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Doc. #26B
ARRL Software Radio Working Group's
Third Report to the Technology Task Force
Rev. A, July 9, 2003
1. Recent Activities
Our Working Group embarked on an extensive speaking tour this year. The focus was on making Amateur Radio operators aware of recent advancements in software radio and possibilities for the future. Venues included, but were not limited to: the Georgia Institute of Technology, Mar 10; Dayton Hamvention, May 18; Knoxville Hamfest and Electronics Exhibition, June 13; and the ARRL National Convention in Dallas, June 21. Members variously presented information about current developments in software radio.
The Dayton forum was well received and attendance was more than we expected. Feedback about it was positive and we found that interest in software radio is high and still growing. The Knoxville exhibition saw a packed room for our forum. Dallas was also a delightful session, again with a packed room. Present were Warren Bruene, W5OLY, of Collins Radio fame and several QEX authors.
Gerald, AC5OG's SDR-1000 has seen much success, selling out its first two production runs. Larry Dodd, K4LED, filmed the presentation at Georgia Tech. The video production, its Powerpoint files and associated audio samples have been delivered to Newington for possible inclusion in the ARRL Educational Video Series. A discussion of digital voice developments is included.
QEX continues to publish the series of member Leif Asbrink, SM5BSZ; AC5OG's was completed in 2003. Jim Scarlett, KD7O's second segment was published in March, 2003. Additionally, the results of R. Larkin, W7PUA, et al., using his DSP-10 are in the current QEX; the article has generated superlative comments from readers. Others have been invited to write. The books Experimental Methods in RF Design, Digital Signal Processing Technology and the Handbook from ARRL have helped get the word out. New material for the Handbook on software radio has been prepared for a future edition.
Links to article downloads and to software radio sites were exchanged among members and the ARRL site. Over 20,000 hits were obtained via those links to the associated sites.
2. The Next Steps
A new, state-of-the art software radio is under construction. The front-end analog-to-digital converter and digital down-converter have been married and made operational. A universal serial bus (USB) interface to a PC is being pursued.
We have discussed the adoption of a protocol between software-radio front ends and PCs. We would like to extend that beyond command and control to the exchange of high-speed digital signals for PC modulation, demodulation and other transceiver functions. We are aware of several similar projects.
We are happy to report that software radios are getting into the hands of more amateurs than ever before. Their benefits are becoming much better known. The trend toward placing the burden on PCs of handling heavy computing burdens seems to be gaining momentum and has already borne much fruit in weak-signal work, propagation research and interference reduction.
Direct-conversion technology has finally reached a point where it can rival analog techniques for receiver dynamic range. There is some concern about traditional testing methods that would incorrectly assess software-radio receiver performance. We would like to take steps to prevent such assessments and the risk that software radios be incorrectly perceived as poor performers. In addition, some members feel that ARRL reviews should comment on the availability of software download capabilities in radios, or the lack thereof. Such capabilities could be used to experiment with DSP filters, demodulators and new design topologies. Those concerns are being addressed separately by members.
The Digital Communications Conference (DCC) at Hartford in September will see many discussions of software radio. Members plan to be there.
Respectfully submitted,
Leif Åsbrink, SM5BSZ
Gary Barbour, AC4DL
Eric Blossom
Brad Brannon
Jim Scarlett, KD7O
Doug Smith, KF6DX, Chair
Gerald Youngblood, AC5OG
References:
1. Leif Åsbrink, SM5BSZ, "Linrad: New Possibilities for the Communications Experimenter, Part 3," QEX, Sep/Oct 2003 (scheduled).
2. Bob Larkin, K7PUA; Larry Liljequist, W7SZ; and Ernest P. Manly, W7LHL, "Microwave Propagation in the Upper Troposphere," QEX, Jul/Aug 2003.
3. Jim Scarlett, KD7O, "A High-Performance Digital Transceiver Design, Part 2," QEX, Mar/Apr 2003.
4. Gerald Youngblood, AC5OG, "A Software-Defined Radio for the Masses, Part 4," QEX, Mar/Apr 2003.
