The November/December issue of QEX is coming soon, and it is full of theoretical and practical technical articles that you don't want to miss.

In this issue, Jim Koehler, VE5FP, describes "A DDS-Based Signal Generator." Based on the NimbleSig III direct digital synthesizer described by Tom Alldread, VA7TA, that appeared in issues of QEX earlier this year, Koehler has created a laboratory grade test instrument with features most home builders would want. Horst Steder, DJ6EV, and Jack Hardcastle, G3JIR, describe their computer program to design "Crystal Ladder Filters for All." In this article, the authors describe the design and crystal selection process and lead us through the use of their program to design crystal ladder filters. The program is available on the Downloadable Files section of the QEX Web site.

Rudy Severns, N6LF, presents the next stage of his research in "Experimental Determination of Ground System Performance for HF Verticals." Part 6 focuses on ground radial systems for multiband vertical antennas. Victor Kean, Jr, K1LT, presents a way to use a phased array of four shortened vertical antennas for the "top band" in "Beam Steering on 160 Meters." His system uses four Softrock software defined radio modules to create the phasing needed to steer the array in any direction.

Paul Wade, W1GHZ, begins a series on "Waveguide Filters You Can Build and Tune" with "Part 1 -- A Tour of Filters." UHF and Microwave enthusiasts won't want to miss this series! And Ray Mack, W5IFS, continues his software defined radio column: In this installment of "SDR: Simplified," Ray teaches us about "Sampling, Nyquist and Spectrum." He also gives us more detail about Discrete Fourier Transforms.

QEX is edited by Larry Wolfgang, WR1B, and is published bimonthly. The subscription rate (6 issues) for ARRL members in the US is $24. For First Class US delivery, it's $37; in Canada and internationally by airmail it's $31. Nonmembers add $12 to these rates. Subscribe to QEX today. Would you like to write for QEX? It pays $50/printed page. Get more information and an Author's Guide here. If you prefer postal mail, send a business-size self-addressed, stamped envelope to QEX Author's Guide, c/o Maty Weinberg, ARRL, 225 Main St, Newington, CT 06111-1494.