What is ALE? Ham Radio ALE. How ALE Works. Selective Calling, Automatic Link Establishment.
Adapted from the Article: ALE on HF in the Amateur Radio Service. Selective Calling and Automatic Linking for Voice, Text, Image, CW, and Data by Bonnie Crystal KQ6XA What is ALE? ALE is the humorous acronym for the lofty-sounding Automatic Link Establishment. With the capability to call up a specific station, a group of stations, a net... or just CQ, ALE is a versatile system for connecting operators for voice, data, text, instant messaging, or image QSOs. A radio operator initiating a call, can within minutes have the ALE automatically pick a frequency that has a good propagation path. It signals the operators on both ends, so they can begin communicating with each other immediately. In this respect, it can eliminate the longstanding need for repetitive calling on pre-determined time schedules and monitoring static on HF. It is a great tool for finding optimum propagation between stations in real-time, while avoiding guesswork, beacon listening, and complicated HF prediction charts altogether. These days, ALE is most commonly used for hooking up operators for voice QSOs on SSB and data QSOs with various modem techniques, but there are many other useful features. ALE in Ham Radio For the past 4 years, a group of Amateur Radio operators has joined together for experiments and communications using ALE and Selective Calling. The number of hams has grown from just a handful active in 2001, to the hundreds of enthusiasts in it today. Some are following the traditional ham curiosity to explore interesting aspects of communications; others are developing dependable HF nets, or just using it to keep in touch with a circle of ham friends. The need to call up emergency nets or inter-operability and liason with government HF systems has led many hams to adopt the government ALE standard, called FED-STD-1045 or MIL-STD 188-141. This standard caught on slowly in the ham community, initiated by a few operators with limited government surplus gear and some with expensive commercial equipment having embedded ALE or hardware controllers. Now, with a ham HF transceiver, a computer as the controller, and an appropriate antenna system, hams can harness the power of ALE. How ALE Works Each ham radio ALE station uses the operator's callsign as an address in the ALE controller. When not actively in a QSO with another station, each HF SSB transceiver constantly scans through a list of frequencies, listening for its callsign. To reach a specific station, the caller simply enters the callsign just like dialing a phone number. The ALE controller selects the best available frequency and sends out brief selective calling signals containing the callsigns. When the distant scanning station detects the first few characters of its callsign, it stops scanning and stays on that frequency. The two stations' ALE controllers automatically handshake to confirm that a link is established and they are ready to communicate. The receiving station, which was muted up until now, will typically turn on the speaker, emitting an audible alarm and visual alert for the receiving operator of the incoming call. It also indicates the callsign of the linked station. The operators then can talk in a regular QSO using any mode they want. At the conclusion of the QSO, one of the stations sends a disconnect signal to the other station, and they each return their ALE stations to the scanning mode. Some military / commercial HF transceivers are available with ALE options. Amateurs commonly use Charles G4GUO's PCALE soundcard software interfaced to a ham transceiver via RS-232 CAT port, multi-frequency antenna. ALE Using a Computer as the Transceiver Controller Unit Charles Brain G4GUO, released a soundcard PC program for ALE appropriately named PCALE. Charles is to be commended for his wonderful generosity and technical achievement. By doing this, he effectively opened up ALE to the non-professional user at low cost. The availability of PCALE in various improving versions made it possible for more amateur radio operators to start experimenting with ALE. Download site: http://hflink.com/beta Ham Group for Coordinating ALE During 2001, the author is this article and several other hams in USA started using PCALE, at the suggestion of Trish WA6UBE. Trish's already-operational Motorola Micom 2R transceiver (with embedded ALE) became one of the center points for testing and linking. In December 2001, from this core of early ALE ham operators, an international group called HFLINK was founded. The purpose of HFLINK would be to further the development of methods and coordination for use of ALE and Selective Calling in HF Amateur Radio. The HFLINK group worked out guidelines and ways to adapt ALE to ham use. The scanning frequencies essential for effective ALE operation evolved with world bandplans and became HFLINK channel lists. What is the Bandwidth and Baud of the ALE Signal? The ALE (MIL-STD 188-141B or FED-STD-1045) signal is transmitted at 125 baud. The "necessary bandwidth" is 1.75 kHz. The occupied bandwidth is about 2.16 kHz at -23dBc. The ALE signal is 8FSK (8 Frequency Shift Keyed). 