ARRL AMATEUR RADIO AMATEUR the National Association for Association National the TH-F6A(QEX):QST Template 11/10/09 1:53 PM Page 1
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The national association for ARRL AMATEUR RADIO 225 Main Street Newington, CT USA 06111-1494 WWW.RADiOSCAMATORUL.Hi2.RO WWW.GiURUMELE.Hi2.RO 5 $ TH-F6A(QEX):QST Template 11/10/09 1:53 PM Page 1 WWW.RADiOSCAMATORUL.Hi2.RO WWW.GiURUMELE.Hi2.RO KENWOOD U.S.A. CORPORATION Communications Sector Headquarters 3970 Johns Creek Court, Suite 100, Suwanee, GA 30024 Customer Support/Distribution P.O. Box 22745, 2201 East Dominguez St., Long Beach, CA 90801-5745 Customer Support: (310) 639-4200 Fax: (310) 537-8235 ADS#36709 January/February 2010 About the Cover QEX (ISSN: 0886-8093) is published bimonthly US Military Academy Cadet Thomas Dean, in January, March, May, July, September,WWW.RADiOSCAMATORUL.Hi2.RO and KB1JIJ, describes a spread spectrum transmitter November by the American Radio Relay League, he developed as a digital logic class project. Built 225 Main Street, Newington, CT 06111-1494. on an Altera DE2 Development and Education Periodicals postage paid at Hartford, CT and at additional mailing offices. Board with a Cyclone II FPGA, the transmitter POSTMASTER: Send address changes to: demonstrates some principles of spread QEX, 225 Main St, Newington, CT 06111-1494 spectrum systems and software defined radio Issue No 258 transmitters. Harold Kramer, WJ1B Publisher Larry Wolfgang, WR1B In This Issue Editor Lori Weinberg, KB1EIB Assistant Editor Zack Lau, W1VT Features Ray Mack, W5IFS Contributing Editors Production DepartmentWWW.GiURUMELE.Hi2.RO Amateur Radio Astronomy Projects Steve Ford, WB8IMY By Jon Wallace Publications Manager 3 Michelle Bloom, WB1ENT Production Supervisor Sue Fagan, KB1OKW Graphic Design Supervisor A Digital Frequency Hopping Spread Spectrum Transmitter By Cadet Thomas Dean, KB1JIJ David Pingree, N1NAS 9 Senior Technical Illustrator Advertising Information Contact: Janet L. Rocco, W1JLR Experimental Determination of Ground System Performance Business Services 860-594-0203 – Direct for HF Verticals—Part 7 800-243-7768 – ARRL 18 By Rudy Severns, N6LF 860-594-4285 – Fax Circulation Department Cathy Stepina, QEX Circulation Offices Waveguide Filters You Can Build—and Tune—Part 2 225 Main St, Newington, CT 06111-1494 USA 20 By Paul Wade, W1GHZ Telephone: 860-594-0200 Fax: 860-594-0259 (24 hour direct line) e-mail: [email protected] Subscription rate for 6 issues: Octave for Bessel Functions In the US: ARRL Member $24, 26 By Maynard Wright, W6PAP nonmember $36; US by First Class Mail: ARRL member $37, nonmember $49; International and Canada by Airmail: ARRL member $31, nonmember $43; Columns Members are asked to include their membership control number or a label from their QST when applying. In the Next Issue of QEX Letters In order to ensure prompt delivery, we ask that 25 37 you periodically check the address information on your mailing label. If you find any inaccura- cies, please contact the Circulation Department SDR: Simplified immediately. Thank you for your assistance. 30 By Ray Mack, W5IFS 38 Upcoming Conferences Tech Notes Copyright © 2009 by the American By Mike Hamel, WO1U and Radio Relay League Inc. For permission 2009 QEX Index to quote or reprint material from QEX 35 David Cripes, NMØS 39 or any ARRL publication, send a written request including the issue date (or book title), article, page numbers and a Index of Advertisers description of where you intend to use the reprinted material. Send the request American Radio Relay League: ....... Cover III Nemal Electronics International, Inc: ........29 to the office of the Publications Manager Down East Microwave Inc: ........................25 RF Parts .............................................37, 39 ([email protected]). ICOM ..............................................Cover IV Second Hand Radio .................................34 Kenwood Communications: ............. Cover II Tucson Amateur Packet Radio: ................17 National RF, Inc: .......................................25 QEX – July/August 2008 1 TOFC.indd 1 12/15/2009 4:23:22 PM The American Radio Larry Wolfgang, WR1B Relay League [email protected] The American Radio Relay League, Inc, is a noncommercial association of radio amateurs, organized for the promotion of interest in Amateur Radio communication and experimenta-tion, WWW.RADiOSCAMATORUL.Hi2.ROEmpirical Outlook for the establishment of networks to provide communications in the event of disasters or other emergencies, for the advancement of the radio art and of the public welfare, for the Where do we go from here? representation of the radio amateur in legislative matters, and for the maintenance of fraternalism and It’s a simple question, really, and one I’ve heard many times over the years. You prob- a high standard of conduct. ably have, too. As we reflect on the past and look to the future, it’s not unusual to wonder ARRL is an incorporated association without what that future holds. It would be nice to have a crystal