Sometimes development projects get cancelled for moral reasons rather than technical ones…

The contents of this unassuming box kicked off all sorts of problems at Cross Country Wireless back in 2014.

It’s the prototype of what was then the proposed Sentry SDR transceiver. This would have had a very wide frequency range from 1.8 to 1400 MHz with a power output of 5 to 10 Watts.

I had placed a few posts about it’s development on the Cross Country Wireless forum and had some interesting technical discussions about it.

The problems started when it was picked up by the Southgate Amateur Radio News as a news story. Nothing wrong with that they were just being good journalists and found a good news story.

The response from the amateur radio community was immediate and very positive. We were still some months away from production but most of the problems had been ironed out.

When we started getting a lot of interest from countries that didn’t issue amateur radio licenses we started to wonder what was going on. Especially when we received emails from countries that were under United Nations sanctions!

It would have been very easy for us to continue development of this transceiver and launch it as an amateur radio product. Even with the transmitter limited to amateur frequencies it would be naive to think that no one would hack into the hardware to give it full transmit coverage.

Unlike existing ham radio transceivers using superhet or DSP technology this was a software defined radio. It could become the perfect tool for electronic warfare. A user could receive and record the most heavily encrypted message and transmit it back 1000 times. Even the most sophisticated communication system would struggle to cope with that level of jamming. And we were about to put it on the market!

I took the decision to cancel the project. It was a hard one to make as I had spent a lot of time and money getting so far with the development. After announcing the cancellation I got a lot of complaints about it and suggestions that I should just carry on and build it anyway as others would do it. Many thought I could make a lot of money from it. Maybe so but I still think I did the right thing and I can sleep at nights!

Today (five years later) I opened up the prototype to take some photos for this blog.

It’s still in a working condition but it’s obviously a prototype cobbled together from several boards. The input and output filtering is a very simplified version of the proposed production version and just used soldered links to swap between three bandpass filters. As it stands it’s got filters for 20m, 6m and 2m. I did enter a 432 MHz contest with the 100 mW output from the driver amp with a separate filter and did surprisingly well.

Other than that I’m not going to go into any more detail about what’s inside it. I might just get it running on 6m again and keep it in the workshop for monitoring summertime Sporadic E propagation.