Hi,
A GNURadio generic SNR calculation routine is built as an extended Python block. It takes a IQ data stream (usually a narrow one - a few kHz) and gives SNR as a real number. It takes one optional parameter FFT size ( 1024 seems a good value). The way of doing it is to log power FFT input signal and then take the difference of the max and the mean values.
Posts by SV1BDS
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Hi,
It has 'long' time before stopping power. I use these with 0.5 mm wire coils not SMD.
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Hi,
Have you test that if the LNB plug is shorted the fuse is burned and not the coils?
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Hi,
A GNURadio generic SNR calculation routine is built as an extended Python block. It takes a IQ data stream (usually a narrow one - a few kHz) and gives SNR as a real number. It takes one optional parameter FFT size ( 1024 seems a good value). The way of doing it is to log power FFT input signal and then take the difference of the max and the mean values.
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Hi iw5bsf Roberto,
I am not sure about your setup so I must not give you any information as they can be wrong.
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Hi,
I have a nice FDX QSO with DL2GRC Nina using SDR Console. For me to avoid confused by my own voice I use the Full duplex option together with Receiver mute enabled in Transmit options at 75%. To avoid PTT, VOX was used and it was possible to talk and hear full duplex without problems. We have to overcome the half duplex way of operating (saying over etc).
The progress in developing code in GNURadio showing that in order to have results, the CPU power is not enough.
The next step is to try to schedule a more than two persons QSO in order to see it in practice. If any one is trying it lets share with us it's experience.
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Congratulations !!!
It seems that the reason for not yet received by me is that I try to decode signals without pilots on. I have sent a IQ dump of the WB beacon (pilots off) to Igor and he promised to see why I can not decode it. Also I notice good SNR in your Rx.
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Hi,
A out of topics HF spectrum analyzer project.
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Hi,
In order to align my portable system dish (but not only to this), a ICOM Q7 used as a portable 739.5 or 740 MHz FM receiver seems suitable to do the job. A set of a 10 dB and a 20 dB attenuators give proper S meters readings used in any combination. Any similar experience?
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Hi,
I am in direct contact with Igor. When I have successful results I will post it here.
It seems that his effort is supporting pilots on, so maybe code with pilots off is not working so good.
The problem now is to successfully decode LDPC packets.
Thanks for the answer hb9dug !!!
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Hi,
After a lot of tests the solution to Winzel low phase noise GPSDO, which have big frequency variations due to thermal stabilization internal circuit, was to run the Lars original software with TC = 16. The Alan deviation was improved, but most important it stopped to unlock as big TC leads to PLL unlock.
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I took the copper caps like yours I have to make the center hole, did you measure the loss of 2.3ghz?
Hi Roberto,
It depends from the feeding wires (probe) length.
For more info see the W1GHZ guide : Link
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Hi,
The results of phase noise improvements in GPSDO.
Receiving is with 90 cm offset dish, modified Octagon twin LNB.
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Hi,
The time constant is automatically & dynamically adjusted as Lars code modified by PA3FYM and me.
DEMA is calculated every time and tc increase and decrease regarding GPSDO performance.
These are first results from John Miles, KE5FX software TimeLab.
EDIT: Images have no valid data.
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Hi,
Hardware and software for microcontroller is completed. A voltage value 0-3300 mV is transmitted to USB every 1 sec. BNC connector is giving the voltage to be measured for a scope or a voltmeter.
Link : I will try to feed data to it.
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the control loop is much too fast.
Hi,
Can you explain your consept?
I use Lars GPSDO with 100 MHz OCXO instead of 10 MHz.
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Hi,
Developing a small frequency difference measuring system for comparing the GPSDO with Cesium 10 MHz frequency standard. Here how a 1 Hz frequency difference seen in a digital scope. Data will be captured and plotted.
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Hi,
The results: 3 mW transmitted at 80 cm offset dish with POTY antenna, as received by 90 cm offset dish using a twin Octagon LNB and of course the new low phase noise GPSDO.
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Hi,
The low phase noise GPSDO is completed.
Outputs: 2* 1PPS TTL, Locked (open collector), 100,50,25,10,5,1 MHz sine 10-20 dBm and 2*25 MHz 18 dBm for LNB.
Power supply: 4-30V.