Having attended a short talk by Steve M0SHQ at Essex Ham about operating Amateur Satellites, and seeing Steve work the ISS via APRS, I decided to have a go myself. I built the dual-band beam he recommended several times, but the design always measured up poorly. In the end I tweaked the design somewhat, and come up with something myself – it’s all credit to the original designer, I just optimised it with some antenna modelling software. Details on the antenna can be found here: Dual Band Satellite Yagi.
Over the past week or so, I have been playing around with DStarRepeater and ircDDBGateway to learn a bit about DSTAR repeaters, given the progress GB7KH‘s NoV is making. I have made a simplex hotspot with my FT817 and a soundcard interface, although I can see that there is certainly room for improvement. I have ordered a DVRPTR_V1 GMSK interface which has been dispatched so that will replace the soundcard, lowering the CPU load. I am to have the system set up on a Raspberry Pi 2 B, which was released yesterday (maybe today actually). I think I now understand how to tune up those Chinese notch filters, too.
Today I finished my 4 month stint at ARM Ltd. During my time I haven’t done much with the website, but I have been working on my implementation of a fully KISS compliant Arduino TNC as well as using DSD 1.7 to decode digital modulation such as D-STAR and DMR (and others) using my FunCube and RTL-SDR receivers.
Over the weekend I worked on my 1.25 kW solid state PA based on F1JRD’s design from Dubus using a MRFE6VP61K25H. I bought a complete kit at the Friedrichshafen Hamfest 2012 from F1JRD and F5CYS and built it up late 2013 but due to problems, I never had more than around 40W output. This weekend, with a new set of capacitors from ATC I rebuilt the output matching and fired it up once again. With my 1kW/50V power-supply I can get around 600W output, which his more than enough. This is still a work in progress, but things are moving forward with the project.