Message-Id: <201204261339.q3QDd0QR027303@vivaldi19.register.it>
From: "DP engineering" <a.dellimmagine@dp-engineering.it>
To: rsgb_lf_group@blacksheep.org
Date: Thu, 26 Apr 2012 15:39:00 +0200
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Subject: Re: LF: info about better digital mode in 2200m band
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I know for sure that lentus and K1JT's modes are comparable.
They both use the "stadard" definition:  signal power/noise power over 2500Hz band/signal

In my mind roughly : Opera2=WSPR, Opera8=WSPR-6db, Opera32=WSPR-12db
Do you think it's correct?

Opera2=WSPR states that Opera il less efficient (same period for less information). But Opera don't require any kind of syncronization.

LENTUS = WSPR - 7db  For me it's reasonable (same information, more time to trasmit it,  no pseudo-random sequence for syncronization, less "code gain" but more "symbol" gain)

OK, making comparisons is not so easy... maybe also my conclusions are discutable

I5ZPO / IW5BHY Andrea


>----- Original Message -----
>From: g8fzk@g8fzk.fsnet.co.uk
>To: rsgb_lf_group@blacksheep.org
>Data: Thu, 26 Apr 2012 13:49:32 +0100
>Subject: Re: LF: info about better digital mode in 2200m band

>Just one or two  thing's to  check
>
>The  S/N  readings  produced  by  Opera are  referenced to the  SIM - PATH 
>software , so  s/n  levels  shown are  calibrated to a different  standard
>
>The  original  system was  calibrated to be  similar  to fldigi / wspr , but 
>after a  series of  tests   by  members of the  yahoo digital  group,  Jose 
>, felt  these  levels  where  not  realistic and  re calibrated  , giving a 
>lesser reading. Im not  sure  as  what Patrick  has  referenced his  modes 
>to, but if lentus  system is  similar to  jt65 etc  , then you  will  need 
>to add a conversion factor.
>
>As a yard  stick  ,  OP2 @  -26dB  S/N   is  similar to  WSPR,
>
>Also   note the  Op  s/n  levels  are  all  indicated  as  Average , over 
>the  time  line , so  if  you  only  decode  50% of the  transmission 
>(sufficient for  decode) then the  s/n  level  will show  as  -3dB  compared 
>to 100% decode
>
>The  Opera  system  has  also a  QSO  mode  using  the  same  coding 
>system, but  is set to  120 second  TX period  for  15 characters
>and  operates  round  the  -20 dB s/n  level
>
>Set Op to  500 Khz  for  access to the  qso  mode  if wanting to try, but 
>you do need -20 dB s/n for  decode,
>
>ROS-MF7&2   mode  is  available ,multi tone, 99Hz  b/w at  2 baud , this 
>operates at  the  same  S/N   of  WSPR  , but  needs  AUDIO/SDR   Tx 
>facility.  however it is  a  live rtty mode  with no  'time frame' or 'time 
>locking' MF-7 is  6 / 7  dB less, but  has a  chr rate  similar to 
>psk31....
>
>73 -G..
>
>
>>>>The  OP system  is  still  under  development , so  if users  have  any 
>>>>requirements  etc , pls  write in<<<
>
>
>--------------------------------------------------
>From: "DP engineering" <a.dellimmagine@dp-engineering.it>
>Sent: Thursday, April 26, 2012 1:10 PM
>To: <rsgb_lf_group@blacksheep.org>
>Subject: Re: LF: info about better digital mode in 2200m band
>
>> Hi Mauro,
>> At the present, I think Opera is the most widely used.
>> WSPR reaches -27db, not enough for covering long distances on LF. So, it's 
>> rarely used.
>> Opera and lentus perform better:
>> Lentus reaches -34db for  5 minutes trasmission, Opera8 and Opera32 (8/32 
>> minutes trasmission)  reach -32db and -38db respectively.
>> In my opinion, technically speaking, Lentus is the best (it is also very 
>> good for making QSO). Lentus requires a very good syncronization among 
>> station. In addition, if you use a SDR, you may have some problems due to 
>> the latency of the SDR.
>> Instead, Opera is very simple and very close to the "regular" QRSS.
>>
>> So, my conclusions are:
>>
>> For medium distance beacons : Opera8 or Lentus
>> Foe long distance beacons : Opera32
>> For QSO : Lentus
>>
>> best 73's'
>> I5ZPO Gino (operated by IW5BHY Andrea)
>>
>>
>>>----- Original Message -----
>>>From: ik1wvq@stmb.it
>>>To: rsgb_lf_group@blacksheep.org
>>>Data: Thu, 26 Apr 2012 12:27:27 +0200
>>>Subject: LF: info about better digital mode in 2200m band
>>
>>>Hi,
>>>
>>>what is the better digital mode for starting listening 137 KHz
>>>band  as "reverse beacon" (no TX)??
>>>("better" = greater number of active stations in Europe)
>>>
>>>WSPR ?? LENTUS ?? OPERA ??
>>>
>>>what frequency is utilized for those modes ???
>>>
>>>thanks in advance to all ..
>>>
>>>73 de Mauro IK1WVQ
>>>
>>>P.S.: my RX station is : PA0RDT 8 meters over the roof, RACALL 1792
>>>.. not great station at all ..
>>>in QRSS mode the only station what I can receive is the "broadcast
>>>(HI!)" beacon of Stefan DK7FC .. NO OTHER ...
>>>
>>>
>>>
>>>
>>
>> 
>
>