Introduction to Using Winlink Over VHF or UHF - …

1 Digital NotesPage 1 Digital Notes01000100 01101001 01100111 01101001 01110100 01100001 0110110001001110 0110111 1 01110100 01100101 01110011 Using digital applications in amateur radioWhat is the Winlink systemWinlink 2000 (often referred to as WL2K , orsimply Winlink ) is a last mile , radio-based emailtransport system developed and sponsored by theAmateur Radio Safety Foundation, Inc. ( ARSFI ),its many donors and numerous Winlink Development Team, , describes Winlink as follows: Winlink 2000 is a worldwide radio messagingsystem that takes advantage of the Internet whereverpossible while retaining the ability to function with-out major parts of it. It combines the best attributesof wireless communications and the Internet to al-low remote users to send and receive email to andfrom correspondents on the Internet as well as otherusers of the system.

2 The synergy of this combina-tion provides fast Internet message forwarding world-wide with the long reach of radio links to places with-out normal Internet service. The system is carefullydesigned to provide important side benefits: To operate without the Internet over major por-tions of the earth. To minimize the spectral footprint needed to ac-complish the task. Winlink provides the capability to exchangeemail at locations without Internet connectivity, in-cluding during emergencies. In such situationsWinlink may be utilized to provide email capabilityboth within the affected area and to the outsideworld .How Winlink worksThe Winlink system consists of numerous Ra-dio Mail Server ( RMS ) stations maintained on avolunteer basis by licensed Amateurs. RMS Packetstations operate on the VHF or UHF bands whileRMS HF stations operate on the high RMS station is connected through theInternet ( Using the Telnet protocol) to the Winlinksystem, a network of five redundant Common Mes-sage Servers ( CMS ).

3 The geographically-dispersedCMS are located in San Diego, Brentwood (Tennes-see), Halifax, Perth and Vienna. Messages to or fromusers are normally transmitted through one of theCMS Using a RMS station. Users with an activeInternet connection may connect directly to a CMSusing a Telnet connection, or may send and receiveemail Using a browser-based Web-mail messages are handled within the Winlinksystem in accordance with established Internet stan-dards, allowing for the seamless exchange of mes-sages with any standards-compliant system or de-vice and operation of a RMS station, as wellas access over the HF bands, is beyond the scope ofthis to Using Winlink over VHF or UHFD igital NotesPage 2 Requirements for VHF or UHF accessConnecting with a RMS Packet station requires: A VHF or UHF radio. While an HT may be ad-equate to connect with a nearby RMS Packet sta-tion , a base or mobile transceiver providing ad-ditional power may be required.

4 An appropriate antenna system. A terminal node controller ( TNC ) or sound cardinterface, together with appropriate cables for con-nection to your radio and computer. A personal computer. The computer need not beof recent vintage; any moderately powerful com-puter will usually be adequate. While most usersseem to be operating Windows-based systems, andmost software development is focused in that di-rection, software is available for both Linux andMac systems. Appropriate user software of your Node ControllersConnections to a RMS Packet station on VHFare usually made at 1200 baud, while those made onUHF are usually at 9600 baud. Note that a 9600baud connection requires both stronger signalstrength and less interference to be VHF or UHF connection to Winlink is madeusing the packet data standard. Thus a TNCsupporting the proprietary Pactor 1, 2 or 3 protocolsused for HF digital communications is not less expensive TNC complying with either the KISS or similar TNC2 (promulgated by TucsonAmateur Packet Radio, Inc.)

5 Standards will be planned operations are limited to VHF only asingle-speed, 1200 baud TNC is card interfaces, in particular external de-vices such as the SignaLink and similar products,may also be used successfully in many in mind, however, that the setup and configu-ration of a sound card-based solution often presentsmore of a challenge than use of hardware User SoftwareThere are a number of software options avail-able to users for connecting with a RMS Packet sta-tion or CMS. This overview will focus on thoseavailable for a Windows environment. All programsdiscussed are available from the Internet without ExpressA relatively recent product, RMS Express issupported by ARSFI as part of Winlink Express provides a complete email messagingsystem similar to Outlook or Outlook Express. Alimited number of callsign or tactical accounts aresupported.

