SOTAMAT out of beta: V1.0 released for iOS and Android (Part 1)

Finally (!) a production V1.0 release of SOTAMAT on all 3 app stores: no more APK side-loads, no more iOS Test Flight beta stuff.

Production Releases (free):

What’s new in V1.0 that wasn’t in the Betas?

  • FT8 audio generation is built-in (except on iPad). No more need for 3rd party apps (though you can use them if you want). This means the Android version is much easier now, and iPhone is a little easier.
  • Auto-repetition (up to 4 times) where each repeat transmission of your self-spot is at a slightly different audio frequency to avoid interference.

And as a reminder: what does SOTAmat do?

  1. One-way commands executed via HF radio (works without internet, cellular, or satellite):
  • Self- spotting via HF (SOTA and POTA)
  • Self- alerting via HF for CW operators wishing to “tickle” RBNhole (SOTA)
  • Select and send predefined SMS messages to predefined recipients via HF
  1. Two-way commands executed via SMS, eMail, or Garmin inReach-eMail:
  • Find Summit-to-Summit (SOTA S2S) or Park-to-Park (POTA P2P) opportunities with recent spots reports
  • Post a spot (SOTA and POTA)
  • Post an alert (SOTA)
  • Get an upcoming alerts report (SOTA)
  • Get information on Peaks, Parks, and Callsigns (SOTA and POTA)
  • Get Weather forecasts specific to SOTA peaks and POTA parks
  • …and more…

Docs at
If you have issues or suggestions, I’m here to help.


Nice job! Lots to explore! Thanks for your work on this.
73 Martin

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Hi Brian,

Seems like you put a lot of effort into this solution that looks very interesting!

I just installed the Android app, registered on the website, did some preparation (SOTA regions and frequencies) and await the approval to use SOTAmat.

Still lots to read, but I will definitely try it with HF/FT8, which can be very handy when you don’t have mobile network and neither APRS coverage.

I’m not sure if one still needs the FT8 Radio app, or does your statement …

… really mean that the Android SOTAmat app produces the FT8 audio all by itself?

Edit: Brian approved me and the FT8 sound is indeed generated by the app itself. So cool that I can’t wait to test it! Due to the FT8 message length limitation, one can’t send a free comment for testing. Would be great, if an additional combination could be used for this test feature (e.g. by adding a comment like ‘test only, please disregard’), if possible.

Thank you for your work!

73 Stephan


This looks like an amazing contribution to the “sport” of SOTA! I will be using this as it develops here in the North Georgia summits area.

NOTE to other readers:
On my Android Samsung S20, I used FT8 from VU3CER in India to make FT8 exchanges on my X6100. I was able to do it with audio and a USB cable (and utilize the app’s CAT control). The cable method used up battery from my phone faster than basic audio. But the cable handles PTT and frequency changes for each band’s FT8.


Stephen Mathews


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Actually what you ask for is already there (and more).

  1. The first test you should try is to use the service to send yourself an SMS message (if you are in the USA or a few EU countries where the SMS works). You use the “Commands” menu to author a set of pre-defined SMS messages and recipients. In the field you can tell SOTAmat to send one of them. So the first test is to define a test message and yourself as recipient. You should try this at home before an activation. See the screen shot.

  2. The second approach is to define a Testing Spot in the Frequencies and Modes screen. One of the “modes” (beyond CW, FM, SSB, etc.) is “Testing”. The testing mode will post a REAL spot on SOTA Watch (so everyone will see it there), but with two important settings: (a) it will list the mode on SOTA Watch as “OTHER”, and (b) it will automatically add comments for you saying “TESTING IGNORE”. Here is a screen shot of defining that configuration:

…and once I’ve defined it, here is what all of my Frequencies and Modes look like (next screen shot). Also note that the “MY NOTES” field is never used by SOTAmat (it is only notes to yourself in the mobile app) except when using SOTAmat to post an Alert for RBNhole tickling (an advanced use case for CW ops).

If on SOTAmat you go to the “ACTIVITY” page, you can see the history of other people trying out the testing feature. So here is a SOTA Mountain Goat running an SMS test and then a SOTA Watch test and then using the service on a peak:

For people who do SOTA and POTA there is a testing mode for POTA which is even better: the POTA organization has a special Park ID called “TESTING” that doesn’t bother other people. If you set up a SOTAMAT Frequencies+Mode setting for “TESTING” in SOTAmat it will map to POTA’s Testing-Park such that people don’t get bothered by it. I’ve asked for the SOTA org to add a special “TESTING” mode in addition to CW/FM/SSB/DATA/OTHER but no luck so far.

There is a lot of documentation on the web site, and in all the videos. I know it is a lot to take in, so I’m here to help. To avoid audio splatter when sending cable-free make sure you read the FAQ’s.

