Thursday, March 1, 2018

#HF APRS Messenger

Screendump from 1999 UIview map...
The APRS Messenger program provides a simple way to send and receive APRS messages over PSK, MFSK and GMSK modes on HF.

It has been a long, long time ago I was active with APRS. I remember some software called UIview and it was on VHF....let's was in 1999 and you needed to download maps instead of a instant view on google maps like on Wow, that was 17 years ago already. Since then I was more involved and occupied by other things and VHF/UHF never had my real interest. At the time we were only allowed to do radio experiments on VHF/UHF and HF was forbidden for us as tech license holders. Since 2003 we are allowed on all band HF as well. It opened up the hobby for me like I always would like to do.....DXing on HF. But back to the subject, I liked APRS and did various experiments which were not as comprehensive as they would be now. I remember in one occassion I met a Italian amateur who was sightseeing here and driving through with his van. He transmitted his position and the frequency he was listening to on phone. We made a QSO and it was a nice experience and a good example for APRS use. I made a screenshot of the situation which is not as sharp as todays standards, see picture above.

My location as seen on Notice you can even see a
weatherreport at the right side.
These days APRS is built into some UHF/VHF radios and you can view amateurradio stations as well as ships and sometimes other moving vehicles. You can view location and even use streetview to get an idea of the situation. I became aware of APRS on HF via OH8STN Julian and via the facebook group Portable & Digital QRP. We did some tests with FSQ software last year and this time there is a  HF APRS Messenger experiment going on. APRS Messenger is experimental software which is still developed and that makes it interesting. You don't make the usual QSO's with it, it is messenger (chat) software. Ideal for use under emergency situations. It is able to give a position report, you can send and receive short text messages and you can use the software to gain others access to internet (Inet gate) for position reporting and messaging. You can choose from several digimodes which are not time dependent like JT modes. The software, of course, is for mobile use primairely. However you need base stations to "Igate" to the internet. So far there have been a few activity weekends and it seems the program is getting populair.

The only problem I found was the configuration. With the last version it got easier but still I was uncertain how things should work. And I'm still experimenting with it. So far I exchanged a few short messages with Julian OH8STN and he received and forwarded my position report so I could view it on In this post I will try explain some of the config settings as far as I've done it to get the software working. I only use the soundcard setup as most people will use that. But it can be connected to various TNCs as well as the UZ7HO soundmodem.

You can find APRS messenger software here:

Setup screen
1. First of all you need to be at the right frequency. The worldwide frequency for this program is 10.149.7 MHz USB. The simplest way to achieve this frequency is to set the PSK63 audio tone in APRS Messenger to 1500 Hz, and the transceiver's RF ("dial frequency") to 10.148.2 MHz USB. You can choose other audio tones but the sum of both dail frequency and audio tone must be 10.149.7 MHz USB.

2. When you start the program you get 60 seconds to configure your program. This is fast, but if you can't do it within that time just close the program and start it again, all previous changes are saved. Above is my setup. I use PE4BAS-63 the SSID -63 is to indicate that I send PSK63 APRS, though you don't need to have any SSID it's just to indicate you're using APRS Messenger. Not really neccessary, it's your own choice. My computer takes the right soundcard setting automagically but it can be you need to choose the right transmit and receive soundcard. I cannot write about the com port settings to access the PTT to switch your radio on transmit, probabely it works but since I always work with VOX I don't have any experience.

Main screen
3. The main screen is showing after 60 secs or after you press start. You can only listen and see what is showing, but transmitting you beacon is more interesting. So, you press "Beacon ON" it will light green. You can manually send your beacon by pressing "Send Beacon". APRS messenger can send several modes. Choose what suites you. Most of the experimenters use MFSK-16 but PSK-63 or other modes are good as well. Don't worry about receiving the software is capable of receiving all modes at the same time.
Signal meter at the center
of this picture.

4. A hidden feature I didn't see in the manual (which manual ;-) ). You can set the squelch to a preferred position. Just click with you cursor on the yellow line in the signal meter and hold your mouse button. Best position is just above the "noise" indicated in grey. If you don't set the squelch you will only receive the strongest stations and never see QRP signals.

5. You can use a GPS if you have one the indicate your QTH or position if you're mobile. If you don't have a GPS you can enter your coordinates manually in the "Fixed Beacon or Status Text". If you don't like to give your position you can enter a status text if you wish. Or you can do both like me.
The GPS beacon text is created from latitude and longitude coordinates in GPS notation. You can calculate those but easier is to get it from this page: Just fill in your adress and you find your coordinates then use the ones under "DMS".

This is how it should be (example my beacon text, please don't copy but use your own!):


The "=" shows other programs that you can send and receive messages.
The "-" before "" is a APRS icon symbol. In this case it shows a house on the map. But there are other icons you can use. See for a list here:
""is my beacon comment but you can choose any text you want of course.

If someone else receives this beacon and relay it via the Igate you location will be shown on the map from

Screenshot from my phone when I messaged with Julian via remote
6. If you see some calls in the HF station heard box you can try to send those stations a message. Just
say hello, tell about the weather or give your station info. It will be appreciated. All messages are stored and you can find any traffic/rcvd and tx messages in the "Open log file" pull down menu.

7. In previous versions you did need a passcode to identify on a internet server. With the newest version I believe you don't need it anymore. However I'm not 100% shure. If you need a passcode you can google "aprs passcode" you will find a few and choose the one you like most.

Above is a very simple description of the configuration. Just enough to do a experiment. However there are more possebilities and experiments you can do. For a more detailed discription I would recommend the WA8LMF page about APRS messenger.


  1. Hi Bas,
    I tried to send you some messages this morning but this did not work. Sometimes there are messages in the waterfall, but they are not decoded. When sending a message I can do this but then I have to manually activate the transmit button because via com3 USB the PTT button is not activated. Moreover, I do not get VOX talking via data USB. I now work with an ICOM 7410 but I also tried the setup via an FT897D with a microham III modem. Maybe you have some tips. I would like to send a message to you.
    73 Gerard de PA7GMU

    1. Hallo Gerard, ik kreeg al meer opmerkingen over het niet werken van de PTT. Ik heb er geen oplossing voor, zelf werk ik met VOX en dat werkt. Dat je niks hebt ontvangen sta ik niet van te kijken. Heb vandaag maar 1 station ontvangen (OH8STN) en ook een ander station hier in nederland had hetzelfde. Het sturen van een bericht naar mij zal niet lukken, het is geen internet. De afstand tussen ons is te klein om verbinding te maken. Zie dit geheel dan ook als experiment. Het kan lukken of niet....73, Bas

  2. Thanks for the tutorial, Bas! I don't actually accept the US-centric view that amateur radio will somehow allow communications to continue during a nuclear war. But I have been telling the kids this morning about the importance of business and government-independent communication routes. They even seem to understand! I will try to get to grips with this software later today.

    1. Hello John, for those that are unprepared amateurradio is certainly not possible. You need at least a system that is reliable, internet and power indepedent. And you need a variety of antennas. The amount of power is not important. Without propagation you're getting nowhere. 73, Bas

  3. I'm now up and running (probably with a few mistakes here and there!) on APRS messenger.


Thanks for your comment. Bedankt voor je reactie. 73, Bas