6 Address book and message attachmentfunctionality is addition to VHF or UHF packet connectionaccess, direct connection to a CMS via Telnet is avail-able, as well as HF connection Using the various ver-sions of Pactor. Connection Using the HF WINMOR protocol Using a sound card interface is also popular hardware TNCs are supported byRMS Express, including the various Kenwood ra-dios with an integrated TNC. KISS TNCs can oftenbe used, and some users have reported success usingsound card interfaces in connection with AGWP acket Engine ( AGWPE ).Figure 1 An interior view of TNC-X, one of many availableKISS mode TNCs. Photo from the manufacturer s Web NotesPage 3 RMS Express requires Microsoft .NET in-stalled on the 2 The main display of RMS Express showing messagefolders at left, and individual messages at right with a mes-sage preview and supported independently ofARSFI, Airmail is an email client providing inbox,outbox, address book and attachment supports only a single callsign account; tac-tical accounts are not an older program, Airmail supports awide variety of hardware TNCs, including those us-ing KISS mode, and sound card interfaces, either na-tively or through use of AGWPE.

7 Use of AGWPE does require the Airmail-to-Packet Engine ( AMPE ) supports direct Telnet connection to aCMS, VHF or UHF packet connections and HF con-nections Using Pactor. WINMOR is not supportedat this considerationsAt 1200 baud on VHF, or even 9600 baud onUHF, radio-based email is slow in comparison toavailable fixed Internet connections. But when allelse fails , or there is simply no other means avail-able, it is a viable option for sending and receivingemail throughput is improved by keepingemail messages as concise as possible. Use plainFigure 3 Paclink s main display showing activity to and fromthe CMS (via Telnet) at left, and local message activity (viaSMTP and POP3) at is another program from ARSFI and theWinlink Development Team. Unlike RMS Express,Paclink does not provide email client (inbox, outbox,address book, etc.)

8 Functionality. Instead, Paclink isa mail server, providing an operator with the abilityto support multiple email users on a local area net-work. With relatively minor computerreconfiguration, users can send and receive emailmessages through Paclink Using their regular emailclient, such as Outlook. Attachments are supported,and Web browser-based access may be Paclink may provide users at a servedorganization with seamless and familiar email ac-cess, there are potential issues. The most significantis that users may not fully comprehend the limita-tions of radio-based email and attempt to utilize thesystem as they normally would, possibly overload-ing the available bandwidth with large messages orattachments. When considering the use of Paclink,this concern should be addressed through the use ofprogram limits and adequate end-user NotesPage 4 Digital Notes covers topics related to the use of digital applications in amateur radio, with a focus of emer-gency communication, and represent the views of Gary S.

9 Wong, W6 GSW. A CPA and technology consult-ant, W6 GSW holds an Amateur Extra license. Located in Southern California (DM04WB), he is a memberof the Amateur Radio Relay League, an ARRL accredited Volunteer Examiner and an Emergency Coordi-nator for the Northeast District, Los Angeles Section of the Amateur Radio Emergancy 2011 Gary S. Wong (W6 GSW). All rights request permission prior to reproduction or dstribution of this W6 GSW by email at 2011text messages and small attachments whenever pos-sible. Winlink normally utilizes B2F (Level B2 FBB) compression, which can reduce the size of plaintext data by as much as half. Binary data, such asgraphic or Adobe document files, achieve signifi-cantly lower compression transmitting email attachments, keepthem as small as possible by reducing their resolu-tion or document size. Winlink enforces a maxi-mum compressed message size of 120,000 charac-ters; RMS station operators may establish their own,smaller, are sample average message trans-fer times over VHF at 1200 baud with an excellentsignal (and thus no packet errors or retrys): Text of the Preamble to the Constitution, 504 char-acters including email overhead, compressed to383 characters, 27 seconds.

10 Text of the Lord s Prayer, 555 characters includ-ing email overhead, compressed to 404 charac-ters, 32 seconds. Text of Psalm 23, 778 characters including emailoverhead, compressed to 538 characters, 34 sec-onds. Text of the Declaration of Independence, 9518characters including email overhead, compressedto 4687 characters, 1 minute, 24 seconds. Brief text email with 66k Adobe pdf attachment,66523 characters including email overhead, com-pressed to 63733 characters, 16 minutes, 35 Internet links The Winlink system RMS Express, Paclink and related software Airmail AGW Packet Engine Airmail-to-Packet Engine Sound card packet information 4 Airmail s message index showing the folder tree atleft and individual messages at right.