[RTTY] High Speed RTTY again

[Joe Subich, W4TV]

Yes, MMTTY supports it ... go to the "decode" tab, select 8 bit, 
2 stop bits and your choice or parity. as well as the baud rate.  
It's probably wise to find an optimized BPF on the "demodulator" 
tab as well - particularly if you are using a higher data rate. 

The smart thing to do would be to save both the new BPF parameters 
and the 8 bit settings in a new "parameter" file so you can switch 
settings "at will."  

Note 60 baud 8N1 (ASCII) would have the same throughput as 45.45 
baud 5N1.5 (ITA2/Baudot).  For 8N2, the baud rate for comparable 
throughput is 66.66.  That makes 75 8N2 an interesting alternative 
to 45.45 5N1.5 ... but with about a 25% increase in bandwidth 
(and 1 dB drop in s/n due to the wider filter). 

Given the last of LTRS/FIGS overhead and the slightly higher 
baud rate, 75 8N2 would probably represent a 20% increase in 
throughput.  I leave it to Chen or someone else with access to 
the formulae to calculate the loss of BER from the higher data 
rate. 

73, 

   ... Joe, W4TV 
 





> -----Original Message-----
> From: rtty-bounces at contesting.com 
> [mailto:rtty-bounces at contesting.com] On Behalf Of Jerry Flanders
> Sent: Thursday, January 28, 2010 6:34 PM
> To: roger at g3ldi.co.uk; rtty contesting rttycontesting
> Cc: bartg at bartg.org.uk
> Subject: Re: [RTTY] High Speed RTTY again
> 
> 
> Sure would be nice to get rid of the two-case problems inherent in 
> Baudot. Is there any support for 110 baud ASCII in MMTTY or other 
> widely used digital programs?
> 
> Jerry W4UK
> 
> At 05:25 PM 1/28/2010, Roger Cooke wrote:
> >Hi.
> >
> >  Judging by the amount of emails flying about there does 
> seem to be some
> >interest in 75 Baud RTTY at last!   I have had several QSOs 
> at that speed
> >both on 80 metres and 20 metres with total success. In fact I have 
> >tried up to 110 Baud. Using 170Hz shift within a 250Hz filter width 
> >errors start creeping in at 110 Bauds and even at 100 Bauds, but 75 
> >seems a good standard to aim for. It would increase Q rate in both 
> >contests and DX-pedition pile-ups, but it certainly is 
> stressful on the 
> >typing!
> >   I usually answer points as the other station is 
> transmitting anyway 
> >and then sending at full speed it sure does rattle along.  I will be 
> >calling CQ on 20 metres
> >on Friday at around 1400z at 75 Bauds if anybody wants a QSO.
> >
> >   John, GW4SKA certainly is giving it some thought now for a BARTG 
> >contest at that speed, possibly a short one, but as he says, 
> although 
> >membership of BARTG is free and we would like as many as we can get, 
> >staging the contests does cost, with the certificates and 
> plaques and 
> >things. Small donations add up so please consider making 
> just a token 
> >donation when joining. It will all help
> >sponsor the contests, plus BARTG also sponsors DX-peditions 
> too. If you
> >would like to sponsor a plaque too, that would be really 
> nice!  Perhaps all
> >RTTY contests will move over to 75 Bauds. :-)
> >
> >   The next main BARTG contest is the Spring, in March. Don't forget 
> >the GB50ATG event that is on-going too. There are some nice 
> >certificates and plaques available for that. GB50ATG finishes at the 
> >end of July. Take a look on the BARTG web site, and see if it floats 
> >your boat, cocas your cola, bakes your cake, or diddles your Baud!!!
> >
> >www.bartg.org.uk
> >
> >   Send some feedback. Hey, if you DO join, why not send us 
> some pictures
> >of your station/antennas etc., for the Gallery.   You can 
> even see the
> >mug-shots
> >of the committee on there if you can stand it!
> >
> >See you on the green keys on 75 Bauds Fri PM.
> >
> >73 de Roger, G3LDI, Chairman, BARTG 
> >_______________________________________________
> >RTTY mailing list
> >RTTY at contesting.com http://lists.contesting.com/mailman/listinfo/rtty
> 
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