More ham radio on Twitter and G+

February 15, 2012 By Leave a Comment

Three more things I found while Twittering and using Google+.

Stay Connected to Your Broadband – an Improved ADSL Filter. I have a DSL line here, and have never had any RFI problems. In Great Britain, however, their broadband lines  seem to be susceptible. This 2010 article shows you how to build a filter that will fix that right up.

Learn circuits and electronics from MIT. The Massachusetts Institute of Technology is putting a lot of courses online, and you can take them for free!  This course, Circuits and Electronics, is the core course for all undergraduate electrical engineering (EE) and electrical engineering and computer science (EECS) students. Before you jump into this, realize that they say it will require about ten hours per week, and you need to know some basic calculus and linear algebra. This is an academic class, after all.

Open Hardware Journal. From the first page:

Open Hardware means sharing the design of physical or electronic objects with the public, similarly to Open Source software. The right to use, modify, redistribute, and manufacture, commercially or as a non-profit, is granted to everyone without any royalty or fee. Thus, Open Hardware designers hope to enrich society by developing a library of designs for useful objects that everyone can make, use, and improve.

The second issue features an article on the TAPR’s High-Performance Software-Defined Radio (HPSDR) project, which now includes over a dozen building blocks that can be used to assemble a high-grade 100 kHz to 55 MHz software-defined radio.

Filed Under: Electronics Theory, EMI/RFI, Everything Else, Software-Defined Radio

Friday at Dayton Was Forum Day

May 16, 2010 By 3 Comments
  • Friday at Dayton was “forum day.” By that I mean that I attended a slew of forums and could have attended several more. That left little time to actually scour the flea market or visit vendor booths.

    I started out in the TAPR forum, but only spent a couple of minutes there. I quickly switched over to the ARRL Public Relations forum. There I got to meet Diana Eng (see previous post). I also:

  • learned about the PR resources on the new ARRL website,
  • received a “Talk on a Disk” CD that includes materials to help you prepare a presentation on ham radio for non-technical groups, and
  • received free materials from Gordon West, including an instructor’s guide for both Tech and General classes, and CD-ROMS with a number audio clips on a variety of topics.

    • En route to the Teacher’s Forum, I passed by the Antenna Forum, which looked to be very popular. There were guys standing out in the hallway trying to hear the presentation.

    The Teacher’s Forum has been moderated by Carole Perry, WB2MGP, for as long as I can remember. She always has good speakers. This year, the lineup included Gordon West and Bob Heil.

    One idea that I picked up is to use a flashing light or LED to demonstrate the idea of duty cycle. By hooking it up to a variable duty cycle oscillator, you could vary the amount of on time versus the amount of off time, and this would make a very good visual demonstration.

    This year’s presenters mostly talked about teaching kids. This fall, I plan to teach a class for seniors. If it goes well, I’m thinking that I could talk about that class at next year’s teacher forum.

    In the afternoon, I attended the Software-Defined Radio Forum. This forum was also packed. We first heard about the new FlexRadio 1500, which is a $650 SDR. Its output is only 5W, but this looks like a real bargain.

    Next up was Lyle, KK7P, from Elecraft. He gave us the Elecraft perspective on what an SDR is and what it’s not. It was interesting, but not very technical.

    After Lyle, the TAPR VP (whose name and call I forget) talked about developments with the SDR projects at TAPR. My initial impression is that while all of these developments are well-done, it’s still much less expensive to simply buy a Flex 1500. I haven’t checked the specs, though, to see if they are comparable.

    Finally, there was a talk on MacHPSDR, a native Mac implementation of a receiver for OpenHPSDR hardware. I wish that I’d been able to stay, as I am a Mac person, but I had to leave. Despite the availability of this software, you really do need to have a PC to run a software-defined radio. I don’t expect this to change in the near future.

    Well, that was certainly enough for one day. On Saturday, there were some equally interesting forums, including forums on RTTY, SSTV, antenna-modeling software, and the AMSAT forum. Despite this, I decided to not attend a single one and walk the fleamarket and visit vendor booths. More about that in the next post.

    Filed Under: Classes/Testing/Licensing, Promotion & PR, Software-Defined Radio Tagged With: , ,

    Digital Radio Kit Covers 75-150 MHz

    October 6, 2008 By Leave a Comment

    At $1,600, this kit is a little on the expensive side for most amateurs, but it’s an interesting indication of where things are going….Dan

    Colorado Electronic Product Design, Inc. Introduces New Digital Radio Kit

    Boulder, Colorado – August 29, 2008 –

    Colorado Electronic Product Design (CEPD) introduces a digital radio kit consisting of three configurable printed circuit boards.

    The Digital Radio Kit (DRK) is intended to aid in the development and test of algorithms and signal processing applications including:

    • Digital radio, modulator/demodulator development
    • Software defined radio
    • High speed data acquisition and signal processing
    • Audio data acquisition and signal processing

    The system combines a PCI card, an FPGA signal processing card, and a down converting digital radio card. All three cards have connectors allowing them to stack, forming a digital radio system. The kit will operate in standalone mode or the PCI card can be attached to a computer.

    The standard configuration for the digital radio card is the 75MHz to 150MHz band. The digital radio card is capable of transmitting and receiving RF signals. Filters, Low Noise Amplifiers, and mixers are socket-ed to simplify frequency changes. The card includes a frequency synthesizer LO and mixers for up and down conversion for transmitting and receiving. The card utilizes a 13-bit, 210 million samples per second (MSPS) analog-to-digital converter (ADC), a 14-bit, 400 MSPS digital-to-analog converter (DAC) and an audio codec.

    I swapped some e-mail with these folks, and they assure me that with some component replacements, the DRK will cover HF frequencies. There is more information, including a block diagram, at http://www.cepdinc.com/DRK.htm

    Filed Under: Software-Defined Radio