HFU HF Underground
Technical Topics => Software => Topic started by: kris on January 08, 2020, 0053 UTC
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The latest version of SDRuno 1.33 is published. Updates now.
https://www.sdrplay.com/sdruno/ (https://www.sdrplay.com/sdruno/)
My SDR-FL-Play works great!
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Only today I discovered the function of shifting the audio band in relation to the center of the channel.
In the Kiwi and SDR Utwente control programs, you can move the left and right audio slopes to remove interfering emissions from an adjacent channel without alignment. That's what I missed in SDRuno, and yet there is such a function!
Place the mouse pointer in the AUX SP audio area. Press the right mouse button and drag the audio area left or right to cut off the interference of the adjacent channel. It works great, right?
- to restore symmetry, click with the left mouse button on the left or right edge of the audio band.
Clicking predefined Filter value does the same.
You probably know how to remove disturbing tones in the audio band using Noch Filter?
We enter RX Control> EXW. In the opened EX Control window, set the N1-N4 cutout frequency and BW.
Unfortunately, it is not as simple and convenient as in the HDSDR program.
If I helped someone, I am happy!
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I found more tricks to improve the audio readability of weak signals:
- SDR receivers (probably not only mine) have a wide audio spectrum which is manifested by high timbre and high level of white noise. Narrowing the listening bandwidth on the AUX Span, to some extent, allows it to be reduced, but when narrowed down too much, the reception becomes unreadable.
I got an improvement by setting the minimum level of Volume, and I pass the audio signal from the sound card to the active speaker / headphones, where I compensate for the low audio level and at the same time the high part of the band is damped.
I know:
> the equalizer could do the same, but my computer couldn't keep up
> an external sound card with lower self-noise can be used
> I did not check the influence of the bit rate on the noise level
- Another defect:
The program has four predefined Notch Filter (NCH1-4).
Setting their cutout frequency requires you to enter the EXW setup which takes time.
Moreover, the frequencies we chose do not always match the FRQ of the interfering audio signal.
> quick matching of these frequencies can be obtained by detaching the receiver from the station's carrier, observing the efficiency of the cutout on the AUX waterfall.
> Notch Filter only works in the upper side of the AM spectrum. If the interfering tone is on the lower side, all that remains is to change the detector from AM to USB.
Mod Synchro AM does not eliminate such a disturbance.
> In certain situations, the interfering tone will disappear if you change the IF Mode from ZIF to LIF or vice versa.
However, the purpose of this operation is mainly to verify whether the station heard is actually transmitting on this FRQ or whether it is a ghost signal.
>Also, increasing the Decimation can improve reception.
These are my personal observations, perhaps described inappropriately, and may not work for you.
Good luck!