Also, experience has shown me that you should send the FT8 message 3 or 4 times to ensure that monitoring stations pick it up.

73 Brian

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Yes, I used to do something similar when I started. @K6ARK suggested I try cable free and now most of us do it that way for SSB/CW activations. You have to read my FAQ on how to avoid splatter and improve signal to noise ratio. For frequency changes I now use the radio A/B switch to swap between my operating SSB frequency and the FT8 frequency. I can QSY to a new SSB frequency, hit the A/B swap button to flip back to 14.074MHz for FT8, use SOTAmat to send FT8, then hit the A/B button to swap back to SSB operating frequency.

The other advantage of cable-free is that you can hear all the other FT8 stations and know when to hit manually hit your PTT button right before SOTAmat will start sending FT8 audio. SOTAmat also gives you a countdown timer. The advantage is you don’t need cables, you don’t need to set up VOX menus, and you don’t need to un-set those VOX menus. Watch @N1CLC use it one of his first times in this video:

The main concern of cable free is splatter and picking up background noise (birds, etc.). The FAQ walks you through how to address that, and the app has a special exponential volume slider with numeric output for repeatability (assuming you put the phone’s system volume at max).

73 Brian AB6D

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Hi Brian,

Thank you very much for your time and your detailed explanations!

I just tested the 2nd approach, which is the one I’m really interested about (spotting over HF). I first tried it on 20m and then on 40m using the microphone of my TX-500 @10W into a compromised antenna. On 20m, it seems no SparkSDR could receive me, but on 40m G4BRK could catch my signal:
Screenshot (2)

I repeated the TX on each band as suggested, which was four times, so one minute in total, with 51Hz shift on each repetition. I adjusted the volume of the smartphone to just be slightly below the max power indication. Outdoors with wind noise, it will be more difficult to have a good signal to noise ratio. Experiments will tell. The time setting of my smartphone was good enough, but I wonder if I somehow could get the GPS time and see the delta to my phone system time (I think there is an app for that, but I don’t remember its name).

Update: After checking the SOTAmat activity page, I realized that I was received in total by four stations on both bands:

One thing I was wondering, how I could add the /P suffix and as well the country prefix, when I’m abroad, which applies probably to 50% of my activations and that’s where I usually struggle with bad mobile network and APRS coverage. Of course I can tell each chaser when conducting the QSO, but this is a source of error, since most chasers take the call that was spotted, and may forget to edit it, I guess.

All in all, I think it is a very viable alternative to spot when off-grid. Especially for people like me, who don’t have a Satellite device or carry a laptop (e.g. with JS8Call) to a summit. A smartphone and an HF rig with a microphone fits the bill.

Thank you for this cool alternative!

73 Stephan


Hallo Stephan,
Brain gave me access to the beta of this App when it still needed the separate FT8-radio App to create the tones. I made up a simple lead that goes from the Smartphone’s headset socket to the ACC socket on my radio and turned on VOX in the radio (a Xiegu G90) in that way there is no problem with external noises. The cable has no isolators in it it was a simple 4 pint 3.5mm plug lead (taken from a broken earphone/microphone unit) to an 8 pin mini-DIN to suit the G90’s ACC socket. At the time I tested this, I had to change the mic routing from the front to the rear socket but with the later firmware change once a data mode is selected, this change is automatic.

As always YMMV but my experience with the program in the earlier version has been good and I hope to test this release version from a summit, possibly next Friday.

73 Ed.

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Hi Ed,

Thanks for your input and yes, a cable with calibrated audio level is of course superior than using a microphone.

I’ll first experiment with what I already have.
One advantage when using the microphone is that I just have to switch between VFO A (SOTA frequency) and VFO B (FT8 frequency), so no VOX or DATA mode change is necessary.

Theoretically I should also disable the compressor and maybe increase the TX bandwidth, but why bother if it works. On a summit I have a better antenna than the one at home, but the four reports weren’t too shabby. If there is too much wind, I try to shield it with my jacket. I know, at home all seems easy and works…

I think Brian’s solution is an excellent alternative for off-the-grid spotting and I always like to discover new ways.

73 Stephan


Hi Stephan,
I’m not sure which radio you are using however I would expect any speech compression in the radio to only affect audio coming in the microphone socket. Anything fed in by an auxiliary or accessory socket (as is normal with digital modes) should not be going through the speech compressor. If you have been on CW, then I agree widening the tx bandwidth would be a good idea but if you have been on SSB, most times FT8 should manage with the normal setting that you have for SSB.
These are exactly the things that are different between different radio models of course and the reason why it’s good to test the configuration before you really need it.
73 Ed.

