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Here are a some still-relevant presentations (of at least a dozen or so) that have been made at Ham Conferences and magazines.

 

HF Ionospheric Simulation. Discusses ionospheric phenomenon and effects on HF signals, and method to simulate. Presentation made at the ARRL/TAPR Digital Communications Conference, 1996. (PDF)

 

Modeling Eye Patterns using Excel. Discusses how to simulate the eye pattern based on the channel response using Microsoft Excel 5.0. Presented at the TAPR Digital Communications Conference 1995. (PDF)

 

Low-cost 100 MHz Vector Network Analyzer with USB interface, as printed in the July / August 2004 issue of QEX. This is a project that Karl Ireland and I worked on for about 2 years. TAPR went through a beta test. Due to the use of several fine-pitch SMT IC’s, a kit turned out to be impractical. TAPR licensed the unit to TenTec, who manufactures and sells a completed & tested unit.

 

Brief SDR presentation focusing on Softrock40 that Van Sias, K7VS demonstrated at the RVARC club meeting on October 2, 2008.

 

Antenna Modeling presentation on the basics on modeling antennas with NEC-2 software and related interface programs. Presented at the RVARC club meeting on March 4, 2009. 

 

Soundcards for Amateur Radio Presented at the RVARC club meeting on October 1, 2009.

· Background on soundcards — block diagram, drivers, controls, color codes, etc.

· Applications

· Sounds, recording, playback, editing.

· Amateur digital modes.

· Test Equipment.

· Software Define Radio.

· Some interfacing tips to HF transceivers.

· Performance requirements for baseband audio and SDR applications.

 

Smith Charts & Impedance Matching Presented at the RVARC club meeting on April 1, 2010.

· Simplified, common-sense description of the Smith Chart.

· How to impedance match a load using the Smith Chart.

· 3 examples of a mobile antenna.

 

HF Propagation (and a little NVIS) Presented at the Jackson County ARES meeting on August 18, 2010, and the RVARC meeting on September 2, 2010.

· Basics of ionization, the ionosphere

· Ionograms

· NVIS considerations, antenna considerations

 

The Care & Feeding of Simple, Broadband HF Antennas. Presented at the RVARC club meeting on March 3, 2011.

· Antenna SWR vs. frequency.

· Feedline loss vs. SWR.

· Feedline loss vs. frequency for doublet and loop antennas.

· Antenna patterns vs. frequency.

 

A Flexible 2-Port Network Calculator Tool, as printed in the May/June 2011 issue of QEX. This tool is a graphical calculator that allows constructing a network of 2-ports and computing the chained response. The basic calculation engine uses the ABCD matrix chaining method. Examples include: coax-stub filters, compensation of fixture effects, and input impedance of coupled antennas showing the effect of self and mutual element impedances.

 

Gnuradio Companion module for open HPSDR Hermes / Metis software defined radio, as printed in the Proceedings of the ARRL / TAPR Digital Communications Conference 2013 (Seattle), and slides presented at the conference.