Notice for SOTAMAT users

If you use the SOTAMAT software on a mobile device, please see an important message on the SOTAMAT homepage:

The POTA organization has made significant changes to their database which can not only cause failures for SOTAMAT POTA users, but also can affect SOTA self-spotting as well.

73 de AB6D - Brian


Thanks for the heads-up Brian - I will remove the couple of POTA park regions that I added into my configuration and reload the revised “blob”.

73 Ed.

Brian, although I don’t do any POTA activations, so this change doesn’t affect me, I’d nonetheless like to thank you for creating and maintaining the SOTAMAT service and software.

Many of the small-to-medium height summits around here are heavily wooded and often without any cell coverage, and I find your SOTAMAT service to be invaluable in posting SOTA spots when I’ve set up my low-power SSB station.

Furthermore, I’d like to add that every time I use your SOTAMAT software, I’m deeply impressed by how seamlessly it all fits together - well done!

Cheers, Rob


Thanks Brian, good to know!

It seems I was lucky yesterday as I was using SOTAMAT on a second summit in France, because I had poor mobile coverage. Also, as the first summit I activated was a new SOTA summit, I updated the configuration the day before and everything worked as expected.

I only have a POTA location configuration that I wanted to test one day in the near future. Today, after updating the configuration again, the previously existing POTA location was gone (I believe this was due to the change from HB-BS to CH-BS). After changing this single POTA location from HB-BS to CH-BS on, the updated configuration enabled this new location.

So here comes my question after reading your urgent message on for a SOTA and POTA user: Since this only POTA location has already changed, is there still a possibility to corrupt the database?

Thanks again for this great off-grid spotting solution!

73 Stephan


While it might work if your POTA location has already been updated in the database, I would not trust it. The POTA org is not just changing program prefixes, I’ve found numeric database “unique key” values for some locations are being changed. The complexity of tracking every user and every database (SOTA Associations/Regions/Peaks and POTA Programs/Locations/Parks) with every timestamp across all the different services is not simple on the back-end. While it might work, and probably would work, why risk a busted activation? I don’t have time to debug all the implications at the moment, as I am focused on having my code automatically recognize when POTA is changing what used to be immutable keys.

73 de AB6D - Brian


@DD5LP and @HB9EAJ and other experimenters,

You might be interested in my next SOTAMAT project: SOTACAT.
As time allows, I’ve been working with K5EM, KE6TM, KC6X, and KI6SYD on a hardware module for Elecraft KX2/KX3 radios that allows you to connect your mobile device (via WiFi) to the radio for:

  • Click-to-Pounce (see a recent spot list, click to tune the radio)
  • Direct SOTAMAT FT8 synthesis without using audio (the radio directly synthesizes FT8 FSK signals)

You can read about it here: SOTACAT – SOTAmāt

It is still experimental, but very cool. I’ve done many activations with it and it is quicker, easier, and produces a stronger signal.

73 de AB6D - Brian


Thanks Brian,

To be on the safe side, I have removed the only POTA location for now.
Better safe than sorry.

The SOTACAT project looks cool, but a) I don’t own a KX2 or KX3 and b) spotting with SOTAMAT via smartphone without cables works perfectly, so never change a running and reliable system :wink:.

73 Stephan


SOTACAT: that is extremely exciting news for me. I usually am with my dog on summit and every time I “play” the FT8 audio on my phone, he starts howling, which messes up the audio. Its pretty funny, but has limited my SOTAMAT attempts.



That has to be the funniest thing I’ve ever heard regarding SOTAMAT! I absolutely need a video of you on a summit with your dog howling away during FT8. You don’t even need to hit the transmit button, I just want to see your dog howling to the situation.

I will use it in practically every presentation I give! I keep a list of spotting “problems” (no cell service, no APRS digipeater, etc.) and “Howling Dog” is not on my list (yet).

OMG! Fantastically funny,

73 de AB6D - Brian

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Understood, use what works.

What radio do you have? The SOTACAT concept can be adapted to any radio that allows fine grained control over the CW tone during transmission, and that has a workable serial port for CAT control.

SOTACAT isn’t just for spotting: when I can get a cell signal I love the ease of click-to-pounce summit-to-summit control: it will change your band, frequency, and mode for you with one click:

And when I am spotting, it allows much easier cross band spotting (where your operating band is different from your 20 meter FT8 spotting band) because the SOTACAT pushes all the buttons for you automatically and then switches back to your operating mode/band when done. Super quick. It is cable free WiFi and battery operated for up to 3 hours (or more if you use a bigger battery). It is about the size of a stick of gum. Tiny.

But if you don’t need those things, use what works.



Hi Brian,

I mostly use the TX-500 from Lab599 and rarely, when I need a good 2m front end or 2m SSB, the Yaesu FT-818.

Don’t get me wrong, I think SOTACAT is a nifty tool in the tool chain for nerds like us.

If I have mobile coverage, which is usually the case, I spot and check other spots directly in my logging app (VK-port-a-log). This way I don’t have to enter the frequency, mode etc. twice. To find a free spotting frequency, I have to use the VFO on my HF rig anyway.

But I see a niche application for SOTACAT for my use case, i.e. switching frequency, mode, etc. from within the logging app, e.g. after tapping on a received spot. This would need an interface from the mentioned logging app.

With my TRX it’s a press of the [V/M] button, so it’s also very fast.

Unfortunately, this is another battery that needs looking after (or an additional cable). It would be great if one could get some power directly from the CAT connector, but this doesn’t seem to be the case.

Yes, that’s really cool!

73 Stephan

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Is SOTACAT pronounced sota-kate ? :slight_smile:

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SOTACAT: no more fun gambling with PSK31 (said to be not dependable) and getting unexpected responses…

Does anyone know if the FT8 tones work against cows as well ?
I was "cornered " by a dozen heifers whilst activating on Saturday, they ran up and started chewing on the ends of the dipole. One was particularly aggressive and it took about 10 minutes of a stand off before I got them to back off enough to gather up the kit and back away. They came running back and followed for a few yards before stopping.
I only saw some sheep initially and wonder if they were put in later.

Nah, you’re doing it all wrong - you need to mek a sound like a warble fly:

They heifers’ll turn tail and head for t’hills…

I guess that was the problem, someone else had made the sound of the Warble fly and I was on the hill they ran for !

Ah, but this is a skill us seasoned professional old-timer activators have acquired over many years of patient observation of all the critters running free - knowing which hills to avoid, and which to activate. Just in case, pack a good electric cattle prod - that’ll frighten 'em off: