Re: LF: opera coding demistified

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

Eddie =  G3ZJO

From: Graham

Sent: Monday, July 16, 2012 11:39 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: opera coding demistified

And  of course , there  is a  PIC  code  generator  in the  windows   software , that  can be  used , Andy  g4jnt  has a  post  about  using  it  for  driving  a  standalone  beacon..he did  run  op34 / 64  on 136  as a  beacon  early in the  year  ..The only thing  that  is  missing  is the  internet  beacon  alert ,  clock  accuracy  of  0.2%  is needed  to  achieve the  lowest s/n  decodes , Eddie  G3GZO  and  I think  Pete  M0FMT  are  using  standalone   keying   devices

 

73 -G.

 

clock times  for   modes  :-

 

Opera    05: 0.128 s
Opera      1: 0.256 s
Opera      2: 0.512 s
Opera      4: 1.024 s
Opera      8: 2.048 s
Opera    32: 8.192 s

 

From: Markus Vester

Sent: Monday, July 16, 2012 11:18 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: opera coding demistified

Stefan Schaefer wrote

> G.., i have done it. Downloaded ... to my LF PC. Still can't belive it...

... well, I haven't ;-) Out of curiosity, I have instead implemented Guido's excellent guide on Opera encoding 

http://rn3aus.narod.ru/opera_protocol.pdf

in a little Basic program, which outputs the 110... keying sequence for any given callsign.

 

And it works! For a quick on air test, I decided to use SpecLab's test signal generator, modulated by an arbitrary waveform which can be loaded from a text file. To fit to the required data format, I edited the sequence by zero-padding from 239 to 256 symbols, then replacing every "1" by two lines of "32767", and every "0" by two lines of "0", giving 512 samples total. For "Op4" speed, the AM modulator period was set to 0.256*4*256 = 262.144 seconds. Audio output was used to key my TX on 478.63 kHz. I sent for strings on Saturday night 21:30 to 21:47, and within a few minutes, pskreporter.de showed spots from DF2JP, G8HUH, ON6EO and DD7PC.

 

In case you would also like to send Opera without "his master's software", or associate obscure received sequences with possible candidates, the little program and sourcecode is at

http://df6nm.bplaced.net/opera/opera_generator.zip (24 kB)

 

Best 73,

Markus (DF6NM)

From: Rik Strobbe

Sent: Friday, February 17, 2012 11:48 AM

To: rsgb_lf_group@blacksheep.org

Subject: LF: opera coding demistified

PE1NNZ seems to have demistified the opera coding, those interested can read the attached file.

73, Rik  ON7YD - OR7T