Editing Numbers station (section)

== Interference ==

=== Interfering with other broadcasts ===
The North Korean foreign language service [[Voice of Korea]] began to broadcast on the E03 [[Lincolnshire Poacher (numbers station)|Lincolnshire Poacher]]'s former frequency, 11545&nbsp;kHz, in 2006, possibly to deliberately interfere with its propagation.{{citation needed|date=October 2017}} However, Lincolnshire Poacher broadcasts on three different frequencies, and the remaining two, have not been interfered with. The apparent target zone for the Lincolnshire Poacher signals originating in Cyprus was the Middle East, not the Far East, which is covered by its sister station, E03a [[Cherry Ripe (numbers station)|Cherry Ripe]].<ref>{{Cite web|url=http://priyom.org/number-stations/english/e03a|title=E03a|website=Priyom.org|language=en|access-date=2017-06-17}}</ref><ref name="karoo514">{{cite web |url=http://www.simonmason.karoo.net/page514.htm |title=Secret Signals |publisher=Simonmason.karoo.net |access-date=7 November 2015 |archive-date=10 February 2016 |archive-url=https://web.archive.org/web/20160210010724/http://www.simonmason.karoo.net/page514.htm |url-status=dead }}</ref>

On 27 September 2006, amateur radio transmissions in the 30&nbsp;m band were affected by an S06 "Russian Man"<ref>{{cite web |url=http://priyom.org/number-stations/slavic/s06 |title=S06|website=Priyom.org |language=en |access-date=2017-06-17}}</ref> numbers station at 17:40 UTC.<ref name="karoo514" />

In October 1990, it was reported that a numbers station had been interfering with communications on 6577&nbsp;kHz, a frequency used by air traffic in the Caribbean. The interference was such that on at least one monitored transmission, it blocked the channel entirely and forced the air traffic controller to switch the pilot to an alternative frequency.<ref name="karoo514" />

A [[BBC]] frequency, 7325&nbsp;kHz, has also been used. This prompted a letter to the BBC from a listener in [[Andorra]]. She wrote to the [[BBC World Service|World Service]] ''[[Waveguide]]'' programme in 1983 complaining that her listening had been spoiled by a female voice reading out numbers in English and asked the announcer what this interference was. The BBC presenter laughed at the suggestion of spy activity. He had consulted the experts at [[Bush House]] (BBC World Service headquarters), who declared that the voice was reading out nothing more sinister than snowfall figures for the ski slopes near the listener's home. After more research into this case, shortwave enthusiasts are fairly certain that this was a numbers station being broadcast on a random frequency.<ref>{{cite web |url=http://www.simonmason.karoo.net/page34.html |title=Secret Signals |publisher=Simonmason.karoo.net |access-date=26 August 2010 |archive-url=https://web.archive.org/web/20070220145145/http://www.simonmason.karoo.net/page34.html |archive-date=20 February 2007 |url-status=dead }}</ref>

The Cuban numbers station "HM01" has been known to interfere with shortwave broadcaster Voice of Welt on 11530&nbsp;kHz.<ref>{{Citation|last=Anthony Spinelli|title=HM01 and Voice of Welt 11530 AM 10 18 2018 1743z|date=2018-10-18|url=https://www.youtube.com/watch?v=JgzyVNGdbzM |archive-url=https://ghostarchive.org/varchive/youtube/20211211/JgzyVNGdbzM| archive-date=2021-12-11 |url-status=live|access-date=2018-11-26}}{{cbignore}}</ref>

=== Attempted jamming ===
Numbers station transmissions have often been the target of intentional jamming attempts. Despite this targeting, many numbers stations continue to broadcast unhindered. Historical examples of jamming include the E10 (a station thought to originate from Israel's [[Mossad]] intelligence agency) being jammed by the "Chinese Music Station" (thought to originate from the [[People's Republic of China]] and usually used to jam "[[Sound of Hope]]" radio broadcasts which are anti-CCP in nature).<ref>{{cite web |url=http://www.swldxer.co.uk/yhf-dec06.wma |title=Chinese Music Station |format=Windows Media Audio |access-date=16 July 2012 |archive-url=https://web.archive.org/web/20120308232621/http://www.swldxer.co.uk/yhf-dec06.wma |archive-date=8 March 2012 |url-status=usurped }}</ref>