The May/June issue of QEX will be showing up in subscriber mailboxes soon. Here's what they have to look forward to . . .

·       Steven J. Franke, K9AN, and Joseph H. Taylor, K1JT, share an under-the-hood description of the JT65 decoding procedure, and include a new algorithm for its powerful error-correcting code.

·       Ron Berry, WB3LHD, shows how he converted the classic Heathkit SB 1000 HF amplifier into a 6-meter work horse.

·       Bill Echols, NI5F, extends the definition of Maidenhead grid locators from the currently defined 8 characters to 16 characters, thus improving location precision to inches.

·       Glenn E. Elmore, N6GN, measures 10 meter propagation attenuation using a quadcopter.

·       George R. Steber, WB9LVI, uses a wide-band noise generator as an alternative to a tracking generator to measure filters and other components with a spectrum analyzer, and compares the two methods showing several examples.

·       Ray Mack, W5IFS, Demystifies proportional-integral-differential (PID) control loops and gives insights into how to build and tune one.

QEX is edited by Kazimierz “Kai” Siwiak, KE4PT, (ksiwiak@arrl.org) and is published bimonthly. QEX is a forum for the free exchange of ideas among communications experimenters. The content is driven by you, the reader and prospective author. The subscription rate (6 issues per year) for ARRL members in the United States is $24. First Class delivery in the US is available at an annual rate of $37. For international subscribers, including those in Canada and Mexico, QEX can be delivered by airmail for $31 annually. Non-members must add $12 to all rates. Subscribe today at www.arrl.org/qex.

Would you like to write for QEX? We pay $50 per published page. Get more information and an Author Guide at www.arrl.org/qex-author-guide. If you prefer postal mail, send a business-size self-addressed, stamped (US postage) envelope to: QEX Author Guide, c/o Maty Weinberg, ARRL, 225 Main St, Newington, CT 06111.