Past AMRAD Meetings
May 15 - "Practical Applications for High Speed Mesh Networks" Keith Elkin, KB3TCB, demonstrated the equipment used for high speed MESH networks and backbone links. He detailed a proposal to link regional MESH networks with microwave links.
April 17 - "Fun With Electric Motors" Karl Berger, W4KRL reviewed the fundamentals of direct current motors and ran tests on a century-old open frame dc commutator motor that has slip rings connected to one rotor winding. This enabled observing the rotor voltage on an oscilloscope. All control of the motor control was done with an Arduino using Pulse Width Modulated power supplies, Hall-effect current sensors, and servo-driven instrumentation.
March 20 - "An Amateur-Radio Solution to Frequency-Hopping Synchronization" André Kesteloot N4ICK and Maitland Bottoms AA4HS jointly presented a creative approach to the spread spectrum challenge posed by André in his December 2013 presentation.
February 13 - cancelled by snow
January 9 - "Rubidium Frequency Standards and Teardown" Frank Gentges, KØBRA, briefed us on rubidium frequency standards. Then, upholding a proud AMRAD tradition, he toredown a Frequency Electronics type FE-5682A standard.
- December 12 - Annual Business Meeting. Directors elected for 2014-2015: Paul Rinaldo, W4RI, Frank Gentges, KØBRA, Karl Berger, W4KRL
André Kesteloot, N4ICK, demonstrated an Arduino-based "Spread-Spectrum Frequency-Hopping Transmitter Module" that he has developed. André needs ideas for the receiver side of the system. AMRAD members engaged in a lively discussion about how the receiver could detect and lock on to the transmitted signal.
November 21 - Bill Liles, NQ6Z “100 Years of Amateur Aerials” The Radio Society of Great Britain is 100 years old this year. For the celebration they have gone through their archives and produced a set of talks. One talk is on 100 years of amateur aerials. Bill presented this talk with photos and discussion.
October 10 - Ron Payne, WA6YOU - "Coax Connectors - The Intimidating Interface." Ron demonstrated installing PL259 and BNC coax crimp connectors and weatherproofing methods.
September 19 - Mark Braunstein, WA4KFZ, provided an overview of printed circuit board fabrication for the electronics experimenter. Mark has personal experience using CNC routers in a commercial enterprise. Other options for do-it-yourselfers include conventional photo-etching and contact etching with laser printed masks. A number of domestic and foreign fabricators offer fast turn around at low cost but with confusing choices for software and file formats.
August 8 - Maitland Bottoms, AA4HS, introduced us to digital voice communications on HF using FreeDV software. FreeDV is an application for Windows, Linux and MacOS (BSD and Android are in development) that allows any SSB radio to be used for low bit rate digital voice. The software compresses speech to 1400 bit/s then modulates a 1.1 kHz wide quadrature phase-shift keying (16-QPSK) signal which is sent to the Mic input of a SSB radio. On receive, the signal is received by the SSB radio, then demodulated and decoded by FreeDV. Communications is readable down to 2 dB S/N, and long-distance contacts are reported using 1-2 watts power.
July 18 - Dr. Frank Eliot, W3WAG, discussed Weak Signal Detection. Thanks to the rapid increase in digital processing availability, hams have implemented sophisticated and user-friendly techniques that enable us to communicate with much weaker signals than we had dreamed of exploiting just a few years ago. In this session, Frank discussed weak signal detection, exploring under what circumstances we might detect even weaker signals, thus communicating over even more difficult paths. Also, on a related topic, he described how earth antennas behave, and experiments one might perform to sort out their modes of operation.
June 13 - AMRAD hosted a doubleheader for slow modes: DFCW and JT65.
The first presentation was by André N4ICK titled An Arduino-based DFCW Beacon for the 479 KHz Band. André discussed Dual Frequency CW (DFCW) and updated us on the ARRL petition to the FCC Office of Engineering and Technology regarding the new band. He demonstrated his design of an Arduino-based 479kHz beacon, and expanded on the eventual possibility of "crossing the Pond" to communicate with British Hams who have been experimenting for a while with this new allocation.
