Date: Thursday, May 19, 2016
Time: 5:00 PM Socialize, 6:00 PM Dinner, 7:00 PM Meeting starts
Location: Holder's Country Inn; 998 S. De Anza Boulevard; San Jose, CA 95129
Phone: (408) 244-2798
Program: "PureSignal ‐ Linearizing Your Amplifier with Software"
by Warren Pratt, NRØV
Over the past several decades, amateur radio receiver performance has improved significantly; however, transmitter performance in terms of spurious outputs, specifically IMD (Inter‐Modulation Distortion), has degraded. Transmitters such as the venerable Collins 32S‐3, introduced c. 1962, are measured to have superior IMD performance compared to today's transceivers using MOSFET amplifiers. IMD, a form of "splatter," is often the limiting factor in our ability to successfully make contacts today. Accumulated IMD from multiple stations significantly raises the noise and interference levels on our bands. As a result, there is a growing interest in the amateur community in improving transmitted signal purity and cleaning up the ham bands. Warren will present a technique to dramatically reduce IMD. This technique was designed for Direct‐Sampling Software‐Defined‐Radios as part of the openHPSDR program. The software solution is open source and is integrated into the software console for the Apache Labs series of ANAN transceivers. He will cover the basics of DS‐SDRs, explain the source of IMD, describe the solution to reduce IMD, and show examples and results from a few of the hundreds or thousands of amateurs now using this technology. Warren was awarded the 2014 ARRL Technical Innovation Award for his research and development in this area.
Note: Meeting will also be broadcast online via Webex. Logon as follows:
Thursday, May 19, 2016
6:30 PM PST
Join WebEx meeting
Meeting number: 802 799 450
Meeting password: dxcc
Join by phone
Access code: 802 799 450