David De Coons, WO2X, and Michael Walker, VA3MW, published an article describing how to use Node-RED to control ham radios in the September 2021 issue of QST. I had chatted with Dave a couple of times on the Flex Radio forum while I was integrating Flex Radio control into CTR2. I knew Dave was working on Node-RED but wasn’t overly interested in it because I was so focused on this project. I thought it was interesting that we both published articles in ARRL magazines in the same month essentially describing how we approached the same problem from different directions.

By a quirk of fate (and a little confusion at ARRL), a link to this blog was inserted into the first paragraph of Dave’s article. That little mistake got me thinking, could Node-RED be an option to the Nextion display I am currently using?

As of September 5, the short answer is, “I’m pretty sure”. I’ve spent the last week playing with it and have a some functionality working. I’ve roughed out the basic Home page, though it is constantly changing as I develop the code behind it. Not everything works yet, but it’s coming along nicely. The FFT display was my biggest concern and after a lot head scratching I got it running. The graph in Node-RED has several formatting options so I was able to reduce the number of bytes I had to send to update the FFT display from 350 to 70.

The lead photo shows my Xiegu x5105 selected, (R: 2), on antenna 2 (A: 2) listening to 40 meters FT8. I have the low pass filter set to 2400 Hz as shown by the violet trace on the FFT graph.

Node-RED adds a lot of functionality with a slick user interface and the ability to control CTR2 from your shack’s PC or remotely from the Internet. It even looks pretty good on my smartphone. It will also be much better that using the Nextion simulator I described in this post.

I’m just getting started on the Node-RED road. From the looks of it, this is going to take several months to implement, so be patient. I don’t have a clear idea of what the final product is going to look like, or how functional it will be on a remote link. I still need to work out how the audio is going to be handled. That said, I wouldn’t recommend ordering CTR2 hardware yet if you are planning on using it for remote station control.

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