8 discrete tone frequencies are spaced 250 Hz apart from 750 Hz to 2500 Hz at audio baseband. Only one tone is present at any instant (8mSec/tone). The bandwidth is similar to PACTOR-III. The ALE signal bandwidth is suitable for transmission via HF transceivers through a standard SSB audio/RF chain with an IF bandwidth of about 2 kHz or more. Using ALE in USA USA hams can currently use ALE's Selective Calling and Alerting features in the PHONE subbands, and most of the features of ALE keyboarding and data exchange in the DATA subbands. PHONE band transmissions fall under the FCC rule's statement: "ยง97.3 Definitions. "Incidental tones for the purpose of selective calling or alerting or to control the level of a demodulated signal may also be considered phone." HFLINK Group The HFLINK group is an international exchange of information for radio operators using ALE and Selcall with transceivers, antenna systems, hardware and software controllers; development of HF communications networks utilizing ALE with SSB or Digital; ALE for organizations, Emergency/Relief operations; development of Automatic Linking and Selective Calling operating methods applicable to Amateur Radio Service; and ionospheric propagation research. A growing number of hams are utilising ALE, and the application of it is especially good for emergency operations. There are also several types of transceivers which have ALE in them. This has included expensive Codan, Mobat, and Harris transceivers. But, a new ALE transceiver by ICOM, the IC-F7000, is now a cost effective solution for amateur use. http://www.icomamerica.com/products/land_mobile/f7000/ HFLINK group has developed another method for emergency field operators to enter an ALE network without ALE equipment. Any operator with a normal HF SSB transceiver can call and connect with an ALE-equipped station, simply by playing pre-recorded ALE audio on an inexpensive MP3 music player. The MP3 player's earphone is held up to the SSB transceiver's microphone. It is possible now to have a very dependable local area, nationwide, or worldwide HF networks of amateur stations for emergency/relief purposes using SSB voice and data. Similar HF ALE systems are already in use by various governments and private organizations. The ALE frequency list for International Amateur Radio Service is at the bottom of this message. For more information: http://hflink.com 73---Bonnie KQ6XA -------------- ALE / SELCALL for International Amateur Radio Service =========================================================== [CH] kHz | SSB | Common Use | Description | =========================================================== [00] 1845.0 USB Voice/Data International; Emergency/Relief; DX; Regional; Local [01] 1996.0 USB Voice/Data Regional; Local [02] 3565.0 USB Data/Voice Regional; Local [03] 3626.0 USB Data/Voice Regional; Local [04] 3791.0 USB Voice International; Emergency/Relief; DX; Regional; Local [05] 3996.0 USB Voice Regional; Local [06] *5371.5 USB Voice International; Emergency/Relief; Regional; Local [07] *5403.5 USB Voice/Data International; Emergency/Relief; Regional; Local [08] 7065.0 USB Data/Voice International; Regional; Local [09] 7102.0 USB Data/Voice International; Regional; Local [10] 7165.5 USB Voice International; Emergency/Relief; Regional; Local [11] 7296.0 USB Voice Regional; Local [12] 10136.5 USB Data / Voice Regional; Local [13] 10145.5 USB Data International; Emergency/Relief; Regional; Local [14] 14109.5 USB Data International; Regional; Local [15] 14342.5 USB Voice International; Emergency/Relief; Regional; Local [16] 14346.0 USB Voice International; Regional; Local [17] 18106.0 USB Data International; Regional; Local [18] 18127.5 USB Voice International; Emergency/Relief; Regional; Local [19] 18157.5 USB Voice International; Regional; Local [20] 21157.5 USB Data International; Regional; Local [21] 21437.5 USB Voice International; Emergency/Relief; Regional; Local [22] 24926.0 USB Data International; Regional; Local [23] 24977.5 USB Voice International; Regional; Local [24] 28146.0 USB Data International; Regional; Local [25] 28327.5 USB Voice International; Emergency/Relief; Regional; Local =========================================================== [Note 1] All channels use "USB" Upper SideBand (including frequencies below 10MHz). USB conforms to international standards for ALE / Selcall, and enables compatibility with commercial transceivers. [Note 2] This Channel List is designed for international, regional, and local use in the Amateur Radio Service. All channels are subject to the different rules, regulations, and bandplans of the region and local country of operation. It is the responsibility of every operator to maintain the highest technical and ethical standards for all transmissions. Some channels or modes in the list may not be available in every country. The HF spectrum is a shared resource, so there is no guarantee that a channel is clear in a local area or region. [Note 3] Recommended scan rate: 2 channels per second. Recommended initiating call duration: approximately 15 to 20 seconds. [Note 4*] The 5MHz channels' use and frequencies may vary in each country. Although 5MHz ALE and SELCALL transmissions are authorised in some countries, USA does not yet allow it on 5MHz. Therefore, operators in USA may receive monitor the 5MHz channels, but care should be taken to lock out the transmitter from making ALE or Selcall transmissions (except in case of an extreme Emergency). [Note 5] HFLINK is an international resource: for radio operators using ALE Automatic Link Establishment and SELCALL Selective Calling; for the development of Emergency/Relief operational networks; and for the development of ALE operating methods applicable to Amateur Radio Service. HFLINK is the Frequency and Address Coordination group for Amateur Radio ALE and Selective Calling. All coordination is on a voluntary basis. [Date] Effective on 01 August 2005 (01/08/05), this supersedes all previous channel lists. [Version] HFLINK2005G [Print Chart] For a printer-friendly chart of this list: http://hflink.com/channels/hflinkprint.html The K3UK DIGITAL MODES SPOTTING CLUSTER AT telnet://208.15.25.196/ More info at http:///www.obriensweb.com Yahoo! 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