Meshtastic Interference on 868Mhz by temporary traffic lights - wipes out Pole1 Node

After much testing on other nodes I flashed with Firmware 2.5 I up-issued Pole1 to 2.5. I wanted to be able to show which of the local nodes had also upgraded to 2.5 and detect if they had a public key and show a padlock on my live report. I upgraded and edited the website code to show the padlock and all worked great for a few days. We then had warning of A big storm in the UK so a few key nodes i.e. Cranfield Router took down his mast and took the opportunity to also upgrade to 2.5.

I noticed Pole1 was slow to pick up nodes and messages were quiet but I thought this was due to the lack of Cranfield router.

Then Monday the 23rd Sooty one of our local mesh guys popped round as I was building his node into a metal case. After he left he went home and I looked to see if I could see is newly built node and NOTHING!

after a few tests I realized I was not receiving anything but other nodes could see me. I tested I tried other nodes and they weren't receiving too, I tried downgrading software swapping antennas, you name it I tried it. After a post in the Meshtastic Discord I had a PM with Jonathan Bennett from hackaday and one of the Meshtastic developers. He gave me some good tips to try pulling log files from the CLI interface and going into --noproto mode. Again nothing come to light.

Today I noticed there was some local roadworks and temporary traffic lights I had heard these use radio frequency to communicate from one set of lights to another and maybe even remote. Turns out they use 869.40 to 869.65 MHz in the UK. I took my Malahit DSP2 SDR receiver and drove near the site, I drove so I could sit in the car and monitor without looking too weird :)

And there it was a strong signal over a wide bandwith as you can see in the video. This is the cause of all my meshtastic issues of it not receiving any nodes or messages.

The roadworks in question Avon Drive, Bedford, Bedfordshire UK Public Notice All to improve a cycle way.

I can thoroughly recommend the Malahit DSP2 SDR Receiver Its a Russian design but made in China under license. Its extremely solid design machines aluminum covers 10KHz up to 2GHz has inputs for power Hi impedance and 50R antennas full of features can decode CR morse code, RTTY and FT8 in real time plus many other features and perfect for finding the source of issues like this.