CAT control of my KX2 works from the sotacat.local page in my iPhone browser. I can transmit CW from the sotacat.local page. I then launch Sotamat from that browser page, select “SotaCAT” as the transmission channel. I press the “Transmit” button. The button briefly changes to “Preparing radio”, then changes back to “Transmit”. The radio does nothing.
I’m a new SotaCAT user, but not a new Sotamat user. I purchased my SotaCAT assembled from Inverted Labs, and am trying to use it with my KX2.
After updating the SotaCAT firmware and following all the configuration instructions, almost everything seems to work, except the actual transmit of the FT8 to spot via Sotamat. The cat control from sotacat.local works very well. From the web browser I can command my KX2 to send CW and it works.
I believe I’m running the updated versions of everything. Latest SOTAmat app from the App Store, and latest firmware download from https://sotamat.com/sotacat/
I can connect the SotaCAT via USB to my PC and monitor the console using the “Connect” button on the https://sotamat.com/sotacat/ page.
When I use sotacat.local to launch the Sotamat app, in the SOTAmat app I can select “SotaCAT” (as opposed to Network or HF FT8 Audio). When I push the Sotamat “Transmit” button to send my spot command, the button changes to “Preparing radio…” for a second, and then the button changes back to "Transmit. Nothing happens on the KX2. No transmission. No error message from the app.
I also tried SotaCAT with my KH1, again CAT control works but the Transmit button changes to “Preparing radio…” for a second, and then the button changes back to "Transmit”. There is no actual transmission.
KX2: MCU 3.02, DSP 1.52 reported from the KX2 Utility
SOTAmat V2.2.2 build 122 reported from the SOTAmat app.
SotaCAT version: K5EM version 1 build date 2026-03-23 09:32 reported from sotacat.local
I would suggest you contact Brian (AB6D), the developer of SOTAmat directly. He is super helpful and can probably diagnose your issues immediately. Brian’s email address is on his QRZ page. I am an avid use or SOTAmat and also have a SOTACAT which I have struggled with due mostly to my incompetence with technology. However when SOTACAT works, there is nothing like it.
Paul, VA6MPM
It is when you need to get spotted and you have no cell service!
Spotting is a brilliant use of FT8. We are lucky to have SOTAMat+SOTACat - both amazing projects. My hat is off to everyone involved in these projects.
In a nut shell, Brian figured out how to encode info into an FT8 message. You use the SOTAMĀT app to generate the code (it gets appended to your callsign), then you send the code via FT8. Listening stations around the world (similar to RBN) decode it, and it generates a spot (works for SOTA and POTA).
It works very well. Us CW ops already have RBNHole, but SOTAMĀT works for getting spotted on SSB as well.
Some people love FT8, I love the technology behind how these modulation and encoding methods work but have little interest in operating FT8. If you want to, that’s fine. For me, the computer does everything unlike CW/SSB for example where I have to figure out what is being sent.
However, leveraging extra use out of FT8 seems a jolly cool idea. Many years back there was much talk about using CW spotting to try to spot SSB ops. CW ops are spoiled with RBN/RBNhole. I can remember thinking what would be needed, all the background apps, webservers and extensions to skimmers. It was eminently feasible but being a naturally lazy and idle guy, there seemed like a huge amount of work needed for no benefit to me. It seemed easier to learn CW ad use RBN than write lots of software and persuade people to do things. Brian AB6D decided it was worth doing and this is the result. It’s a great resource.
In some ways I seem FT8 like QO-100. You can buy a QO-100 solution, plug it in and away you go. Or you can build something up out of assorted uWave bits and bobs if you are that way inclined. But unlike tropospheric VHF operation or ionospheric HF operating, an awful lot of QO-100 comes done to a) having the kit b) living in the sat footprint c) pointing at the sat and having QSOs. Many people I have spoken to say that after a few QSOs, the magic of QO-100 vanishes. Similar to FT-8 doing it’s magic. That should not preclude people using the modes it’s just that for me, FT-8 is better used the way SotaMAT does. I think it would be excellent to have a tiny QO-100 station that I can take portable (much smaller than some of the people who have done QO-100 SOTA ops) and have a QO-100 station at home. Then to use the satellite as a glorified Inmarsat or Iridium phone system without the eye-watering costs these systems cost. If you use FT-8 type modulation, it should be possible to get away with tiny antennas/power. Something to ponder when I’m fully retired.
