Listening for a callsign on DMR with Hearham.live

These past few weeks have certainly been trying for some communities with power outages, winter weather and utility failures. Ham radio is a very good way to communicate in your local community, but what if lots of other people are on the local repeater? What if you want a notification if your child or buddy is calling you, but not every other kerchunk or distracting story on the local repeater? If you have a DMR digital radio and id and digital repeater nearby, the tools on Hearham.live may help – and help save your battery leaving a radio on all day 🙂

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Speech recognition made easy

There are numerous howtos for Raspberry Pi and other portable computer voice applications, like this one, but generally they are using Google’s voice api. This may work… when the wifi or network is working, but not only is this sending your voice to google, it requires payment for usage over a certain amount. Users of your robotic application may be not so thrilled when they see it is sending audio samples to Google, and that it does not even work if there is a wifi hiccup! Instead, let’s go through a simple on-device installation that works fairly accurately with no external dependencies!

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Reading Amateur Radio Frequencies with RTLSDR device and Python

There are many cheap ($5-20) USB RTL-SDR devices you can find on Newegg or Amazon that have an unexpected extra of being able to pick up broadcast radio. This is a handy feature, and in fact we can even read ham-radio frequencies by changing the bandwidth and frequency to read. There are excellent howtos on the easy installation of GQRX for just listening to the radio and setting your frequency and listening, and that’s a good way to start with testing your device. In this post I’ll show how to read and listen to radio using just Python and the Python RTLSDR library, which will show a lot more detail in how decoding radio works, and lets you run a clean interface to listen or record radio.

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