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Re: LF: Re: OP missed decodes

To: <[email protected]>
Subject: Re: LF: Re: OP missed decodes
From: "Graham" <[email protected]>
Date: Mon, 27 Aug 2012 15:07:09 +0100
Importance: Normal
In-reply-to: <004101cd845a$92615db0$0501a8c0@xphd97xgq27nyf>
References: <06DDBDA2FE814440A956B5C33365FB75@AGB> <[email protected]> <003501cd8452$4ce82780$0501a8c0@xphd97xgq27nyf> <37060B46D79F4AC69EEDBDA79B6B00CC@AGB> <004101cd845a$92615db0$0501a8c0@xphd97xgq27nyf>
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Mal,
 
At the  end of the  day  its  down to  a  contest  of  who  can  code the  better  DSP  engine  as  with  no  DSP engine , there can  not  be  any   pixels'  to  join up  , be that  joined  in logic  or  analogue  using the  mk-1-eb !
 
If you look at the  number  of  stations  running last  night  , then , the  old  , that's  'Joe'   cannot  be  relied on  any more !
 
G..

Sent: Monday, August 27, 2012 2:47 PM
Subject: Re: LF: Re: OP missed decodes

Yes Graham fair logic, but with data modes it is ALL or NOTHING whereas with a one state mode like QRSS there are alwas some characters visible and the message just needs a bit of infill for an ID
In the radio amateur context and especially on LF/mf we probably already know the callsign and the gist of the info being sent.
mal/g3kev
 
----- Original Message -----
From: Graham
Sent: Monday, August 27, 2012 1:08 PM
Subject: Re: LF: Re: OP missed decodes

Interesting  , is   Op  visible    at  -40 dB ? ,
 
But  yes  , it was possible to  re hash a message  if the  ltrs/figs   shift had  been  missed  , but the  signal levels  where  many dB's   higher and  once  the  change to  multi  tone  was  implemented , picalo   etc  , then  error  rates  dropped  and  link  up-times  extended 
 
You are  correct though  , OP  is a  data  mode  , which by  definition  is  two  state  and therefore  will  have a  pass/fail  point , the  beacon  is  reporting  'path  quality'   by s/n at the  Rx  ,
 
This applies to  any  beacon / data  system  , wspr  has a  decode  fail  point  , qrss  has  a  decode  fail  point    sure you can  join the  dots  up , but  if you  need  to receive the  data , then  qrss  offers  no  advantage   Q #  = ?   Q 5 = good  copy , if  you don't  see  the  5  then  what ? guess ?
 
G..

Sent: Monday, August 27, 2012 1:48 PM
Subject: LF: Re: OP missed decodes

Stefan es Co
It is often the case when Data modes cannot be decoded they are visible on the waterfall display. It is also a fact that RTTY can easily be visually read on a waterfall display when it does not decode/print because of qrn hits or qsb.
In the past RTTY fsk marks/spaces were read from undulator tape by a competent operator who knew the Murray code. This method produced better results than direct demodulation/printing
The preferred method on LF/MF surely is QRSS, DFCW for reliability in handling very weak signals then CW for the stronger signals and local working.
de mal/g3kev
  
----- Original Message -----
Sent: Monday, August 27, 2012 11:39 AM
Subject: LF: OP missed decodes

G..,

Am 27.08.2012 13:18, schrieb Graham:
 
DK7FC UZ2HZ 2200m OPERA 1789 kms 23:05:38



Did the program show that decode on your PC? On my PC the decode did not appear! It would be a pity if decodes would be lost. I tried to reach UZ2HZ but thought i wasn't successful. Maybe it was the same with SM2DJK?
Maybe further stations got successful TA decodes but no one knows? Another disadvantage compared to QRSS/DFCW..

73, Stefan/DK7FC
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