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mission:log:2014:08:08:darc-side-of-munich-hunting-fm-broadcasts-for-bus-and-tram-display-information-on-90-mhz [2015/05/05 18:09]
chrono [Updates]
mission:log:2014:08:08:darc-side-of-munich-hunting-fm-broadcasts-for-bus-and-tram-display-information-on-90-mhz [2019/03/18 09:29] (current)
chrono [Research]
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 datasheet]].  datasheet]]. 
  
-The image in the datasheet is an actual picture of the displays we can find in Munich, so the probability increased even further. At least far enough to hack a crude 3m dipole (aligned horizontally!), pick up an RTL-SDR/E4K stick and hack a receiver in GNU Radio to try to verify that the signal actually exists.+The image in the datasheet is an actual picture of the displays we can find in Munich, so the probability increased even further. At least far enough to hack a crude 3m dipole (aligned horizontally!), pick up an RTL-SDR/E4K stick and hack a receiver in GNU Radio to try to verify that the signal actually exists.
  
 ===== Verification ===== ===== Verification =====
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 Have a look at the following two images, which show the RF baseband spectral views in different sample sizes and different tools, both centered on 90 MHz with other broadcasting stations on 89.5 MHz and 90.6 MHz in the 2Msps view. Have a look at the following two images, which show the RF baseband spectral views in different sample sizes and different tools, both centered on 90 MHz with other broadcasting stations on 89.5 MHz and 90.6 MHz in the 2Msps view.
  
-[{{:mission:log:2014:08:08:fm-broadcast-band-2mhz-90m-center-fftp-spectrum-waterfall.jpg?242|2Msps 90MHz osmocom_fft -F}}]\\+[{{:mission:log:2014:08:08:fm-broadcast-band-2mhz-90m-center-fftp-spectrum-waterfall.jpg?242|2Msps 90MHz osmocom_fft -F}}]
  
 [{{:mission:log:2014:08:08:fm-broadcast-band-960k-90m-center-fftp-spectrum-waterfall.jpg?345|960ksps 90MHz DARC-Hunter.grc}}] [{{:mission:log:2014:08:08:fm-broadcast-band-960k-90m-center-fftp-spectrum-waterfall.jpg?345|960ksps 90MHz DARC-Hunter.grc}}]
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 **This looks fancy, but I don't know how to interpret it...** **This looks fancy, but I don't know how to interpret it...**
  
-The spectrum chart shows what's going on right now, the waterfall gives you the same information, but as a sequence of spectrum chart slices stacked together over a period of time and observed from the top, which is an invaluable tool to actually watch and observe frequency ranges and modulations.+The spectrum chart (left top/right bottom) shows what's going on right now, the waterfall (left bottom/right top) gives you the same information, but is a sequence of spectrum charts stacked together and observed from the top as 3 dimensional chart, showing time (y), frequency (x) and signal strength (z), which is an invaluable tool to actually watch and observe frequency ranges and modulations over a period of time, to recognize patterns visually.
  
 It's also interesting to note, how the spectrum of B5 on 90.0 MHz is clearly distinguishable from the other broadcasting stations in the RF baseband. There seem to be two signals 76 kHz left and right from 90.0 MHz   It's also interesting to note, how the spectrum of B5 on 90.0 MHz is clearly distinguishable from the other broadcasting stations in the RF baseband. There seem to be two signals 76 kHz left and right from 90.0 MHz  
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 **Stereo Difference Signal** **Stereo Difference Signal**
  
-The stereo difference signal (L−R) is modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz. A 19 kHz pilot tone, at exactly half the 38 kHz sub-carrier frequency and with a precise phase relationship to it, is also generated. This is transmitted at 8–10% of overall modulation level and used by the receiver to regenerate the 38 kHz sub-carrier with the correct phase.+The stereo difference signal (L−R) is modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz. 
  
 **RDS** **RDS**
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 <WRAP round download> <WRAP round download>
 **Download DARC-Hunter.grc File:**\\ **Download DARC-Hunter.grc File:**\\
-coming after cleanup+[[https://apollo.open-resource.org/downloads/darc-hunter-mk5.grc|darc-hunter-mk5.grc]]
 </WRAP> </WRAP>
 ==== Negative reference stereo FM station ==== ==== Negative reference stereo FM station ====
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 ===== Updates ===== ===== Updates =====
  
-[[https://github.com/muccc/darc|DARC GNU Radio Block Implementation]] by chris007 & andz - presented at [[https://eh15.easterhegg.eu/frab/en/eh15/public/events/2|EH2015]]+  * [[https://github.com/muccc/darc|DARC GNU Radio Block Implementation]] by chris007 & andz - presented at [[https://eh15.easterhegg.eu/frab/en/eh15/public/events/2|EH2015]] 
 +  * [[mission:log:2016:04:12:the-darc-knight-rises]] 
 + 
 +==== 2018-03-15 ==== 
 + 
 +Another DARC carrier has been found in Bremen on 88.3MHz: 
 + 
 +http://radioforum.foren.mysnip.de/read.php?8773,1457751,1458555#msg-1458555
  
 {{tag>darc rf sdr rtl-sdr hackrf gnuradio grc bus tram software hacking munich mvg research radio antenna}} {{tag>darc rf sdr rtl-sdr hackrf gnuradio grc bus tram software hacking munich mvg research radio antenna}}