Re: LF: RXing JT9-2

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

Well  yes  that's true

 

There  are other reason's  as well , some  data modes  are  orientated , in that   if the  Tx  sends  in  usb   , then the  Rx  must  also  be in the  same  orientation  usb  , or  vice versa ,

 

Modes  have   decoder   bandwidths  that  limit the  amount of tolerance  Tx/RTx  may accommodate , if  multi Tx sessions  are to  be  decoded  , then  with  simply  the  'qrg'  then the  Rx  'audience'  are  not  sure  if the  Tx  will   qsy  out side there  pass  band ,   eg , wspr (non hacked) is  what  200 or  300  Hz   wide  , a well known   ook   system  uses  two  audio  pass  bands  to  differentia   speeds  and  another apparently  little  used  data  system  can  accommodate  +/-  40 Hz  in its  MF version  and   +/-  125 Hz in the  HF/VHF  version ,

 

Setting  at the  edge could  result in lost  decodes, as most  are  now invisible  , correct  tx/rx  alignment  is  vital   and  yes  as  Mal  would  say ,  that's  bottom line  for  appliance  operation ,  like  landing on instruments   in the  fog  , everyone  has to  have  the  same  rule book .

 

Close  by  on 500  can mean  upto   50 /60  miles  as  the  ground  wave  seems  to  travel  very  well , all  that  is yet to  come , when  more  users  appear on 500  ,  south  of  Watford-gap   (traditional  test of  n/s  uk origin)   there  was  Beacon-Bedlam  when  the  band  first  filled  with  qrss  stations  effectively jamming   each  other  on rx  ... happy days !

 

73 -G..

 

 

 

 

 

From: wolf_dl4yhf

Sent: Sunday, November 18, 2012 5:13 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: RXing JT9-2

Guess what Stefan meant is the center frequency of his transmission, HF-wise.
And that's less ubiquitous than this 'dial'-thing, because the combination of the 'dial frequency' and 'audio frequency' is irrelevant. Only the sum of both is relevant.
Example:
When tuning to 136.0 kHz "dial" in USB on an analog HF transceiver, plus 1420 Hz audio, the RX covers a range of 136300 to 139700 Hz (assuming the typical 300 to 2700 Hz pass). Assume there is a powerful transmitter near 139 kHz .. anyone close to that transmitter (wink, wink..) will prefer to tune his RX to, for example, 135.0 kHz "USB dial" and use 2420 Hz audio center frequency (assuming a sufficiently configurable software).
Thus the center frequency of the real transmission (137.42 kHz) is all one needs to know.


All the best,
   Wolf .

Am 18.11.2012 16:47, schrieb Graham:

S,,

 

If jt9  is a  multi tone  (mfsk)  system , as is wspr  , then  which   tone  are you  declaring  the  frequency of  ?

better to  use the  dial  convention ,

 

Then  everyone  has the  same (suppressed) carrier frequency and what  ever audio  offset  will  be  unified

 

G) ..

From: Stefan Schäfer

Sent: Friday, November 16, 2012 9:50 PM

To: rsgb_lf_group@blacksheep.org

Subject: Re: LF: RXing JT9-2

Hi Mauro,

I'm on 137.42 kHz (i always tell the TX frequency), yes JT9-2.

73, Stefan

Am 16.11.2012 22:42, schrieb IK1WVQ Mauro:

Hi Stefan,
are you trasmitting now ???

137 dial +  xxxx ????
JT9-2 ????

I am trying to receive you .

73

Mauro IK1WVQ





At 22.30 16/11/12, you wrote:

Thanks Halldór!

Spiros, did you decode the 21:08 and 21:12 transmissions? Is there someone else watching?

73, Stefan/DK7FC

Am 16.11.2012 22:19, schrieb Halldór:

Stefan,
Not very consistent series from me. I am saving all if someone is interested.
 
2100   4  -25   0.7  1423.0  0.00   DK7FC JN49IK         
2102   0  -31   0.3  1429.1  0.00
2104   3  -25   0.9  1423.0  0.00   DK7FC JN49IK         
2106   0  -32  -2.1  1421.1  0.00
2108   5  -23   1.1  1423.0  0.00
2110   0  -32  -1.3  1429.9  0.00
2112   4  -24   0.0  1423.0  0.00
 
73
Halldór
TF3HZ
From: owner-rsgb_lf_group@blacksheep.org [ mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Stefan Schäfer
Sent: 16. nóvember 2012 20:53
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: RXing JT9-2
 
Thanks Spiros,

That looks consistent, you're loosing no single transmission.
The reports look reasonable as well.

Tnx, 73, Stefan

Am 16.11.2012 21:47, schrieb SV8CS- Spiros Chimarios:

JT9-2 on 136 Khz

 
·                     2020 10 -14 0.5 1420.3 0.00 DK7FC JN49IK
·                     2022 2 -36 -2.4 1370.0 0.00
·                     2024 10 -21 0.4 1420.3 0.00 DK7FC JN49IK
·                     2026 0 -39 2.4 1402.2 0.00
·                     2028 10 -17 0.5 1420.3 0.00 DK7FC JN49IK
·                     2030 0 -33 -0.6 1408.9 0.00
·                     2032 10 -12 0.5 1420.3 0.00 DK7FC JN49IK
·                     2034 1 -37 0.8 1426.8 0.00
·                     2036 10 -10 0.3 1420.3 0.00 DK7FC JN49IK
·                     2038 0 -35 -1.0 1436.5 0.00
·                     2040 10 -16 0.4 1420.3 0.00 DK7FC JN49IK
·                     2042 0 -30 0.1 1426.8 0.00
·                     2044 10 -13 0.3 1420.3 0.00 DK7FC JN49IK
 
73, Spiros
SV8CS

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