By: Bill Sexton, AAA9PC/N1IN
Posted: 19 NOV 04
PnP…SMT…PLL…DSP…NBFM…TCP/IP…ALE…
The way some people see it, whenever amateur radio achieves a high-tech breakthrough we Hams lose more control over the hobby. May be they have a point. Remember when you could repair a rig with an ordinary soldering iron? When "QRZ" and "QSL" was all the jargon needed to get you on the air?
Perhaps. But at least one of the far frontiers of advanced radio communication-Automatic Link Establishment-is now in the process of being rescued from the techno-geeks to the benefit of us commo-nerds.
Volunteers in Army MARS (the Military Affiliate Radio System) are currently perfecting a software replacement for the high-priced ALE hardware operated by government agencies and the military. The goal is to control standard amateur transceivers with a plain-vanilla home computer-cum-sound card program. It is very close to realization.
There is more at stake here than merely cutting the cost of equipment. It turns out that even with price tags in five figures, commercial ALE gear isn't sufficiently flexible to handle the amateur service's emergency communications needs.
Nor is the original PC-ALE software solution invented in the late 1990s by Britain's digital radio guru, Charles H. Brain, G4GUO. His freeware program constituted a giant step forward for the penny-counting Ham community, but it never proceeded into final development. As Charles explains on his web page, he had to put it aside and get back to earning a living. (Brain described himself in an e-mail interview as "self-employed working on signals collection and analysis software.")
During the past summer, Brain, who also pioneered the digital voice protocol now being promoted commercially by AOR, shared his still-incomplete PC-ALE code with the MARS ALE team headed by Carlos Santiago AAV2AS of Naples NY. "Don't sell the executables commercially without my permission." he told Santiago, who negotiated the cost-free deal. "But you can give them away."
Santiago has assembled an impressive crew of MARS members within New York and nearby states. He is a retired telecommunications engineer as well as skilled net manager. Other participants, all FCC-licensed volunteers, include a 26-year veteran of U.S. Army communications, a former strategic planning executive at a major telecommunications company, a Defense Department contractor employee--plus a dozen or so dedicated beta testers. Such is the wealth of talent clustered in MARS.
Fairly typical of the group, MIT graduate Peter Gottlieb AAR2FE of Dobbs Ferry NY explains his interest in the project this way: "Here was something complex that I didn't know anything about. Something obscure and hard to understand. Excellent!" With his professional experience in coding and interfacing embedded microprocessors, Gottlieb is Santiago's software-writing expert.
The principle is simple enough. Basically, each station in an ALE net automatically transmits a beacon (or "sounding") at set intervals over a wide array of dedicated frequencies. All the stations in the net continuously scan these frequencies. Each receiver's computer records in memory which members of the net can be heard, on what frequency, and how well. The reception reports are constantly updated. (You can see the resemblance to APRS.)
When there's traffic to be sent, the initiating station's equipment "knows" which band is open to the addressee station and automatically links. Then the operator intervenes to send voice or digital traffic. What distinguishes PC-ALE software from the government's phone-only ALE hardware is the capacity for passing digital files (including graphics as well as text).
An early version of Brain's software has been downloadable from his personal web site www.chbrain.dircon.co.uk/pcale.html. He has lately added (but not published) a capability known as FS-1052. This U.S. Federal Standard describes an advanced digital mode required for all new HF modems acquired for government use. It is an adaptive mode, automatically adjusting throughput from 4800 bits/second down to 75 bits/second depending on band conditions.
For Hams here is the ultimate irony: ALE came into being as a replacement for trained human operators. The idea was that any authorized person could pick up the microphone and initiate a call without concern for propagation or tuning. Simpler than dialing a telephone, at least in principle.
By contrast, PC-ALE is-so far, anyway-a finicky protocol that demands a great deal of TLC. A couple of dozen parameters need to be set and monitored on computer, sound card and transceiver. Not automatic by a long shot.
Given that fact and the crowded nature of the amateur spectrum, ALE isn't likely to win broad application among Hams. Even if specific frequencies could be legally set aside on the amateur bands for ALE scanning, the presence of several hundred stations all sounding automatically would create insufferable QRM.
