[OZAPRS] HF modulation techniques

[Mike Zwingl oe3mzc]

ther are currently two options for more efficient modulation techniques
for 
HF-APRS:
ROBUST PACKET MODE (OFDM) and PSK125 (PSKMAIL/PSKSRV)

For Robust PR there is a couple of modems/tncs available from SCS (DSP 
Tracker and PTC-IIex)
Robust Packet uses 8 carriers with 50Bd in 500Hz bandwith with FEC and
CRC.
The DSP-TNC can be used as stand alone Tracker , connetcted to a NMEA GPS
at 
4800 8N1 serial.
This TNC can receive packets plus/minus 250Hz in Robust PR and +-400Hz 
drifted from center frequency!
http://www.scs-ptc.com/datasheets/scs_datasheet_tracker_english.pdf

For PSK125 you need to use a soundcard and Linux on a PC. Test are beeing 
done at 10.148 MHZ also in Europe.
There is a PSKMAIL LIVE CD.iso to boot your Windows-PC in Linux and try 
PSK125.
see: http://groups.yahoo.com/group/aprpack/messages

vy 73 de Mike
oe3mzc/VK3FPF

----- Original Message ----- 
From: "Andrew Rich" <vk4tec at tech-software.net>
To: "ozaprs" <ozaprs at aprs.net.au>
Sent: Thursday, April 12, 2007 11:37 PM
Subject: [OZAPRS] HF modulation techniques


>I am wondering if any higher speed PSK has every been looked at for HF 
>APRS.
>
> I can see some advantages the first of which is tuning.
>
>
> -----------------------------------------
> Andrew Rich
> Amateur radio callsign VK4TEC
> email: vk4tec at tech-software.net
> web: http://www.tech-software.net
> Brisbane AUSTRALIA
>
> _______________________________________________
> Ozaprs mailing list
> Ozaprs at aprs.net.au
> http://aprs.net.au/mailman/listinfo/ozaprs 

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