In the meantime, leveraging FT-8 for this purpose seems an excellent idea.
@WU7H Thanks, I’m using a newer version than you of the SOTACat firmware, the one now distributed at SOTACAT – SOTAmāt , so I hope it would be compatible with the current SOTAMAT app v1.2.2. But yes, I suspect something like version mismatches, as everything seems to work except the SOTAMAT app → SotaCAT communication.
@VA6MPM Contacting Brian (AB6D) is a good suggestion, thanks. I see Brian posts on the reflector here, so thought this might reach him. I did also directly email Jay (K5EM) who built my SotaCAT and released the SotaCAT firmware version. I’ll give it a day or two and then directly email Brian if Jay isn’t able to get back to me.
@K6YK SOTAMAT is an interesting system. I’ve been holding my KX2 mic next to the speaker on my iPhone with the SOTAMAT app, with the radio on an FT8 frequency, and it gets me spotted for SOTA or POTA. There’s a bit of a learning curve and setup to do, it’s a little fiddly, but it does work. I’m hoping to do some remote SOTA activations with CW this summer, spotting myself with SOTAMAT.
You may not remember, but you actually spotted me on my very first SOTA activation. I was in an area where there was no cell service, no APRS digipeater and I was doing SSB. You graciously spotted me, probably sensing that I had no idea what I was doing. Now nearly 300 activations later, I still usually find myself in remote areas where there is no way to spot myself in ways most ops are using. Thankfully since Brian developed SOTAmat, I don’t even worry about where I go because I have been able to reliably spot myself using an FT8 signal generated by the SOTAmat phone app to the mic of my radio. It has been utterly reliable over hundreds of remote activations. I don’t know why anyone even bothers with anything other than SOTAmat. In addition to the FT8 function, it has a cell function and a web function as well when you are in an area where you can reach a cell tower.
Paul, VA6MPM
HI Paul,
I had no idea about SOTAMAT. Still not sure I understand it all but if it works,
that’s a good thing. I’m always glad to spot someone if they need it.
My original statement was referring to using FT8 for QSOs instead of CW or SSB.
I don’t want to start a thread on that subject, it will go on forever.
73,
John, K6YK
@AB6D I was able to resolve the issue. I testing everything with an Android phone - SOTAmat and SotaCAT worked flawlessly with my KH1.
So I took another look at my iPhone.
**
The settings for the SOTAmat app on my iPhone didn’t grant access to my local network. Once I gave SOTAmat access to the local network, it was able to control my SotaCAT device, and everything now seems to work.**
To try to figure out why the SOTAmat app on my iPhone didn’t have local network access, I deleted the app from my phone and reinstalled it from the app store.
On first launch, it prompted me to grant local access and explained it needed access to find SotaCAT devices.
I first installed SOTAmat in April 2024, over two years ago. I suspect back than some combination of: SotaCAT devices didn’t exist, SOTAmat didn’t ask for local access, didn’t tell me while it needed local access to find SotaCAT devices, or I didn’t have a SotaCAT device and so I said no.
While I deleted and reinstalled the SOTAmat app, I also I got a message about updating SotaCAT firmware to a Feb 15 2026 or newer version. I don’t recall seeing that message before, likely since I’ve had SOTAmat on my phone since April 2024, over two years.
Perhaps there are a couple of important messages the SOTAmat app displays when you install it the first time, but doesn’t display them if you have been a user for a couple years. Or perhaps I was distracted and clicked through them without paying attention.
Perhaps this post will help someone else.
Thanks to @AB6D and @K5EM, the combination of SOTAmat and SotaCAT is a glorious system and it is very useful.
