Upcoming Meetings
February 12, 2015, 7:30pm NOTE: This meeting is in Tysons Pimmit Library! - Brennan T. Price, N4QX, is ARRL’s Chief Technology Officer, and represents the interests of Amateur Radio to numerous governmental and international agencies, including the FCC, NTIA, and ITU. With the staff of ARRL’s Technical Relations Office and ARRL’s Washington Team, he prepares for World Radiocommunications Conferences, held about once every four years, at which spectrum is internationally allocated to various radio services.
Tysons Pimmit Library http://www.fairfaxcounty.gov/library/branches/ty/
7584 Leesburg Pike, Falls Church, VA 22043March 12, 2015, 7:30pm NOTE: This meeting is in Tysons Pimmit Library! - Frank Gentges, KØBRA will demonstrate an infrared (IR) thermal imaging camera attachement for smartphones.
Tysons Pimmit Library http://www.fairfaxcounty.gov/library/branches/ty/
7584 Leesburg Pike, Falls Church, VA 22043
Recent Meetings
January 8 - John Huggins, KX4O "The J-Pole Antenna: Myths and Facts." John modeled a 1/4-wavelength ground plane as a reference and then compared several J-pole configurations using a combination of Numerical Electromagnetics Code (NEC) and Finite-Difference Time-Domain method (FDTD) antenna modeling software. Simulation results were confirmed with 1GHz models in a test chamber. He discussed the radiation patterns and antenna currents in each variant. John brought several J-pole antennas to the meeting to show off various construction techniques.
December 10 - George Lemaster, WB5OYP and Terry McCarty, WA5NTI were re-elected as Directors. Bill Fenn, N4TS and Frank Eliot, W3WAG were elected as Alternates. Terry WA5NTI made a presentation of the terminal equipment being deployed on a high speed MESH network in Prince William County. Paul W4RI was presented with an engraved wood plaque in recognition of his election to the grade of President Emeritus.
November 12 - Karl Berger, W4KRL, presented lessons learned while building and enhancing an Arduino-based Morse Decoder using the Goertzel algorithm for tone detection. He reviewed useful design tools including IdealCircuit for filter simulation and VeroDes for laying out a stripboard.
Upcoming Events
January 25, 2015 | Post Holiday Hamfest Location: Odenton, MD Sponsor: Maryland Mobileers Amateur Radio Club Website: https://sites.google.com/site/marylandmobileers/hamfests-1/hamfest-2
February 7, 2015 | Frostfest Location: Richmond Raceway Complex http://www.frostfest.com
March 22, 2015 | Vienna Wireless Winterfest Location: Northern Virginia Community College Annandale Campus 8333 Little River Turnpike Annandale, Virginia http://www.viennawireless.org/winterfest.php
June 21, 2015 | BARC Father's Day Hamfest Location: Upperco, MD Sponsor: Baltimore Amateur Radio Club Website: http://www.gbhc.org
Newsletter Articles
The articles written by AMRAD members for the Newsletter cover a wide range of theoretical and practical topics in amateur radio technology. The current Newsletter is mailed to all members. Selected articles of widespread interest to the amateur radio community are freely available here: Featured Articles
Project Proposal - Weak Signal Detection
Frank Eliot W3WAG proposes development of an innovative weak signal mode. AMRAD members and others are asked to comment on and expand his concept described in this paper: Weak Signal Paper 2014.11.10.pdf
Pete KA3WCA ran some simulations, suggests a simplification to the receiver algorithm, and describes "Transmitted Reference" modulation schemes to reduce the effects of channel phase variations. WeakSignal KA3WCA 2014-11-20.pdf
KA3WCA further develops the math to correlate two different phases of the carrier and provides Python code to evaluate the correlation and phase angle. WeakSignal KA3WCA TwoPhaseCorrelation 2014-12-01.pdf