Dual Frequency CW, or DFCW, is a technique where a CW signal is transmitted at a very slow symbol rate, typically at 3 seconds per dot. This allows reception in very narrow bandwidths.
Terry McCarty, WA5NTI, made a presentation on The JT65 Weak Signal Digital Soundcard Mode. JT65 can decode signals many decibels below the noise floor making an exception to the old rule “if you can’t hear them, you can’t work them.” Terry has racked up an impressive list of contacts on nearly every band. The mode was developed by Joe Taylor, K1JT as an offshoot to his WSJT weak signal mode widely used in moonbounce contacts. Although JT65 was originally intended for troposcatter and Earth-Moon-Earth paths, Terry is one of the pioneers in using it for low power HF contacts. Terry told us where to get the free software, how to configure it, and what you can expect in a contact.
May 9 - Karl Berger, W4KRL, shared his adventure exploring the possibilities for using the Arduino microcontroller in amateur radio projects. Karl set out a few months ago to make a stand-alone touch screen display for a portable antenna analyzer. He broadened his objective to include a flexible graphic display system that a ham can adapt to station control, test instruments and data logging. Along the way, he overcame challenges in converting his program from “in line” coding to the “object oriented” style and solving unexpected problems with hardware control.
April 11 - Ron Payne, WA6YOU, demonstrated how to build UHF Yagi antennas for receiving off-air DTV stations, or, for any UHF band application. Ron demonstrated his method of building antennas using spun copper wire for the antenna elements and how to get great results with low cost construction.
March - Andrea Hartlage, KG4IUM, "Involving Youth in Ham Radio and A Look Inside the ARRL Board Room"
February - Paul Mooney, K4KRE,"An Experimental SDR Project"
January - Jim Veatch, WA3EUJ,"ARRL Homebrew Challenges"
December - Annual Business meeting.
November - Andre Kesteloot, N4ICK, "A 40-Meter Class E Rig", and George Lemaster, WB5OYP, "Non-Linear Effects"
October - Presentation by Terry Fox, WB4JFI
September - John Donaldson, AB8YZ,"Applications of HSMM-MESH"
August - Bob Sullivan, W0YVA,"Boat Anchor Restoration"
July - TBD
June - Sir Richard O’Neill, Wizard3 (a.k.a. KBRSJ),"How to Make a Crystal Set"
May - Kevin Whipp, W3KDW, David Bern, W2LNX and Vic Nardo, WB2U,"HSMM-MESH"
April 19 - ARRL Chief Technology Officer Brennan Price, N4QX, reviewed the ITU 2012 World Radiocommunication Conference and the outlook for a new domestic allocation at 472-479 kHz.
March 8 - Terry McCarty, WA5NTI, told us how he automated his ham station with a PC to make working, logging, and QSLing DX stations easy.
February 16 - Jerry Wolczanski, KI4IO, described the high performance Low Frequency (LF) receiver he designed and built as well as his vintage German Torn E.b regenerative LF receiver. Jerry has logged many LF Non Directional Beacons (NDBs) with a very interesting LF antenna he designed.
January - Greg LeSAge, N6LYU, "The Terminated Folded Dipole (T2FD) Antenna"
December - AMRAD's Annual Meeting. Elections were held at the meeting. Directors Bill Fenn, N4TS; Frank Gentges, KØBRA; and Paul Rinaldo, W4RI were re-elected for two-year terms, as were Alternates Paul Mooney, K4KRE and Rob Seastrom, AI4UC for one-year terms
November 10 - Dr. Michael King, an experienced high-performance HF receiver designer, spoke on hardware design for Software Defined Radio systems that hams can build.
October 13 - This meeting was devoted to a discussion of digital amateur television by Bill Fenn, N4TS and Paul Rinaldo, W4RI. DVB-S and other protocols were covered.
September 8 - This meeting was affected by the heavy rain which caused many people and the speaker to be caught in traffic. See rescheduled meetings for October and November.