The more likely use is in special applications such as emergency networks, for example linking MARS stations with National Guard or Reserve units on government frequencies. In Army MARS, ALE participants must obtain individual authorization from headquarters to use the 10 military channels allocated for MARS (sprinkled between 3 and 21 MHz).
The Air Force was among the first users of ALE, primarily for phone patching with aircraft aloft. The mode came to the Army MARS general membership via SHARES, the federal SHAred RESources network linking government agencies (including MARS) via HF radio. MARS is the biggest source of operators in SHARES.
Frank Guptill AAR1DD, a former Connecticut state director for Army MARS, encountered ALE while serving as Northeast Regional Net Control of SHARES. After observing an imported portable ALE rig manufactured for sale to government agencies--at a cost in the low thousands--he purchased a unit for his own use.
Frank came to Ham radio by way of the U.S. Navy. As a World War II radioman aboard Curtiss SB2C Helldiver dive-bombers he was shot down at sea, earned the Distinguished Flying Cross, three Air Medals and a Purple Heart. Now retired from a career of petroleum engineering, he serves as ALE net control for the national SHARES system from his home station in West Hartland CT.
One day Carlos Santiago heard Guptill discussing ALE on a MARS training net and asked about it. "I downloaded the software," Santiago recalls. "After playing with it I approached [New York state MARS director] Steve Pertgen last October about organizing a training net." Approval came through channels and in January 2004 the net was launched, with members of Air Force and Navy-Marine Corps MARS invited to join.
Brain's early version 1.03 of PC-ALE proved fascinating but terribly slow. Configuring the participating stations one by one was an on-air chore that took several months. Then in April 2004, Brain e-mailed a new version 1.05 incorporating the speedy FS-1052 modem utility. With that the MARS project really took off.
By June, Santiago and Co. were ready to support the nationwide U.S. Army communications exercise "Grecian Firebolt 2004" with an operational ALE net. Eleven stations from New York, New Jersey, Connecticut, Massachusetts and Virginia handled 61 simulated emergency messages on a total of 19 ALE nets. It was an exhilarating time.
"We were able to make some interesting breakthroughs in a short period of time," says military retiree Dick McNutt AAR3AN, a veteran digital training officer in MARS. "The culmination was Grecian Firebolt 2004 where all the ALE operators on the East Coast came together in support of the operation."
Come August, Brain turned over the beginnings of version 1.06 plus his unfinished computer code. The MARS team has been working on it ever since, intending to complete the software over the winter.
Team leader Santiago cites several members to illustrate the variety of skills and the dedication now at work on PC-ALE:
Carver Washburn AAR2JQ of Wayne NJ, for instance, has operated a weekly clinic net to assist new participants getting their rigs configured, an awesome task at the start. He comes to that role naturally-his father was a professor at MIT. Carver holds a Columbia MS in electrical engineering and put in eight years as an officer in the Army Signal Corps and 10 years as New Jersey state MARS director. His pre-retirement career was program management in aerospace and telecommunications.
Steve Hajducek AAR2EY of Lakewood NJ provided the original contact with Charles Brain and, says Santiago, participates heavily in on-air testing as well as serving as a net control. Steve's Dad had been a commo sergeant overseas during World War II. Which probably explains how Steve, at only six years of age, happened to be given a Hammarlund SP-200 receiver. He followed his father's lead in communications and computer-assisted design.
Dick McNutt, of Williamsburg VA has been training Virginia MARS members in the digital modes for the past 10 years. He is one of the principal ALE debuggers. His 26 years of military service included assignment to the Signal Corps and then Aviation Special Operations, with three tours in Vietnam.
Santiago also has an interesting story to tell. He was born at Arecibo, PR, site of the world's biggest radio telescope. He learned about radio from his father who was an avid shortwave listener. Carlos's professional career ranged from AT&T transmission and central office maintenance to submarine cable testing and telecommunications system design. Since retiring and joining MARS in 1999, he has become state ALE Operations Officer.
As for Charles Brain, who started it all: His radio career began at age 11 with a Christmas present from his parents. It was a book called "365 Things to Do." One of the things to do was building a crystal set . . .
(Bill Sexton is national public awareness coordinator of Army MARS. .This column was first published in the December 2004 issue of WorldRadio magazine.)