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, for 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, CT06111 USA.

Telephone: 203-666-1541

Telex 650215-5052 MCI

MCIMAIL (electronic mail system) ID: 215-5052

FAX: 203-665-7531 (24-hour direct line)



1649 Griffith Ave, Owensboro, KY 42301

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

Overseas QEX for Less

For some time we've been hearing from our friends outside North America that, while they enjoy reading QEX, they distinctly don't enjoy paying $48 or $60 per year for the privilege of doing so. Those rates, for members and nonmembers, respectively, aren't intended to gouge our offshore readers. Rather, they reflect the high cost of getting QEX—or any magazine—mailed for timely delivery from the US to other continents via air mail.

What many have told us, particularly in Europe, is that they would happily opt for slower delivery if we could bring the subscription price down substantially. At the same time, there are still those readers who want their QEX right away, despite the cost. So, we've decided to let the reader make the decision. Beginning immediately, new and renewal subscribers to QEX from outside North America can opt to have their copy delivered by surface mail, at an annual cost of $20 for ARRL members and $32 for nonmembers. This is a substantial savings over the airmail rates. But for those in a hurry, the airmail rates—and the consequent fast delivery—are still available.

Of course, those who do opt for the surface rates have to understand that surface mail is slow. If you subscribe to QEX at the lower rate, don't be surprised if your copy takes 1 to 2 months to reach you. You can have it fast or you can have it cheap, but we've not found a way to give it to you fast and cheap.

More on HF Simulators

Last month in this space we noted the activity on the TAPR HF-SIG mailing list, which is discussing the possibility of developing a DSP-based HF channel simulator to use to test modem designs and implementations. We're happy to say that the work is progressing. Those participating are rapidly finding the relevant published material, including CCIR Recommendations, papers in the professional literature and books that address the subject of how to implement channel simulation.

While it's still a bit early—no code has been written yet, as far as we know—it is becoming clear that the problem is a tractable one for the cur rent generation of low-cost DSP hardware available to hams. We have little doubt that the next few months will see an HF channel simulator implemented and running.

One of the lessons we are all re-learning from this effort is that putting multiple minds on a project can make it easier, and that effective digital communications—via the Internet, in this case—makes the meeting of minds easier to achieve. Now if only we could carry out these discussions via an amateur digital network. Sigh.

This Month in QEX

It's one thing to build a home-brew receiver or transmitter. It's another to know how it stacks up performance-wise. "The MTG1 Multitone Test Generator," by Detlef Rohde, DL7IY, provides audio and 80-meter two-tone signals and an HF comb generator, all of which can help you test your latest creation.

How well do these modern HF digital modes really work? A partial answer is provided this month by Peter Reynolds, KE4BAD, who reports on some "HF Channel Simulator Tests of Clover."

Been "Hearing Strange UHF Signals Lately?" If so, maybe your 70-cm preamp can't handle the high levels of commercial signals in nearby bands. John Reed, W6IOJ, provides an integrated preamp and filter design that may help.

There is much confusion among amateurs as to where the reflected power on a transmission line ends up. The answer is: in the load. But why? This month, your editor, Jon Bloom, KE3Z, takes his shot at explaining "Where Does the Power Go?"

In this issue, Ladimer S. Nagurney, WA3EEC, contributes a review of the book: Digital Signal Processing in Communication Systems, by Marvin E. Frerking. Does the book tell you how to generate and process modulated signals with DSP? Read the review!

This month's "Proceedings" column lists the papers in the Proceedings of the AMSAT-NA 12th Space Symposium and AMSAT Annual Meeting.

Finally, in his "Digital Communications" column this month, Harold Price, NK6K, reports the interesting reactions of several readers to his recent gloom-and-doom columns about packet.—KE3Z, email: [email protected] (Internet)

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