August 11 - The August meeting was CANCELLED.
July 14 - This meeting was a preparation for our Manassas special event of 21-24 July jointly with the Ole Virginia Hams.
June 9 - Chris Paton, W3CUM talked about Skywarn.
May 12 - Terry Fox, WB4JFI, talked to us via Skype about current and developing projects. He provided detail about modular programming of FPGAs. Terry provides an article in the July-August AMRAD Newsletter.
April 14 - George Lemaster, WB5OYP presented a visual tour of the Bletchley Park National Codes and Cipher Centre.
March 10 - Greg LeSage, N6LYU, spoke on his Beverage antenna system.
February 10 - Mike Toia, K3MT, talked on antenna modeling and theory.
January 13 - Frank Gentges, KØBRA, made a presentation on the latest do-it-yourself surface-mount techniques.
- December 14 - The Annual Meeting gave an opportunity for members to report on progress of projects and to elect new Directors and Alternates. Results of the election are: Directors (11-12): Terry Fox, WB4JFI George Lemaster, WB5OYP Alternates (11) Paul Mooney, K4KRE Rob Seastrom, AI4UC
The meeting accepted a proposal by Bill Fenn, W4TS, to commemorate the anniversary of the First Battle of Manassas with a special event station.
November 10 - This meeting was a briefing by Doug Lindsey, KB3HER, on SHARES, MARS and emergency communications.
October 14 - Terry Fox, WB4JFI, made an audio/video presentation via Skype about his software defined radio developments. He also did a scan of his shack. This was a first AMRAD use of Skype and we hope to do more.
September 9 - Dr Andrew Clegg, W4JE, presented a show-and-tell of the Perseus software-defined receiver (http://www.microtelecom.it/perseus/).
August 28-29, AMRAD field trip to the National Radio Astronomy Observatory (NRAO), Green Bank, WV Twenty-five AMRADers participated in the field trip. Look for the photos in the Nov-Dec 2010 issue of the AMRAD Newsletter.
March 11 - Steve Stearns, K6OIK, gave an extensive report on antenna matching at multiple frequencies simultaneously and broadband match along with Smith chart tricks.
February 11 - cancelled by snow.
January 14 Greg Le Sage, N6LYU, briefed us on his work on high efficiency antenna tuners. The meeting was held at the Falls Church Community Center, 223 Little Falls St., Falls Church, VA.
December 10 - This was our Annual Meeting for an exchange between members and Board Members on activities. In addition, there was an update on spectrum management issues of importance to hams.
September 10 - This was a discussion of progress with construction of the Charleston software defined radio receiver, led by Frank Gentes, KØBRA.
August 13 - Dr Joe White of the Naval Research Laboratory described his work with precision clocks. The Naval Research Laboratory and the Naval Observatory have set up a clock comparison system using the WTTG (channel 5) digital television signal. This talk discussed time and frequency comparison using television signals.
July 9 - Bill Fenn, N4TS, talked about the transition to Digital Television and described the ATSC digital television transmission format. Bill demonstrated how to dissect an off-air transport signal using a Tektronix analyzer.
June 18 - Hal Feinstein, WB3KDU, made a presentation on optical fiber communications.
April 9- Greg LeSage, N6LYU returned to talk about lasers. Topics were chirped pulse amplification, photoemission, and laser scattering from relativistic charged particle beams.
March 12 - Greg LeSage, N6LYU spoke on RF powered particle accelerators, how and why large RF systems are engineered for these massive machines. Greg showed a number of components used.
February 12 - This included a video presentation of W1FR's talk. This was an experiment, which proved successful. The AMRAD Board of Directors decided to purchase the video camera used for this demonstratin, so it will be available for future meetings.
February 11 - Dr Frederick Raab, W1FR briefed us on the "500 kc experiment." See article in the Mar-Apr edition of the AMRAD Newsletter.
January 8 - Rob Seastrom, AI4UC and Maitland Bottoms, AA4HS presented a tutorial on posting to the AMRAD Wiki Web site.