The balconic setup is made up of the following substations, each consisting of an RTL-SDR and a dedicated Raspberry Pi 4, for (hopefully!) round-the-clock monitoring with luarvique/openwebrx:

• 6m.rx-1.async.fi
• 2m.rx-1.async.fi
• 70cm.rx-1.async.fi

On six meters, there’s a simple vertical with no radials, a broadcast FM notch filter, and an LNA. VHF and UHF receivers share a Diamond SG7900 + a broadcast FM notch filter over a splitter/combiner.

Six meter filter and amp are generic Nooelec parts, filter and splitter for VHF and UHF came from SV1AFN. Six meter receiver is a Nooelec dongle, VHF and UHF ones are “RTL-SDR Blog V4”. Cables were tailor-made from Aircell 7 by Paratronic.

Read more...

tldr; I need to monitor the lower portion of “VHF & up”, so that I can get on air once there’s some increase in activity. My home QTH isn’t equipped with any kind of permanent radio station, which means that operating will always require some amount of setting-up and subsequent tearing-down, which I’d prefer not to do if the bands are supposedly dead. There’s also very little room for antenna installation on our balcony, which has been one of the main reasons driving me towards these higher frequencies, where smaller and lighter antennas are a thing, to begin with.

Read more...

Recently, I (Joni OH2EWL) accidentally ended up participating in a amateur radio contest. I was checking in pskreporter.info how things looked like on 6-meter band, and noticed that there was an unusual amount of local (to Finland) FT8 activity going on. Intrigued, I set the station up in the balcony and tried to get into the action. Which didn’t work out right away because, although I noticed that the traffic didn’t look normal, it took a while to understand that what was going on was “EU VHF Contest”. After some fiddling with WSJT-X settings, I was able to get the correct contest mode on and I was in.

Read more...

One of the nodes in my home Kubernetes cluster is running gpsd, and has a cheap GNSS receiver connected to it. Recording what the receiver sees and presenting that in a Grafana dashboard sounded like a nice idea. I wanted to use Prometheus, which is already running, for this.

Main lesson: pay attention when sending stuff on a Go channel; go run -race helped here.

The repo has more details. See also: the Galmon project, where another one of my nodes with the same kind of cheap receiver is feeding.

Read more...

This was long overdue but I’ve finally switched to a modern static site generator. The old system was written by myself in Python 2 many moons ago, and adding posts consisted of writing plain HTML into a monolithic XML source file, then deploying to S3 where Cloudfront served it from. Porting the Python 2 code to Python 3 would’ve likely been tedious, and would’ve still left me stuck with HTML.

Additionally, I’ve recently started moving my non-work efforts away from faraway clouds — partly because of politics, partly because I already get to deal with those enough on a daily basis at work, and partly because of costs — to a machine from a local operator with presence within a few hops and a short ping from our home network. Therefore it felt natural to run the site there, too. Caddy ftw.

Read more...