The July/August issue of QEX is out, and it is full of theoretical and practical technical articles that you don't want to miss.

In this issue, John Post, KA5GSQ, describes a crystal controlled 145 MHz oscillator in "VHF Frequency Multiplication Using the SA602 IC." Wes Hayward, W7ZOI, returns to the pages of QEX with an article about "Oscillator Noise Evaluation with a Crystal Notch Filter." James Koehler, VE5FP, shares "Some Thoughts on Crystal Parameter Measurements" as he describes an automated system he built using a new DDS signal generator and microcontroller circuit to make the measurements and perform calculations.

Al Christman, K3LC, expands on the investigations in his July/August 2005 QEX article with "Ground System Configurations for Phased Vertical Arrays." Contributing Editor L.B. Cebik, W4RNL (SK) looks at the characteristics of one wavelength loops in "Antenna Options," and Ulrich Rohde, N1UL, takes us on a tour of early RF oscillators in "From Spark Generators to Modern VHF/UHF/SHF Voltage Controlled Oscillators."

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QEX is edited by Larry Wolfgang, WR1B, and is published six times a year. The subscription rate for ARRL members in the US is $24. For First Class US delivery, the rate is $37 for members, $49 for nonmembers. For international delivery via air mail, including Canada, the subscription rate is $31 for members, $43 for nonmembers. Subscribe to QEX today.