Re: 300bps Packet (and EHAS) - what is pam, psk, and newpsk,

[David Ranch <linux-hams@trinnet.net>]

Hello Take,

It's interesting you bring up the newQPSK setting. I've never found any 
comprehensive documentation on soundmodem and what some of these other 
modes are. Do you know? Anybody else on the list know or could comment?

fsk - I know what FSK is but what does it mean in respect to soundmodem? 
My Yaesu FT-950 supports an FSK input and my US Interfaces Navigator 
device does FSK too but how would soundmodem use it? Seems it's slowest 
speed is 4800Bits/sec.

pam - what is pam?

psk - I know what PSK is and I use the BPSK31 mode in Fldigi but what 
would soundmodem do with it in respect to a packet mode?

newqpsk - I know what QPSK is and I've used the QPSK31 mode in Fldigi 
(has forms of FEC enabled on it) but what would soundmodem do with it in 
respect to a packet mode? Seems it's slowest speed is 1000Bits/sec.


I would love to learn what these modes do, are they stable, and maybe 
these modes could be used as a strong alternative to trying/failing 
300BAUD HF packet.

--David

> 900/1100 offset seems to a typical practice for the soundmodem 300bps
> operation.
>
> I share your concern concerning it would not be the practical capability to
> be used at HF.
>
> By the way, does anybody know the implementation status in the radio amateur
> world about EHAS (Hispano-American Health Link) protocol which is originally
> based on radio amateur Linux AX.25 and the soundmodem of both FSK and
> newQPSK modes but adds the several performance improvement techniques like
> FEC, Turbocodes, ARQ e.t.c.? 
>
> The several literatures can be googled by “EHAS”.
>
> Regards,
>
> take
>
> De JA5AEA
>
> ________________________________________
> From: David Ranch [mailto:linux-hams@trinnet.net] 
> Sent: Friday, November 26, 2010 4:06 AM
> To: Tsutsumi Family; linux-hams@vger.kernel.org
> Cc: 'Dave Platt'
> Subject: Re: 300bps Packet
>
>
> I've used the same 900/1100 offset setting for 300baud HF packet with
> Soundmodem and things worked OK I suppose.  I ultimately came to the
> conclusion (as did others in my research) that without a beam and high
> power, HF packet doesn't work very well.  I would get four times more
> retries than actual good packet exchanges from Santa Clara, CA to say 
> Denver, CO. (Google 'Network 105').  For this exact reason, I've been
> tracking the Winmor efforts and it's upcoming kb-to-kb mode.  I hope one day
> we'll see it on Linux where we can get a packet-like mode with real FEC for
> an inexpensive price.  I now can now truly appreciate Pactor2/3 but the
> beyond acceptable high costs of the single vendor TNC and the proprietary
> nature of the mode are show stoppers for me.
>
> Anyway, I have my Soundmodem HF and VHF settings here:
>
>    http://www.trinityos.com/HAM/CentosDigitalModes/etc/ax25/
>
>
> If anyone would like to put together a sched. (might be fun to try), email
> me. 
>
> --David
>
>
> Tsutsumi Family wrote: 
> Dave,
>
> Thank you for your quick reply.
>
> Along with Phill's configuration parameters i.e. f0=900Hz and f1=1,100Hz in
> the separate correspondence, the conclusion seems to be that f0 and f1 must
> be any arbitrary numbers below 1,200Hz and above the low cut frequency of
> his/her TX/RX audio path with 200Hz gap.
>
> As the above conclusion is unique nature of the soundmodem, the fact should
> be widespread to the new 300bps AFSK SSB users of the soundmodem and I hope
> Andrew's pointed sites will kindly cover this.
>
> Regards,
>
> take
>
> de JA5AEA
> -----Original Message-----
> From: linux-hams-owner@vger.kernel.org
> [mailto:linux-hams-owner@vger.kernel.org] On Behalf Of Dave Platt
> Sent: Thursday, November 25, 2010 3:37 AM
> To: linux-hams@vger.kernel.org
> Subject: Re: 300bps Packet
>
> Tsutsumi Family wrote:
>   
> Dave,
>
> Thank you for providing the tutorial of SM source codes.
>
> As one of ways to solve 300bps SSB operation without any code change, you
> are suggesting to use the frequency setting of f0 and f1 to less than 4 x
> 300bps =1,200 Hz such as 800Hz and 1,000Hz, not conventional 2,100Hz and
> 2,300Hz.
>
> Correct?
>     
>
> Correct - I think this ought to work.  As long as you don't pick
> frequencies so low that your audio connection (PC to rig) is
> rolling off the amplitude (due to e.g. transformer isolation
> in the audio path) this approach should let you generate a pair
> of tones with a suitable separation.
>
> You'll just need to tune your sideband rig a bit differently than
> if you were using a traditional "hard" TNC with its receive filters
> tuned for a 2200 Hz channel center.  Just tune to match up the
> tone you hear during reception, with the tone that your PC generates
> during transmission... it'll be an octave or so lower than the usual
> pitch but it should work.
>
>
>
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