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Hi all, I am back from a few days of vacations, and I have found some questions to answer. > Who someone knows what are the "WF", "SP" and "Dec" button on the > right side ? They are just placeholders for new functions. WF stands for Waterfall, SP for Spectrum and Dec for Decoder. These functions probably will not ever be implemented, as I am working on a new program that in my intentions should superceed SDRadio. Due date, October time frame. > 2 - the calibration sound card was impossible until I put a 47k pot in > one of the 2 outputs, the amplitude control had a very small effect > before that. The amplitude control in the Skew adjustment panel has a limited range on purpose, to make it easier to find a null. I had reckoned that the generally the amplitude unbalance between the Left and Right channels is small, and a +- 5% adjustment should suffice. In your case this my assumption seems to not hold. > At -130dBm from my generator, the signal level on the display is -110dB The level reported by SDRadio is of course a relative one, as it depends, among other things, on the settings of the Windows mixer, the setting of the volume knob of your hardware. etc. What is important is that, for a change of xx dBm of your generator, the display of SDRadio shows an equal amount of change in the displayed dB. > 5- The denoiser is very useful but quite desorienting...,it really > cleans the noise from audio and listening is more easy. > However, there is a significant loss of audio level when it is IN and > the global S/N remains about the same. The audio gain (control panel) > has to be increase merely to recover the same audio level in the loudspeakers. The denoiser is based on the Widrow-Hoff method, and its results depend on some parameters that enter into the equations. I chose them just by trial and error, listening at the filtered audio. They have changed from V0.94 to V0.95, and I have been told that V0.94 worked better... probably in the new program I will make them user-selectable. > 7- Band pass : > The reduction of the band pass (ie CW mode) does not appear very > attractive, the audio sounds rough and the improvement is not obvious > in my opinion. I am not sure I follow you. SDRadio does not have an explicit CW mode. The two sides of the receiving window are individually draggable to be placed just below and just above the CW signal of interest. When doing this I found that the filtered CW signal is very clean and free of QRM/QRN. But maybe I have misunderstood you. > S1 = -87 dBm > S2 = -76 dBm > S3 = -67 dBm > S4 = -60 dBm > S5 = -54 dBm > S6 = -47 dBm > S7 = -40 dBm > S8 = -33 dBm > S9 = -26 dBm > "S10" = -20dBm An interesting chart, thanks for having measured it. But please note that the markings on that level indicator are not meant to be S-Units. The meter just shows the averaged amplitude of the incoming signal, evaluated on a buffer-by-buffer basis, on a logarithmic scale. With some additional effort it could be modified for an S-unit scale, though. > I wonder if the I/Q output is really a major advantage instead of > single channel. > Using I/Q output, does the sideband selection is provided by the > software or must I add a sideband switch ? It all depends whether your hardware has a mean to discriminate the wanted from the unwanted sideband. If you have already suppressed the unwanted sideband, the only advantage that I/Q processing gives you is a doubling of the received band, i.e. sampling at 48 kHz will give you 48 kHz of useful range, not the 24 kHz that you would have with a mono input (remember Nyquist). On the contrary, if you cannot suppress beforehand the unwanted sideband, like in a DC (zero IF) or near-DC receiver, then the I/Q processing is the only way you have to get rid of it, up to 70 dB of rejection, with a proper balance. The selection of which sideband to keep is done by the software. Ok, maybe I have other messages to answer to, but I will leave that for tomorrow. It's almost 1 AM, and I am sleepy...:-) Good night 73 Alberto I2PHD
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- [soft_radio] Display menu F6EHJ
- [soft_radio] Back from vacations Alberto, I2PHD
