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| SDR Sharp - brilliant stuff for FM (and not only)! https://forums.stereotool.com/viewtopic.php?f=4&t=5686 |
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| Author: | Bojcha [ Wed Feb 10, 2016 1:34 am ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
Quote: A few pics of Serbian radio stations, made by my friend in Belgrade.
http://i.imgur.com/Z6EPw2G.png http://i.imgur.com/CfMVtq5.jpg http://i.imgur.com/eVxceMN.jpg http://i.imgur.com/vlffj4C.jpg http://i.imgur.com/Pxdh6Et.jpg Video will soon follow! 
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| Author: | Slawomir B. [ Wed Feb 10, 2016 8:35 am ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
Quote: Hello everybody!
Like this:I'm "the guy" who made those screenshots posted above. Unfortunately I don't have (or I can't see it) an option for 150kHz bandwidth, here is a screenshot from HDSDR:   So - samplerate stays 192 kHz, but you need to narrow FM bandwidth to 150 kHz (the closest I can come with HDSDR is 150.977), otherwise the mpx output is about 20% too low. OR compensate for the 20% offset (in mpx tool for example). By compensating the signal in MPX tool itself you can actually listen and measure slightly overmodulated signal accurately. Here the measurements I get from one radiostation that has solid signal in my area: 150 kHz BW - pilot 9.5% (+/- 0.1%) 192 kHz BW - pilot 7.5% And I'm pretty sure 9.5% is accurate Bojcha used different method, with modified tuner that has mpx output - it's the most accurate way of measuring signals, provided you know how (and are able to) calibrate the whole system, including line input in your soundcard. |
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| Author: | domo-kun [ Wed Feb 10, 2016 7:16 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
Thanks a lot! Totally missed that, as a matter of fact it wasn't even visible to me, I had to click on AM then back to FM to get that slider, and as you said the closest bandwidth is 150.977 I'll post new pictures in a few days! |
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| Author: | Bojcha [ Mon Feb 22, 2016 1:18 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
I should like to thank Slawomir for sending me a one USB dongle with RTL2832! Now i can play with it too Thanks Slawo! |
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| Author: | Slawomir B. [ Fri Feb 26, 2016 11:29 am ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
Oh dear No problem! 
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| Author: | bigic [ Mon Mar 07, 2016 5:34 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
From rtvforum.net Quote: Radio S 94.9MHz 150 vs 192kHz http://i.imgur.com/boAglJq.png http://i.imgur.com/vZEhNjG.png Play/b92 92.5MHz 150 vs 192kHz http://i.imgur.com/4QvAQux.png http://i.imgur.com/Jc2fQOI.png RB1 95.3MHz 150 vs 192kHz http://i.imgur.com/ywO1gJw.png http://i.imgur.com/5ccZVNF.png |
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| Author: | bigic [ Sat Mar 12, 2016 7:46 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
The promised videos are here! Both videos are password protected - the password is rtvforum. Domo-kun sent them to me via private message. Play 92.5: http://www.dailymotion.com/video/x3xg55u Radio S 94.9: http://www.dailymotion.com/video/x3xg5ob Both videos are showing speech segments. I don't understand why bandwidth increase does nothing to the distortion in the Play 92.5 video? |
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| Author: | domo-kun [ Sat Mar 12, 2016 9:05 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
Here is one more, Radio Beograd 1 on 95.3MHz, same password... http://www.dailymotion.com/video/x3xh5u9 |
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| Author: | Slawomir B. [ Mon Mar 14, 2016 12:11 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
Quote: The promised videos are here! Both videos are password protected - the password is rtvforum.
Might be multipath - please note how asymmetric the signal is. Maybe received signals were overlapped with the reflected ones. I've seen same while testing the receiver between tall buildings.
Domo-kun sent them to me via private message. Play 92.5: http://www.dailymotion.com/video/x3xg55u Radio S 94.9: http://www.dailymotion.com/video/x3xg5ob Both videos are showing speech segments. I don't understand why bandwidth increase does nothing to the distortion in the Play 92.5 video? |
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| Author: | bigic [ Mon Mar 14, 2016 2:01 pm ] |
| Post subject: | Re: SDR Sharp - brilliant stuff for FM (and not only)! |
92.5 and 94.9 are coming from the same transmitter location with similar power, yet 94.9 has no distortion (except that induced by Optimod) so I doubt it's multipath. About the asymmetric signal, you think of the 95.3 signal? That's because 95.3 is running without audio processor, so there is nothing to symmetrify asymmetric voice. |
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