LF: Re: R7NT Op32 correlation detection

["mal hamilton" <g3kevmal@talktalk.net>]

This procedure is known as the Fiddle Factor or Guessawork.

I prefer to see the the signal of intercept in real time properly for genuine ID

g3kev

 

----- Original Message -----

From: Markus Vester

To: rsgb_lf_group@blacksheep.org

Sent: Saturday, December 08, 2012 6:03 PM

Subject: LF: R7NT Op32 correlation detection

Alex, LF,

 

the Op32 signal from R7NT was well visible in the 21 mHz TA window. I made two recordings of a 2 Hz band around the anounced frequency, one from 22:08 to 08:11 UT and another one in daylight from 12:06 to 15:25. Then I ran both through my Opera correlation detector, see attached result.

 

The first two lines are a list of several known active Opera stations. Each of these was tried in the cross correlation procedure. The lines below that are the successful hits. Going from left to right, the printed output contains:

 

 time window for correlation (decimal UT hours before / after midnight last night),

 frequency of carrier peak,

 uncalibrated "raw" dB of detected carrier,

 carrier SNR after a "carrier autofocus" procedure, which removes small amouts of chirp and optimally weighs the amplitude for QSB,

 SNR on the Opera scale (ie. carrier in 2.5 kHz minus 4 dB),

 either c or i for a coherent or incoherent demodulation,

 UT hour of the winning correlation peak (corresponds to the start of the transmission,

 SNR of correlation peak in time domain,

 callsign of the winner of the correlation procedure.

 

Now running a recording on 137567 to look for UA0AET tonight.

 

Best 73,

Markus (DF6NM)

 

From: Graham

Sent: Friday, December 07, 2012 8:44 PM

To: rsgb_lf_group@blacksheep.org

Subject: LF: 73! Alex R7NT beacon Op32 on 137.588 now and till to my sunrise(abt 5z)

I start the beacon Op32 on 137.588 now and till to my sunrise(abt 5z)

I plan to acty in QRSS3\10 tomorrow night on abt 137.705
TX abt 60W Output
TX\RX Ant sLoop 200m total length abt @12...18m

73! Alex R7NT