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Cross Country Wireless APRS Messenger program

CCW APRS Messenger screenshot

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

Features include:

APRS Messenger version 3.38 can be downloaded as a freeware 1.3 MB zip file here .

The latest version 3.38 has a increased number of software receivers for MFSK-4 with a narrower gap betaween them to improve decoding. There are now nine software "receivers" listening for MFSK-4 traffic spaced 6 Hz apart. This gives a total range of +/- 27 Hz. It is vital that users calibrate their receiver or transceiver against WWV on 10 MHz or RWM on 9.996 MHz to make sure it's correctly frequency calibrated or you may decode no stations because you are listening in the wrong place! Some work has been done on the GPS routine to add MFSK-4 and add GPS selectors to the "TNC or GPS" box on the set-up page. If selected the GPS routine will start after the first transmitted packet.

Version 3.37 has a bug fix for a decode problem with MFSK-4. Good packets were being rejected especially if the background RF noise was high.

Version 3.36 has a new mode option MFSK-4. This is a very slow and narrow (176 Hz) mode which is 4-5 dB more sensitive than MFSK-16 at 18 dB in a 2.4 kHz bandwidth making it comparable to FT-8. Beacons are very slow taking typically 1 minute for the shortest callsign and lat/long position packet. Messaging without acks is available for MFSK-4 but watch your message length, the shorter the better. MFSK-4 transmits 210 Hz higher that the usual frequency used for APRS Messenger messages to allow slow MFSK-4 traffic to run without blocking the "fast" channel. On the 30m frequency (10.1497 MHz) used for APRS Messenger traffic the MFSK-4 signal just fits in between the normal traffic and the band edge. Before you use it check the frequency calibration of your transceiver against WWV on 10 MHz or RWM on 9996 kHz to make sure you don't transmit out of band. A checkbox to select 9600 bd GPS receivers is added to the main window, The GPRMC sentence is used for GPS beaconing.

Version 3.35 has a new option to stop the start-up timer on the first page, switches the beacon off during messaging, add metric level squelch for MFSK-16 and a minor bug fix and text change.

Version 3.34 has a modified layout to work better with touchscreen PCs and tablets, the APRS passcode is now hidden and a bug fix to the beacon timer.

Version 3.33 has a bug fix to the port 8500 PTT input and a new UTC clock display in the program frame.

Version 3.32 has a revised PTT control output on TCP/IP port 8500. This makes it compatible with Winmor and other programs.

Version 3.31 has dual AX.25 and APRS over MFSK-16 beaconing and a list of features requested by users for easier use.

Version 3.30 has a bug fix in the digital mode decoder and the check box settings are now saved on program close.

Version 3.29 has upgrades to reduce the amount of APRS-IS traffic when connected to the internet version and a bug fix.

Version v3.28 has more software receivers on GMSK-250 and MFSK-16. It has a modified decoder routine to allow Mic-E APRS packets to be received over HF digimodes.
This allows it to work with a new PSK-63 or MFSK-16 GPS tracker under development by Mike Berg, N0QBH.
MFSK-16 can operate down to very low signal/noise ratios typically down to -13.5 dB below the noise power in a 2.5 kHz bandwidth.
This version has multiple software receivers per mode to improve the receive performance with a revised receiver routine.
MFSK-16 and the GMSK modes are useful as they can be run at full power through a SSB transceiver or Class C amplifier.
It is now possible with this version to remotely control the VHF and HF transmit function with an APRS message sent over HF, VHF or the APRS-IS.
It also has an APRS-IS transmit option to send messages to other radio amateurs directly via the APRS-IS internet system.
This version will run on all versions of Windows and uses minimal CPU resources so will run on older PC's.
It has also been tested running on Linux on Ubuntu 10.04 running on Wine.
This version can now work with the new USB version of the APRS TNC Digi Tracker using any comm port up to 255.
It can also be used with a KISS TNC or the AX25-SCS DSP TNC program as a sound card TNC for 300 or 1200 bd AX.25 APRS.
Received APRS messages are also available on TCP/IP port 8064 for distribution to other programs. This version uses the KISS routine from the discontinued APRS-SCS program written by John Blowsky, KB2SCS.

A Windows installer for the AX25-SCS DSP TNC program can be downloaded here. This will allow the installation of AX25-SCS and the drivers needed for Windows PCs.

A useful web page describing the set-up and theory behind APRS Messenger is available here.

A text document describing the HF APRS over digimodes format in APRS Messenger is available here.

The frequencies used for APRS over PSK, MFSK16 and GMSK are 10.1497 MHz worldwide and 7.0497 MHz in the UK. A frequency of 14.1017 MHz is also used for Net14 APRS over digimodes and testing of APRS over MFSK16 is currently taking place on this frequency. Radio frequency on a SSB transceiver is dial frequency + tone frequency USB or dial frequency - tone frequency LSB. Igates in Europe, US and Australia are already in operation. Please use an SSID of -63 for APRS over PSK, MFSK and GMSK operation. The original program only had PSK-63 hence the choice of -63.

The program will work with serial TNC's that accept the conv and Ctl-C commands for converse operation.

Contact Chris Moulding, G4HYG via

APRS is a registered trademark of Bob Bruninga WB4APR. Click here to view Bob's website.

APRS is an international network of amateur radio stations providing real-time GPS based vehicle or event position reporting, weather reporting and simple message handling for educational, experimental or emergency use. APRS uses a common radio frequency of 144.800 MHz throughout Europe. Digital repeating (digipeating) is used to extend the range of mobile and low power stations over a wider area. In addition to the radio network internet gateways provide a two-way port to the APRS-IS (APRS Internet System) so that stations local to the gateway can be seen worldwide on APRS viewing programs such as Xastir or UI-View.

APRS over PSK and GMSK is a new mode allowing mobile or fixed station APRS operation on HF from remote areas away from the coverage of the VHF APRS network. Using 10.1497 MHz as a common frequency in Europe and the USA a typical range of 400 to 2000 miles from fixed and mobile stations using modest equipment can be expected. There are several Igates operating in Europe and the USA transferring received packets and messages from 7.0497 MHz and 10.1497 MHz to the APRS-IS.

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