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 860-594-0200

Telex: 650215-5052 MCI

MCIMAIL (electronic mail system) ID: 215-5052

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



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 arid contrast, and should be the same size or larger than the size that is to appear in QEX.

Any opinions expressed in QEX ate 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

Device Data via the Web

A collection of dog-eared semiconductor device-data books can be found scattered around most experimenters* shacks. And unless you work in a commercial electronics lab, you probably use data books that are at least a couple of years out of date. Even if you do have the latest books, what about the reams of update sheets that come out between printings of any data book? There is a solution to this problem, and it will come as no surprise to you that the solution is the World Wide Web.

Most of the companies that produce semiconductor devices make at least some data available for access on the Web. Often, the available data is surprisingly complete. And sometimes there is more data available electronically than there is in the data book! Here's a list of sources of device data on the Web. It's necessarily an incomplete list, but it covers many of the major manufacturers. Note that many of these sites provide the data in the form of Adobe PDF files. You'll need the (free) Adobe Acrobat reader to view the data; the sites that serve PDF files also provide instructions for obtaining Acrobat. These sites are almost all under continual development, so we won't go into specifics as to what's available at each site. We've tried to start you at the page on each site that gets you to the product information fastest. Analog Devices: Cirrus Logic/Crystal Semiconductor: prodtech/ Exar: prodques.htm

Harris: product_information.html

Hitachi: tech/tech.html

Maxim: Motorola: National Semiconductor: NEC:




Siemens: Texas Instruments: schome.htm Xilinx: products.htm

Zilog: products.html

Other links to manufacturer product pages are available at http://www and_Economy/Companies/Semi-conductors/.

This Month in QEX

Any receiver or transmitter project requires a stable signal source for the receiver LO or the transmitter carrier oscillator. At VHF and UHF, making a stable tunable signal source is most easily done using frequency synthesis. And if you're a VHF/UHF enthusiast, a synthesizer circuit capable of generating a wide range of frequencies would be ideal. Stuart Rumley, KI6QP, presents just that in "The KI6QP Dual Synthesizer Module." His design has both VHF and UHF outputs and operates from 50-2000 MHz or, by mixing the two outputs, up to 2500 MHz.

Among those projects we've published in the past few years, few have sparked more interest than the (almost) all-digital receiver based on a digital down converter. This month, Peter Traneus Anderson, KC1HR, extends the design by adding "A Simple CW Transmit VFO for the DDC-Based Receiver." Using the VFO to drive a high-tech transmitter (a Heath DX-40!), Peter has achieved transceive operation—controlled by a PC.

If you want to design a passive network to match two known impedances, you'll find all of the theory and cookbook solutions easily. But what if you want to know the range of impedances a particular network will match? That's quite a bit different! In this month's "RF" column, Zack Lau, KH6CP/1, shows some computer-aided techniques for finding the answers —KE3Z, email: [email protected].

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