Sunday, October 15, 2023

Latest OpenWebRX on Raspberry Pi 4 excellent

With a little travel on the agenda soon, I thought I'd run up OpenWebRX on a Raspberry Pi 4 in the shack.

The simplest approach is to download the pre-made SD Card image and boot from that.

The "whistlers" I've been seeing on 10m are less today than they were.

Getting started with OpenWebRX using the Pi image is a bit mysterious. There is a setup guide but I couldn't figure out how to log in. They say:

"The default user "pi" no longer exists. Please use the included agent"

What is the "included agent"?

My Pi is headless so to get it on the Wifi network here I had to use the Raspberry Pi imager which let me set a user and password and configure the Wifi.

Once logged in over ssh I created an admin user for OpenWebRX with:

sudo openwebrx admin adduser adminusername

If I edit the /var/lib/openwebrx/settings.json file directly, I found that it would be overwritten unless I forced a restart of openwebrx with:

sudo systemctl restart openwebrx 

Anyway, all good in the end. It works very well on a Raspberry Pi 4 and it's great to have FreeDV, M17 and DMR all built right in.

Friday, October 13, 2023

Put up a dipole for 10m - a very active band

Several people have commented that the 10m (28MHz) band is very active at the moment. Compared to my 80m dipole, a little dipole for 10m was not too much of a challenge.

The first thing I notice is that it's alive with quickly sweeping signals which I don't think are over the horizon radar of anything made by people.

Even in the middle of the day I can hear US stations piling on to DX stations that I can't hear. There's also some AM activity which doesn't sound like hams. I called CQ and got a reply from an Indonesian station that gave me a good report despite his local noise.

Very interesting patterns to be seen:

A commenter on YouTube suggested looking up Whistling Atmospherics for more information.

Sliding down to the old 27Mhz CB band shows that things haven't changed there. Stations seem to be yelling at each other or playing distorted music. There is sideband but also quite a lot of AM in use.

Here's a screen recording of me tuning around a bit using an AirspyHF+ remotely operated using SDR++ in server mode - which I really like.

It's an interesting band for sure. I now have a dipole for each of 80, 40, 20 & 10m. The antenna tree is looking rather busy.