Author: Matthew AF7PV

  • Digital Modes Net Explores Fldigi

    The members of the monthly Digital Modes Net have begun experimenting with Fldigi. This “Fast Light Digital” application runs on several different OS platforms and uses your sound card (e.g. a SignaLink) to send digital information over the air. No TNC is required for this mode.

    The Fldigi application provides a chat interface in which text is sent as you type it, but there are additional applications that allow more sophisticated data transfers. Flmsg is one such program; it works in cooperation with Fldigi to send form data, and there is a built-in template for the ICS-213 message form as well as the ARRL radiogram. Flmsg applies a checksum to the form data to detect transmission errors. Similarly, the Flwrap application cooperates with Fldigi to send arbitrary file data, also with a checksum.

    There is an overlap in functionality between Flmsg and Winlink, but one interesting difference is that whereas Winlink is more or less for communication between two stations, Flmsg can be used to send a message to multiple stations simultaneously. That’s also true for Flwrap — it might be used to send file data from the EOC to all field stations in a single transmission, for instance. The data rate is rather slow, so this might be done simplex rather than via a repeater.

    Join the Digital Modes net on the first Tuesday of the month if you’d like to give it a try. Time and frequency details are on the nets page.

  • Featured Member Profile: Matthew AF7PV

    I was born in 1967 in Ft. Wayne, Indiana, and grew up amid the cornfields south of that bustling metropolis. I gradually came to feel that the farming life was not the best fit for me, so after high school I headed to Purdue University and obtained a degree in computer science. Upon graduating I moved to Beaverton for a software development job at Sequent Computer Systems (I remember it fondly) and have been living in the northwest ever since.

    I’m currently on hiatus from software development, and I’m happy to have lots of flexibility in my daily schedule. It was maybe in late 2014 that I went to a Science Pub talk by Dr. Chris Goldfinger of OSU, who spoke about his research on the geological dating of past earthquakes by examining core samples taken from the ocean floor off the northwest coast – during earthquakes there are distinctive sediment layers that form after material from inland landslides washes out to sea. The talk wasn’t about earthquake preparedness, but it reminded me of the idea that I should invest some of my copious spare time in preparedness. Since I’m a rather geeky guy, it didn’t seem to be too much of a stretch to get a ham radio license and join ARES.

    When I took the Technician exam in early 2015, the VEs told me that the General license would also be helpful for emergency communications, so I soon upgraded to General and joined MCARES. I felt like I still had a lot to learn about radio, and studying for the Extra exam seemed like a way to learn some more things, so that’s how I ended up with the Amateur Extra license class despite not being much of a radio person. I’m currently assigned to the PBEM team, which I think is quite a deluxe assignment in terms of the amenities that PBEM will offer after a disaster — electricity, running water, sewage holding tank, etc. I’ve also recently volunteered to host the monthly digital modes training net, during which we’ve been sending each other photos via SSTV. That’s a lot of fun because people send interesting photos, and we may add additional digital modes in the future depending on their predicted usefulness for emergency communications.

    When I’m not sending pictures over the air via SSTV I like to run, do some woodworking, and I play the piano badly. I expect to do software development again at some point.