Some time ago I got a 137 MHz turnstile antenna from Jørn OZ6TA. We decided to build an automated NOAA weather satellite image receiver using a modern SDR device. He also had an Airspy he wasn’t using and so it became the SDR radio we were going to use for this.
Technology
Technology articles and blogs written by Alexandru Csete OZ9AEC.
Can we use a Raspberry Pi model B as FreeDV modem?
I have collected a bunch of old Raspberry Pi model B’s equipped with the Wolfson audio board. You may find these board lying around and collecting dust, as they have been obsoleted by an increasing number of multi-core boards. I will use these boards as simple Softrock SDR receivers, but first I want to do a little experiment. I am going try using them as a headless FreeDV modem similar to the SM1000.
Using the RFSpace Cloud-IQ with CuteSDR on the Raspberry Pi 2
Few days ago, I have been playing with CuteSDR on Linux and Mac and came to think, would this work on a Raspberry Pi? While there is nothing conceptually impossible about running CuteSDR on the Raspberry Pi 2, I often run into obstacles trying to port Qt application to embedded devices, so here are my notes about how to make it work.
Is open source digital voice about to explode?
Digital voice is exploding! That’s the title of HamRadioNow episode 193 where Gary KN4AQ interviews David Rowe VK5DGR, creator of Codec2 and co-author of FreeDV.
Turn your Raspberry Pi into a live HDTV transmitter
Please note that the information in this article is out of date and needs updating. I will do my best to update it soon.
In a previous post I wrote about using the UT-100C DVB-T modulator on linux and I promised to follow up how to use the modulator with live video sources. In this post I am going to describe how to setup the modulator on a Raspiberry Pi equipped with a RaspiCam camera module, effectively turning the Pi into a live HDTV transmitter.
Building the UT-100 driver on the Raspberry Pi
Building the UT-100 driver module on the Raspberry Pi can be done the same way as on the desktop. The only difference is that instead of “sudo apt-get install”-ing the kernel headers and sources we have to fetch them from the Raspberry Pi git repository and install them manually. Although my instructions are written with the UT-100C DVB-T modulator in mind, the procedure is applicable to other out of tree kernel modules as well.
Using the UT-100 DVB-T modulator on Linux
In October last year I learned about the UT-100 series of DVB-T modulators available from a company in Taiwan. At that time I have already been working with software defined video broadcasting; however, I still found the idea of a small USB-stick modulator very appealing for use with embedded devices. In this post I have collected my notes about setting up and testing the UT-100 modulator on Linux.
FM transmissions over FO-29 linear transponder
I have previously written about interference from FM stations on the HO-68 linear transponder. Now it appears the other satellites with linear transponders also suffer from local FM traffic by people who haven’t got a clue that they are transmitting in the satellite uplink segment of the 2 meter band.
Funcube Dongle with Quisk SDR
Today I have spent some time trying the Funcube Dongle with Quisk SDR. The setup procedure was quite painless and the results very satisfactory: Using an Arrow II hand-held yagi connected directly to the FCD I could receive the HO-68 CW beacon with very good SNR.
CuteSDR – Open source SDR for Linux, Mac and Windows
It looks like Moe Wheatley, AE4JY, is working on a cross platform software defined radio receiver intended for SDR hardware from RFSPACE. It is written using the Qt toolkit and will be available soon under an open source license with the purpose of providing an SDR interface program example for other developers. It is still very early and no code has been released yet, but you can watch this first demo video published few days ago and you can also join the CuteSDR Yahoo group if you are interested in following the project.