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[aprssig] New version of APRS Messenger now with MFSK16

Chris Moulding chrism at crosscountrywireless.net
Thu Jul 5 20:50:37 UTC 2012


Over the last few days I've added the mode MFSK16 to the APRS Messenger 
APRS over digimodes program.

MFSK16 is a remarkable mode. It can be decoded down to a signal level 
-13.5 dB below the noise in a 3 kHz bandwidth. That's 2 dB better than 
PSK-31 with better performance in Arctic auroral conditions.

Packets are quite long but it will allow stations distant from the USA 
and Europe to send APRS packets back to the APRS radio network and APRS-IS.

I started work on this upgrade after several APRS message exchanges with 
Damir, 9A3ADE/MM who was sailing on an oil tanker in the Atlantic. He 
told me that once outside HF single hop range of the US or Europe his 
only option was to use exotic data modes to make contacts.

I only released the upgraded program a few days ago and already 
trans-Atlantic APRS messages have been exchanged regularly when 
conditions were poor. At the same time 300 bd AX.25 APRS traffic was in 
the 500 mile range even using the excellent UZ7HO sound card modem.

At present APRS over MFSK16 is being used on 10.1497 and 14.1017 MHz 
(actual RF frequencies) i.e. dial frequency plus audio tone frequency in 
USB mode.

Thanks go to Murray Greenman, ZL1BPU, the inventor of MFSK16 who gave 
permission for MFSK16 to be added to APRS Messenger.

The upgraded version v3.21 can be uploaded here:

http://www.crosscountrywireless.net/aprs_messenger.htm

73,

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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