ofgem.gov.uk |access-date=6 December 2024 |language=en |date=3 October 2024}}</ref>

===Carrier frequencies===
With the adoption of the [[Geneva Frequency Plan of 1975]], long-wave carrier frequencies are exact multiples of 9&nbsp;kHz; ranging from 153 to 279&nbsp;kHz. One exception was a French-language station, [[Europe 1]] in Germany, which retained its prior channel spacing until the long-wave service was terminated in 2019. Other exceptions are all Mongolian transmitters, which are 2&nbsp;kHz above the internationally recognized channels.{{Clarify|date=December 2016}}

Until the 1970s, some long-wave stations in northern and eastern Europe and the Soviet Union operated on frequencies as high as 433&nbsp;kHz.<ref>{{cite book|title=Guide to Broadcasting Stations|publisher=[[Butterworth-Heinemann|Butterworth]]|edition=17th|isbn=0-592-00081-8|pages=18|year=1973}}</ref>

Some radio broadcasters, for instance [[Droitwich transmitting station]] in the UK, derive their carrier frequencies from an [[atomic clock]], allowing their use as [[frequency standard]]s.  Droitwich also broadcasts a low bit-rate data channel, using narrow-shift phase-shift keying of the carrier, for [[Radio teleswitch|Radio Teleswitch Services]].

===Long-distance reception===
Because long-wave signals can travel very long distances, some [[radio amateur]]s and [[Shortwave listening|shortwave listeners]] engage in an activity called [[DXing]]. DXers attempt to listen in to far away transmissions, and they will often send a reception report to the sending station to let them know where they were heard.  After receiving a report, the sending station may mail the listener a [[QSL card]] to acknowledge this reception.

Reception of long-wave signals at distances in excess of {{convert|17000|km|mi}} have been verified.<ref>http://www.classaxe.com/dx/ndb/rww/stats#top {{webarchive|url=https://web.archive.org/web/20160216221734/http://www.classaxe.com/dx/ndb/rww/stats|date=16 February 2016}}<!--From table for all types of signal: 2016-02-18 17487[km] 10865 81[kHz] GYN2 ENG IO84nr  Edgar J Twining (TA AUS)--></ref>

===List of long-wave broadcasting transmitters===
{{See also|List of longwave radio broadcasters}}
{{wide image|Height diagram1.gif|7500px|Height diagram of the antenna towers and antenna masts of long-wave broadcasting stations}}