ball and be able to see a year or capital stock chartered under the laws of the state two or ten years into the future. Of course for all the magic that is ham radio, that’s not part of Connecticut, and is an exempt organization under Section 501(c)(3) of the Internal Revenue of our bag of tricks. Code of 1986. Its affairs are governed by a Board of Directors, whose voting members are elected In years past I have been in a number of meetings, discussing the future of Amateur every three years by the general membership. The Radio. I remember when packet radio was the hot new topic, and there was a lot of discus- officers are elected or appointed by the Directors. The League is noncommercial, and no one who sion about building packet networks to link all Amateur Radio operators through one or could gain financially from the shaping of its another networking plan. While the days of packet bulletin boards and that initial burst of affairs is eligible for membership on its Board. activity may be waning, others have quietly gone on to build new network opportunities “Of, by, and for the radio amateur,” ARRL such as the APRS network, with its messaging opportunities and emergency communica- numbers within its ranksWWW.GiURUMELE.Hi2.RO the vast majority of active tions capabilities. Many operators use WinLink and other message forwarding techniques amateurs in the nation and has a proud history of achievement as the standard-bearer in amateur on a daily basis. affairs. Software defined radio has been a hot topic for many years now. We continue to see A bona fide interest in Amateur Radio is the only new developments and improvements in radio technology and capabilities. Most modern essential qualification of membership; an Amateur Radio license is not a prerequisite, although full transceivers make use of at least some aspects of the SDR concept. While some of the voting membership is granted only to licensed best performing radios still rely on traditional radio circuitry, they also allow new software amateurs in the US. versions to be downloaded directly to the radio, with vast new capabilities and subtle per- Membership inquiries and general corres- formance enhancements. Other high performance radios have moved toward the concept pondence should be addressed to the administrative headquarters: of direct digitization of the RF signals, with all processing done in dedicated digital signal processing ICs and personal computers. Whether you want to buy or build a high-perfor- ARRL mance radio, there are plenty of opportunities to play with SDR. 225 Main Street Newington, CT 06111 USA Another buzzword I’ve heard a number of times is “adaptive radio.” As I understand it, Telephone: 860-594-0200 FAX: 860-594-0259 (24-hour direct line) the concept is that the transceivers might be able to change their operating parameters automatically, based on band conditions and communications modes. Perhaps the radio Officers detects interference from another signal near its operating frequency. Filter bandwidth and President: JOEL HARRISON, W5ZN passband position shifts to cut out the offending signal. The radios communicate about 528 Miller Rd, Judsonia, AR 72081 received signal strength and other band conditions under the operators’ communications Chief Executive Officer: DAVID SUMNER, K1ZZ and adjust transmitter power and perhaps even digital data speeds. All of this happens without any operator intervention. Some of this may sound a little farfetched, but is it The purpose of QEX is to: really? What can we do to build more intelligence into our radios? What new features 1) provide a medium for the exchange of ideas and would you like to find on your next dream radio? information among Amateur Radio experimenters, What other changes do you see on the horizon? Will we see years of subtle changes 2) document advanced technical work in the Amateur and improvements to our current circuitry and techniques, or is there some new idea Radio field, and ready to break through and change the way we define “radio” in the future? Are there 3) support efforts to advance the state of the radical new antenna designs waiting to be discovered, or do we know all there is to learn Amateur Radio art. about antenna design? What new digital (or analog) communications techniques and All correspondence concerning QEX should be modes will be invented or evolved? What do you think? addressed to the American Radio Relay League, 225 Main Street, Newington, CT 06111 USA. QEX has published the technical details of all these past developments, and continues Envelopes containing manuscripts and letters for to help advance the state of the radio art. Whether you want to learn about the latest tech- publication in QEX should be marked Editor, QEX. niques or want to experiment and push the envelope yourself, we want to bring you the Both theoretical and practical technical articles are information you need. I am sure we will continue to have articles about packet networking welcomed. Manuscripts should be submitted in word- processor format, if possible.