[aprssig] APRS Messenger...important update

Chris Moulding chrism at crosscountrywireless.net
Wed Feb 20 05:11:56 EST 2013

Over the last two weeks I've been making some modifications to the APRS 
Messenger program so that it will work with a PSK-63 APRS GPS tracker 
being developed by Mike Berg, N0QBH.

Over the years Mike has developed several APRS trackers using Microchip 
PIC microcontrollers and I already use some of Mike's code in the APRS 
TNC Digi Tracker.

Mike had developed a PSK-31 beacon so recently he got in touch with me 
to see if we could work together to get a PSK-63 GPS tracker he was 
developing to work with APRS Messenger. His new tracker design uses 
Mic-E APRS encoding to generate a very short PSK-63 packet but as APRS 
Messenger has some software filters to eliminate spurious decodes 
appearing in the HF traffic box his beacons couldn't be received.

I've modified the data decoder in APRS Messenger to improve the 
rejection of spurious packets without the text filters. Mike has also 
added the CRC checksum to his PIC firmware so that it's compatible with 
the APRS Messenger format.

Three days ago Mike sent me a screen shot showing his PSK-63 beacon 
being received by APRS Messenger for the first time. This week he will 
add the beta code to his web site once he's drawn the schematic. He will 
be looking for volunteers to make beta versions of the tracker.

I've uploaded the new version (v3.26) to the CCW web site and the CCW 
Yahoo group files section. I would like to request that all users of 
APRS Messenger especially those running igates update their software to 
this version as soon as possible. It will allow Mike and those 
volunteers who build the beta version of the tracker once it's posted on 
his website to test and send their APRS over PSK-63 beacons to the 
APRS-IS for testing.

The web page for APRS Messenger is:


Mike's PSK-63 tracker will appear here this week:



Chris, G4HYG

Chris Moulding
Cross Country Wireless
7 Thirlmere Grove, Bolton, Lancs, BL4 0QB, UK
Tel/fax:     +44(0)1204 410626
Mobile:      +44(0)7752 391908
Website:     http://www.crosscountrywireless.net
Yahoo group: http://uk.groups.yahoo.com/group/cross_country_wireless/

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