It turns out that I’m perfectly capable of making the same mistake twice. In fact, I seem to insist on doing this.
A couple of years I bought three Heltec devices that were configured for the American market. They worked fine, but only on the 433 MHz network that they use for Lora in the ‘states. For the UK and Europe you need 868 Mhz ones.
A while back Adam told me about a new Heltec Wireless Stick that looked interesting. I was intrigued, so I bought one. The product listing implied that it worked on all of the wavebands.
Mine doesn’t. It has 433 written on the box. It’s a nice enough device, but much less useful than I was planning.
Moral of story: check the transmit frequency of any LoRa device that you might think of buying.