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Re: LF: Re: QRSS OP WSPR

To: <[email protected]>
Subject: Re: LF: Re: QRSS OP WSPR
From: "Graham" <[email protected]>
Date: Fri, 27 Sep 2013 20:15:45 +0100
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Engineering  Engineering Engineering
 
Another   -3 dB  at the  Rx in this case is   1000  watts  at the  Tx 
10 db  = 10KW
 
The  advantages  of  Opera  is that  it  works  simple  as that
from  shf to  vlf  with  normal  equipment [very]
 
wspr-15  was  a  ill  conceived  botch  of  a  inefficient  existing  system 
with  increasing  the  time  by  7  , resulted  in a  stability  requirement 
of  x7 as well  and     a decode  engine  that  was / is  not  reliable
and  non compatible  with  average  equipment
 
Opera was conceived , designed , tested  on  simple CW
Tx's and  crossed  the  Atlantic in 3 months  and remained 
stable   ever since , that's  Engineering  not BF&I
 
This  is   radio Ham  , but  not  all  involved  are  amateurs  , some seem
to  take  advantage  of this  , while  others , take the  opposite  view
 
73-G,
 
 
Nb  Why  should  a  CW  tx  cause  key clicks  ?  Opera was designed  with
a  10 mS rise time  cw  envelope , part  of of  a CW tx design is
click  suppression  
 
 

Sent: Friday, September 27, 2013 6:12 PM
Subject: Re: LF: Re: QRSS OP WSPR

G,

Am 27.09.2013 18:07, schrieb Graham:
Which  , if you  take  into  account  , Opera  is  single  tone   on/off    with  app  50% duty cycle  , self  sync  mode
and   wspr  is  a   4 mfsk    externally  time  locked
That doesn't matter at all! A successful detection is all that counts, not the energy (or average power) needed. If Bob can TX 3 kW WSPR-15, then the RF energy is 0.75 kWh. With 50% duty cycle it may be 0.375 kWh but who cares????

 
For the  test to  be  valid , the  wspr  carrier  level  would  of  needed  to  be  50% less  that  of the  Opera  system
No.
Transmitting amateur radio stations have a certain transmit antenna with certain limitations (say 0.1 % efficiency) and they have a PA giving a certain RF power (say 100 W). This results in a certain ERP. The goal of the amateur radio station could be to be received/decoded in a distance as high as possible. It is usually completely uninteresting if you need 0.1 kWh or 0.2 kWh for a transmission, except in /p mode using batteries.

From my point of view the only real advantage of Opera is that you can use a simple keyed VFO, like in CW. But then some will complain about the key clicks :-)

73, Stefan



 
Mr Pixel
 
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