[OZAPRS] FT8 for HF APRS ?

Sat Dec 2 10:57:06 AEDT 2017

8 PSK carriers 

Ok 9 – the 9th is a clock 

8 bits in parallel

To avoid fading 

Andrew 

From: OZAPRS [mailto:ozaprs-bounces at aprs.net.au] On Behalf Of vk4tec at tech-software.net
Sent: Saturday, 2 December 2017 9:54 AM
To: 'Australian APRS Users' <ozaprs at aprs.net.au>
Subject: Re: [OZAPRS] FT8 for HF APRS ?

VK4TEC,$GPRMC ……………………………….

What else do you need ?

Baloon RTTY 

A

From: OZAPRS [mailto:ozaprs-bounces at aprs.net.au] On Behalf Of Mark Jessop
Sent: Saturday, 2 December 2017 9:51 AM
To: Australian APRS Users <OZAPRS at aprs.net.au <mailto:OZAPRS at aprs.net.au> >
Subject: Re: [OZAPRS] FT8 for HF APRS ?

FT8, JT65 and similar are far too restrictive for something like HF APRS. They are quite specifically designed for making short QSOs, not for passing of arbitrary data (though is is possible, in a limited sense). Take a look at the JT65 spec and you will see what I mean.

The concept of a MFSK-based mode with *good* FEC is still a good one though, but you'd probably be better off either rolling your own or starting from something like THOR or Olivia.

Would the AX25 packet format still need to stay? If you could drop that it would give a lot more flexibility... 

73

Mark VK5QI/VK4

(Currently SW of Longreach...)

On 2 Dec. 2017 08:15, "Glen English VK1XX" <glenlist at pacificmedia.com.au <mailto:glenlist at pacificmedia.com.au> > wrote:

I have my own low bit rate HF capable position/ aprs reporting modem etc but I was thinking at FT8, given the widespread use, would make a good replacement for FSK300 (which is dumb arse poorly suited with no FEC on HF), and that the decoders allow for multiple simultaneous overlapping transmissions in the same BW.

doing a port for dire wolf would be fairly straightforward.

glen Vk1XX

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