The American Radio Relay League

The American Radio Relay League, Inc, is a noncommercial association of radio amateurs, organized for the promotion of interests in Amateur Radio communication and experimentation, tor the establishment of networks to provide communications in the event of disasters or other emergencies, for the advancement of radio art and of the public welfare, for the representation of the radio amateur in legislative matters, and for the maintenance of fraternalism and a high standard of conduct.

ARRL is an incorporated association without capital stock chartered under the laws of the state of Connecticut, and is an exempt organization under Section 501(c)(3) of the Internal Revenue Code of 1986. Its affairs are governed by a Board of Directors, whose voting members are elected every two years by the general membership. The officers are elected or appointed by the Directors. The League is noncommercial, and no one who could gain financially from the shaping of its affairs is eligible for membership on its Board.

"Of, by, and for the radio amateur, "ARRL numbers within its ranks the vast majority of active amateurs in the nation and has a proud history of achievement as the standard-bearer in amateur affairs.

A bona fide interest in Amateur Radio is the only essential qualification of membership; an Amateur Radio license is not a prerequisite, although full voting membership is granted only to licensed amateurs in the US.

Membership inquiries and general correspondence should be addressed to the administrative headquarters at 225 Main Street, Newington, CT 06111 USA.

Telephone: 860-594-0200

Telex: 650215-5052 MCI

MCIMAIL. (electronic mail system) ID: 215-5052

FAX: 860-594-0259 (24-hour direct line)

Officers

President: RODNEY STAFFORD, KB6ZV

5155 Shadow Estates, San Jose, CA 95135

Executive Vice President: DAVID SUMNER, K1ZZ

Purpose of QEX:

1) provide a medium for the exchange of ideas and information between Amateur Radio experimenters

2) document advanced technical work in the Amateur Radio field

3) support efforts to advance the state of the Amateur Radio art

All correspondence concerning QEX should be addressed to the American Radio Relay League, 225 Main Street, Newington. CT 06111 USA Envelopes containing manuscripts and correspondence for publication in QEX should be marked: Editor, QEX.

Both theoretical and practical technical articles are welcomed. Manuscripts should be typed and doubled spaced. Please use the standard ARRL abbreviations found in recent editions of The ARRL Handbook. Photos should be glossy, black and white positive prints of good definition and contrast, and should be the same size or larger than the size that is to appear in QEX.

Any opinions expressed in QEX are those of the authors, not necessarily those of the editor or the League. While we attempt to ensure that all articles are technically valid, authors are expected to defend their own material. Products mentioned in the text are included for your information; no endorsement is implied. The information is believed to be correct, but readers are cautioned to verify availability of the product before sending money to the vendor.

Empirically Speaking

Here is the first bimonthly issue of QEX, and we are even pretty close to being on time. As you can see, we have filled 64 pages, and we hope to keep it that way in the future. I would like to pass my special thanks to Bob Schetgen, KU7G, and Joe Shea for pumping through twice the material we usually do in a month.

Last month I mentioned the class-E kit from Nat Sokal, and just after we went to print Dave Rutledge sent me note about the kit his gang is providing. They are the authors of the QST articles (May/June 1997) and have been making an inexpensive kit available for the amplifier. They are basically selling it at cost. Being good techies, they have a Web site at: http://www.systems.caltech.edu/ EE/Faculty/rutledge/puff.html. We talked a little bit about the power supply (not included in the kit!), which was quite conventional in the article. What we need is a nice switch-mode power supply to go along with the switching amplifier. Any volunteers out there? I'm going to put together one of the kits and design a switcher for it as soon as I get caught up with QEX. That should be some time in the 23rd century!

As you can tell from the contents of this issue, we are beginning to broaden our technical coverage, but we still have many subjects to add. How about QRP? I know there are hotbeds of homebrewing out there, why not share some of your ideas with us? I, like many other amateurs, have been looking for operating challenges beyond the usual HF DXing on 80 through 10 meters: at the low end is 160 meters and at the high end 6 meters. Each of these bands poses a significant and often very frustrating challenge for long-range communication. On the top-band reflector (e-mail [email protected]) I have seen a steady flow of propagation, antenna, tuner and preamplifier discussion. I am sure this only the tip of the iceberg. QEX could use some of these ideas. How about 6 meters? As we swing up on the sunspot cycle, long-range DXing on 6 meters will become possible more frequently. I am sure many of you are thinking and plotting to take advantage of this. QEX is a great place to talk through the propagation and antenna issues.

This Month in QEX

Have you ever wondered how the placement of your 2 meter mobile whip affects the radiation pattern? Peter Madle, KE6RBV, has modeled his 1987 Ford Taurus with a 2 meter mobile antenna at various locations using EZNEC. He shows us just how far from omnidirectional the pattern can be. That QSB while in motion isnit all due to the changing scenery.

Paul Wade, N1BWT, a frequent QEX contributor, analyzes parabolic dish feeds. He presents plots to help you choose a feed for your dish, based on performance. His FEEDPATT program lets you model the systems.

RF phase-shift networks are the backbone of phasing-SSB rigs and direct-conversion receivers. Byron Blanchard, N1EKV, takes us on a guided tour of phasing networks. Learn about their performance and their limitations.

Do you want to monitor Phase-3D on 2.4 GHz? John Reed, W6IOJ, shows us how to build a 2.4 GHz receiver using commonplace components usually only considered for UHF work. Again, the emphasis is on using low-cost and readily available components.

Have you been thinking about a homebrew high-power amplifier but wondering where to get an economical power supply? Randy Henderson, WI5W, shows you how to use transformers and other parts from defunct microwave ovens, which may be free for the asking. This is in the tradition of the amateur scrounger who uses widely available and often discarded components to build a rig.

Zack Lau, W1VT, presents a portable 6 meter beam in his RF column. (That's it on the cover.) With the change to a bimonthly QEX, Zack's popular column is scheduled for every issue.—73, Rudy Severns, N6LF, [email protected]

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