DAPNET: Difference between revisions

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[[File:Ham-pager.jpg|thumb|right|DAPNET as of July 2023]]

==History==

A similar ham radio project called FunkrufMaster was quite popular around 2000. It was based on [[AX.25]]-technology and the former Packet Radio Network. Because of the upcoming HAMNET- and [[Internet Protocol|IP-Protocol]] era, a successor was needed. Members of the ham radio activity group at [[RWTH Aachen University]] designed and developed '''DAPNET''' from scratch as a modern software approach. <ref>[{{Cite web |url=https://www.ralfwilke.com/index.php/en/about-me |title=Ralf Wilke - About] |access-date=2023-07-21 |archive-date=2023-07-21 |archive-url=https://web.archive.org/web/20230721225846/https://www.ralfwilke.com/index.php/en/about-me |url-status=dead }}</ref> As of March 2018, over 90 transmitters were already in permanent operation, and the coverage area included parts of [[Germany]], the [[Netherlands]], [[Belgium]], and [[Switzerland]].,<ref>[https://hampager.de/dokuwiki/doku.php?id=dapnetoverview DAPNET Overview]</ref>, with [[Raspberry Pi]]-based personal hotspots extending coverage around the world.<ref>[https://hampager.de/dokuwiki/doku.php?id=mmdvm]</ref>.

==Technical specifications==

The recommended frequency for DAPNET is 439.9875&nbsp;MHz,<ref>[https://hampager.de/dokuwiki/doku.php?id=dapnetfrq Recommended frequencies]</ref> which is part of the [[70-centimeter band]] dedicated to amateur radio use. The transmitters are networked, some via HAMNET, some via the Internet. The standard paging protocol [[POCSAG]] is used for message transmission. For a low-power transmitter you can use [[Raspberry Pi]] with {{proper name|unipager}}<ref>[https://github.com/rwth-afu/UniPager GithubGitHub: UniPager]</ref> and MMDVM-modem<ref>[https://www.researchgate.net/publication/312934460_Development_of_a_Decentralized_Paging_Transmitter_Network Development of a Decentralized Paging Transmitter Network]</ref> installed, and to make the coverage area several miles, a radio amplifier needs to be added to its output.<ref>[https://hampager.de/dokuwiki/doku.php?id=raspager RasPager - Simple low-power Transmitter]</ref> The coverage area of the transmitter can be up to 20 km (12 miles), depending on the terrain and the height of the antenna.

==Receivers==