Belmont repeater

Self-contained repeater listening station in my yard.

The feed is currently down - maybe it's cloudy 🌥 🔋

This is a live feed of the Belmont repeater operating on the 2m amateur radio band at 145.430 MHz as heard from a fixed listening station in my yard. The repeater itself is located in Belmont, MA, USA and is maintained by the Minute Man Repeater Association (MMRA) – it is occasionally linked to other MMRA repeater stations.

Click to hear conversation on the repeater. If you hear silence, no one is speaking – gain and squelch have been adjusted to remove any background noise.

This listening station is powered by solar/battery backup power, and may not always be up especially if has been cloudy for several days. The banner above reflects its current status. To conserve battery power, the feed shuts down every day between 0100 and 0600 Eastern Daylight Time.

Where does the live feed come from?

The audio you hear comes from a “listening station” in my yard, mounted to the side of my garden (within a stone’s throw of the Belmont Repeater). The station is built around a Raspberry Pi and an RTL-SDR (software defined radio). Demodulated audio is fed to this server over wi-fi. An Arduino continually tracks an RTC unit (real-time clock powered by a coin cell battery) to power down the radio computer at 1AM and power it back up at 6AM. The RTL-SDR is connected to a half-wave dipole antenna made of copper tubing. The system is powered by a ~30W solar panel and a small SLA battery. Ideally it is weatherproof!

All electronics enclosed in a waterproof box.

How does this help me?

Being new to amateur radio, I found myself experimenting with antenna designs on the 2m/70cm bands (a typical beginner’s activity). However, I found it annoying that anytime I wanted to know whether I could be heard clearly on the repeater, I had to rely on someone responding to my requests for a “sound check”. Depending on the day/time, repeaters are often very quiet (though that’s a different story), so I found myself wanting a mirror of my signal delayed in time. This is possible using a system known as EchoLink, but for a beginner that takes time to set up and learn; I wanted a less cumbersome solution.

Now, anyone in the Boston area can key up the repeater and hear a delayed copy of themselves on the Belmont 2m repeater about 10 seconds later. This could be useful if:

  • You just built a new antenna and want direct feedback on how you sound on the repeater.
  • You’re far away and want to see if you can be heard on the Belmont repeater. Pull out your phone and visit this livefeed. I could have used this recently when I was keying the repeater all the way from the summit of Mt. Greylock (~100 miles away) but had no idea if I was at all discernible.
  • You want to listen to the MMRA network and you don’t want to run extra software on your computer. Just pull this up in your browser.