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Hi Ed,

TX-500 from Lab599.

Yes, I was using the microphone, no aux input or cable.

True. Since the selected FT8 audio frequency is well below the max. audio frequency, this shouldn’t be a problem at all.

73 Stephan

@HB9EAJ regarding:

That is a good point. These are the kinds of feedback I’m looking for. Since this is a brand new V1.0 release and since I had only 1 international tester, it is overly USA-centric in 2 ways and needs improvement:

  1. It doesn’t deal with /P suffix or country prefix, and
  2. All the SMS functionality (the 2-way commands, and the 1-way sending of an SMS message via HF FT8) are all based on a USA SMS number.

As for #1 I have some ideas on how to add that and will bump up the priority. Essentially I suggest a new column in the Frequencies and Modes table where you can specify what the posting callsign should be (if not your default base callsign), and what the posting comment should be (today the “My Notes” column is never sent to SOTA Watch and is only used to show yourself a comment). In that way you could have multiple line items for “SSB on 20M” with different callsigns (either your default, or with a prefix/suffix added).

As for #2, sending/receiving SMS to/from outside the USA can cost 900% more than in the USA, unless I purchase local numbers for each country (which itself can add up), and even then some countries are more expensive than others. You can find your own country pricing here: and add up two charges: Pay-as-you-go-Phone-Number-Pricing and Pay-as-you-go-SMS-pricing. So if someone wants to fund purchasing a local number for their country for a year plus fund a reasonable number of SMS messages for that year I’m happy to add it. But beyond cost there are all sorts of per-country anti-spam laws that gum up the works (and starting in 2023 even in the USA). The USA laws are based on businesses, and I’m not a business so we’re all waiting to see what will happen to the services next year.

73 AB6D, Brian

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Hi Brian,

Thanks a lot for your feedback!

I’m still thrilled by your service that once it’s setup, it’s really useful when you’re of-the-grid.

Yes, this looks like a good solution!

Yes, SMS can be pricy, especially if you use Twilio for all countries. But configuring different SMS-gateways for different countries can be a tedious job.

Just an idea: why not let each ham that wants to send SMS configure his own SMS-gateway? Since all SMS-gateways I know support email to SMS, you’d simply send an email to the SMS-gateway you have previously configured.
Maybe an oversimplified idea, e.g. I don’t know if these SMS-gateways support 2-way communication. But then again, how much is this feature, or SMS in general used?

73 Stephan

Great . testing


Looks interesting. cant wait to try

Kent K9EZ

3 ways: you distribute it via the three most rapacious USA tech corporations, which are blocked for many, or perhaps most of the worlds cellphone users (thanks Donald), and all of which have faced legal action over abusive app store practices.

Package as APK’s not Google’s anti-competitive AAB format, that only works via play store.

Distribute it through a non-USA alternative app store like ,, and

Or if you don’t like the sound of that, just keep APKs on your website, and additionally you might try fdroid if it is open source.

Oh well off to try and install on my sons Android, then export the APK, and copy it across to my phone to try… In the words of Titus Oates: “I may be some time”


@ZL1THH APK files are available. On the homepage search for APK, there is a link to all the builds. The V1.0 release build is 42 (or any number over 40). Don’t let the “development builds” scare you: all builds are development builds before they are tested.

I do plan to open source the client side code once I port it to the MAUI framework since it is currently on the prior platform. The server side code is planned for escrow with the SOTA org but needs the docs cleaned up.


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I found OneDrive folders.
On windows it wants an MS login, and isn’t accessible.
On Linux the is an AAB file, which is not installable.
I see there are some earlier APK’s to try.

Ok so 1.0.41 APK installs. (my earlier attempt to install the 1.0.42 AAB on android, then use APKExtractor produced an installable APK, but the app didn’t run)

Excellent: 1.0.41 runs on SailfishOS (under alien dalvik)

I searched for the Apple app store, and nothing shows up.

@W0LMS You are right that it is hard to find in the Apple App Store because of Apple’s search algorithm. When submitted to the app store they allow me to specify search keywords (ex. “SOTA”, “POTA”, “spotting”, “summits”, “sotamat”, etc.) but then their algorithm doesn’t give weight to those same keywords even if you type most of them in. There are a lot of articles on the web about software developers trying to understand how Apple’s search works (or in many cases, doesn’t). The Apple algorithm appears to place much more emphasis on popularity than on keywords, which means new apps for small communities have to do their own publicity [hence this blog post!].

The only search string I’ve found that works is:
sotamāt sota / pota spotting
…but you have to type it exactly like that, including the funny “ā” and include the “/”.

The far easier way is to just click the link found on the homepage, reproduced here, while you are on the iPhone:

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