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Re: LF: Re: QRSS / beacon test on 503.7kHz

from [Andy Talbot] [Permanent Link][Original]
To: [email protected]
Subject: Re: LF: Re: QRSS / beacon test on 503.7kHz
From: Andy Talbot <[email protected]>
Date: Thu, 2 Apr 2009 21:20:56 +0100
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There is not really any such thing as a hit with this "monitoring software" - it is not a logger as such, just an estimate of the frequency of a peak stable in a narrow bandwidth when measured over the critical  five second period.
 
The left-hand plot you see on the screen covers a spectral plot +/-25Hz on the centre frequency, using an FFT with bins 0.2Hz wide.  After windowing this gives an effective noise-bandwidth of 0.4Hz.    A peak detector looks for the highest bin and plots the amplitude of this in the right hand window. If the detected peak is stable enough then the frequency is determined.   If it isn't, or the peak varies due to noise hits, the frequency isn't logged.
 
What you are referring to as 'hits' are S/N ratio measurements (in a 0.4Hz bandwidth) at the frequency it 'thinks' the peak lies at, ie. at the highest peak detected anywhere in the total span, in the time interval 25 - 30 seconds for each of the three time slots, as defined by the PC's clock with the time offset applied.This corresponds to the third, most prominent, peak on the right hand plot which should hit its maximun at the 30 second marker.  
Therefore, provided the signal hasn't drifted out of the +/-25Hz span range (and I doubt even a ceramic resonator will do that) and provided there is no QRM giving a higher false peak, it will be logged.
 
The noise part of the S/N is measured over the complete minute preceding the three slots. So if there is any signal in there it will distort the noise measurement, and hence the reported S/N

Andy  G4JNT
www.g4jnt.com


2009/4/2 Gary - G4WGT <[email protected]>

Hi Rik, LF,

As the stability of your VXO improved there were many more hits. The log
extract below covers from the 2004utc to 0534utc period with nothing further
from Andy or Rik.

My logging was not reliable before 2000utc as I was updating the PC Internet
Security due to the "Conficker" worm. The software provider sent a full
program release which requires install & setup from scratch requiring a
couple of PC reboots.

It would be interesting if Andy (G4JNT) knows the recommended frequency
tolerance range for the beacon software to create a hit, by the look of the
frequency reports on Rik's signal it does look quite wide.

Gary - G4WGT


2009 04 01 20 00 43.74 22.93 33.75 18.81 -240.00 1499.70 0.00 0.00
2009 04 01 20 15 39.77 22.55 36.38 19.18 -240.00 1499.72 0.00 1486.84
2009 04 01 20 30 40.51 34.00 32.85 20.84 -240.00 1499.64 0.00 0.00
2009 04 01 20 45 46.67 23.94 37.21 19.14 -240.00 1499.58 0.00 1490.52
2009 04 01 21 00 44.89 22.91 38.80 20.23 -240.00 1499.68 0.00 1502.81
2009 04 01 21 15 39.54 21.97 34.88 18.99 -240.00 1499.59 0.00 1502.84
2009 04 01 21 30 37.53 23.49 33.14 18.94 -240.00 1499.56 0.00 0.00
2009 04 01 21 45 31.36 23.22 35.73 17.91 -240.00 0.00 0.00 1501.57
2009 04 01 22 00 27.78 22.54 40.41 17.83 -240.00 0.00 0.00 1501.04
2009 04 01 22 15 48.50 21.96 38.63 17.98 -240.00 1499.66 0.00 1501.82
2009 04 01 22 30 47.78 22.09 40.06 18.25 -240.00 1499.71 0.00 1502.84
2009 04 01 22 45 31.32 21.61 44.30 17.85 -240.00 0.00 0.00 1503.93
2009 04 01 23 00 49.46 21.85 39.35 18.02 -240.00 1499.63 0.00 1504.82
2009 04 01 23 15 46.11 22.74 41.38 18.29 -240.00 1499.61 0.00 1505.74
2009 04 01 23 30 41.99 23.39 41.31 20.76 -240.00 1499.61 0.00 1506.67
2009 04 01 23 45 21.97 22.10 35.56 18.23 -240.00 0.00 0.00 1507.63
2009 04 02 00 00 45.70 22.10 46.86 18.57 -240.00 1499.65 0.00 1508.97
2009 04 02 00 15 43.83 23.03 36.53 18.04 -240.00 1499.52 0.00 1510.14
2009 04 02 00 30 35.93 21.54 46.83 18.43 -240.00 1499.59 0.00 1511.16
2009 04 02 00 45 43.27 22.08 41.79 18.76 -240.00 1499.50 0.00 1512.17
2009 04 02 01 00 37.68 20.93 35.93 18.06 -240.00 1499.60 0.00 1513.21
2009 04 02 01 15 48.91 20.81 38.46 18.38 -240.00 1499.52 0.00 1514.44
2009 04 02 01 30 41.80 21.65 35.23 18.44 -240.00 1499.47 0.00 1515.30
2009 04 02 01 45 42.60 22.41 44.20 19.47 -240.00 1499.58 0.00 1515.96
2009 04 02 02 00 42.41 25.02 33.97 17.90 -240.00 1499.47 0.00 1516.58
2009 04 02 02 15 44.23 20.42 30.82 18.65 -240.00 1499.53 0.00 0.00
2009 04 02 02 30 45.41 21.91 39.86 18.39 -240.00 1499.61 0.00 1518.13
2009 04 02 02 45 35.89 23.48 42.08 18.81 -240.00 1499.50 0.00 1518.92
2009 04 02 03 00 47.61 22.41 25.25 18.70 -240.00 1499.52 0.00 0.00
2009 04 02 03 15 49.08 21.62 34.26 20.01 -240.00 1499.54 0.00 0.00
2009 04 02 03 30 50.78 21.74 41.34 20.31 -240.00 1499.45 0.00 1521.29
2009 04 02 03 45 47.71 23.13 44.08 18.58 -240.00 1499.47 0.00 1522.19
2009 04 02 04 00 40.54 20.66 42.71 19.87 -240.00 1499.40 0.00 1522.99
2009 04 02 04 15 43.52 23.52 35.99 18.49 -240.00 1499.42 0.00 1523.71
2009 04 02 04 30 38.74 24.70 40.90 18.66 -240.00 1499.55 0.00 1524.37
2009 04 02 04 45 43.73 21.67 29.22 19.28 -240.00 1499.43 0.00 0.00
2009 04 02 05 00 37.91 20.91 32.88 18.11 -240.00 1499.37 0.00 0.00
2009 04 02 05 15 42.25 22.47 20.36 18.21 -240.00 1499.40 0.00 0.00
2009 04 02 05 30 29.36 20.74 22.47 18.52 -240.00 0.00 0.00 0.00

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Rik Strobbe
Sent: 01 April 2009 22:10
To: [email protected]
Subject: RE: LF: Re: QRSS / beacon test on 503.7kHz

Gary,

I am using a ceramic resonator VXO intended for normal CW.
It drifted a bit earlier but seems to have stabilzed now.
I re-tuned, now just 2Hz up from Andy.

73, Rik  ON7YD - OR7T




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