Posts by PY4ZBZ
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Transparency for oscar locator in 1985 !..
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[Blocked Image: https://www.qsl.net/py4zbz/satelite/mensAO10.jpg]
Message received from OSCAR 10 with an old teletype machine and homemade TU in 1985 !!! https://www.qsl.net/py4zbz/hm/homemade.htm#a
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[Blocked Image: https://www.qsl.net/py4zbz/satelite/msxAO13.jpg]
My BASIC program for MSX and IBM-PC in 1988 ! : https://www.qsl.net/py4zbz/satelite/SATMBAS.TXT
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Only now have I seen the noise and SNR information on Simon's website. I found the algorithm for noise measurement very interesting, in the fantastic SDRConsole software. Now I understand why we don't have SNR = 0 in the absence of a signal.
In SDR # it is necessary to have at least a part of the tuning band in which only noise appears to have a correct indication of the SNR, as shown in the following figures. It seems that this software searches within the tuned band for the largest signal (the signal S) and the smallest signal, which is the noise N, to calculate SNR.
73s de Roland PY4ZBZ
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Thank you all for the valuable answers!
Conclusion on SNR in SDRConsole:
to have a reasonable measurement of SNR, please do not zoom in too much!
73s de Roland PY4ZBZ
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Thanks Olger and Greg,
Ooops.... Ole OZ2OE, my post happened while you did yours, hi hi ...
S/N and (S+N)/N depend on the band in which the noise is measured. What is the band used by SDRConsole to measure noise?
But the zoom applied to the spectrum display should only affect the visualization of the spectrum, and not the S/N measurement.
The visual zoom applied to the spectrum (purely graphical display effect) does not affect the resolution of the FFT and therefore should not affect the value of the S/N?
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Thanks for the answers.
I understood that the 6 dB SNR (and not zero) in the absence of a signal is because the weighting of the noise measurement (average) and the signal (peak) are different.
But that does not explain why the SNR with more zoom increases ...
Could someone tell me what is the power of the FSK beacons transmitted in Bochum and what is the gain of the antenna, or the E.I.R.P of the beacons?
Thanks and 73s de Roland PY4ZBZ
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It seems to me that the SNR measurement of SDRConsole is not correct, according the following 4 images:
Tuning in no signal and without zoom we have 6 dB SNR.
Increasing only the zom and still no signal, the SNR rises to 18 dB !!! In both cases, the correct value would be 0 dB.
With the beacon signal tuned and without zoom, we have 37 dB SNR. Zooming in on the beacom signal has 48 dB SNR !!! In both cases the correct value would be around 31 dB. (37-6 or 48-18)
The SNR should be ZERO with no signal and should not change according to the zoom level!
(I already sent an email to Simon but no answer ...)
73 de Roland PY4ZBZ
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HNY to ALL ! 73 de Roland PY4ZBZ.
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