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Digital Radio Mondiale aka DRM on your PC
This is what you need to receive DRM broadcasts on Medium and Short Wave:
If possible use an outdoor Antenna A good Receiver with an Output Terminal for the IF Frequency A Down Mixer to generate the necessary 12 kHz signal output A Personal Computer with DRM Software installed A Sound Card with a free Line or Microphone Input A pair of Stereo Speakers
USEFUL HINTS To achieve the best results, be sure to think about the following:
Keep the ground of the receiver and computer apart. Use a transformer in the 12 kHz feed to the PC. A switched Power Supply can be a source of severe disturbance. Always run the power supply connected to an AC socket with earth. Small power supplies with a diode bridge inside can be a source of buzzing noise too. If you can, open them and connect 0.01 uF across each of the two or four diodes. Try to connect the receiver to ground if possible. Stay well away from ADSL modems and electronic dimmers
DRM Down-Converter For 455kHz IF Receivers
455 Khz to 12 KHz converter
DRM Down-Converter For 455kHz IF Receivers Posted Apr 22, 2013 at 9:47 am This project came about due to my interest in a new form of radio transmission called DRM, which stands for “Digital Radio Mondiale” (see). This is a new form of digital shortwave transmission. A few devices are available from Europe for decoding the digital signals but are expensive. I decided instead to modify an existing circuit, using a stable purpose-built 470kHz ceramic resonator as the oscillator, rather than the original unstable L/C version. The 455kHz IF signal from a shortwave receiver is fed into the input (pin 1) of a double-balanced mixer and oscillator (IC1) via a level adjustment pot (VR1). The NE506’s output (pin 4) is then AC-coupled to a PC’s sound card input for processing. With the capacitor between pins 5 & 7 set to 150pF, the oscillator frequency should be around 467.5kHz. You can check if the oscillator is working by putting it near a receiver tuned to 467kHz. You should hear a beat frequency. DRM DownConverter Circuit Diagram For 455kHz IF Receivers
DRM DownConverter Circuit Diagram For 455kHz IF Receivers
The IF signal of 455kHz is mixed with 467kHz, giving an output with a centre frequency of 12kHz. Sound cards should have no trouble sampling the 10kHz-wide DRM signal. A number of software-defined radio applications were found to work well with this converter. These applications perform all of the demodulation (SSB, AM, FM, etc) and various other DSP functions. If all is well, connect your 455kHz IF to the input and your computer sound card to the output. Run the Dream software (see), and tune to 6095Khz (RNZI), or 1440Khz (SBS). You should see the Dream software lock onto the DRM transmission and audio should start playing from the computer speakers. The NE602AN mixer/oscillator and 470kHz resonator are available for a cost of $12.50 – email the author for more details at .(JavaScript must be enabled to view this email address). A CD with various software defined receivers as well as the latest Dream software decoder is also available.
The USB Dongle RTL2832 including its plastic housing is 85 mm long, 27 mm wide and about 14 mm high. I bought it in Internet from Superbat Electronics in April 2014 for USD 11.- including shipping from Hong Kong. Also included in the price was a remote control with a battery and a software for watching TV (which I have not used). There was a small antenna with a connector included in the shipment. The first one I bought cost slightly more, had no antenna but instead I got an adapter that fits TV or cable TV connectors.
The USB Dongle RTL2832, USD 10.00 Fig. 1 The USB Dongle RTL2832
I had heard somewhere that it should be possible to use this receiver for short wave without an up-mixer and decided to give it a try. I took my RTL USB dongle apart and located the pins 1 and 2 on the RTL2832U.
Some tests with the USB Dongle RTL2832
Fig. 2
In my version those two pins were fitted with coupling capacitors marked C33 and C34. Connecting an antenna to pin 1 did not produce any results at all. Then I removed C34 and connected my active antenna via a 0.022 uF capacitor in series.
Back to top
Fig. 3
With the SDRSharp v1.0.0.163 (which is available free on the Web) set to Direct sampling (I branch) I could listen to KBC Radio on 6095 kHz in AM with quite good results around noon in August in Sweden. At least some sound.
Going for DRM with this 10 USD Receiver
In order to use the RTL2832U dongle with the SDR Sharp it is necessary to install the Zadig software. It will uninstall the drivers installed by the CD that came with the RTL2832U and install the necessary drivers to connect to the SDR Sharp. Then, to use the Dream software with the SDR Sharp it is also necessary to install an additional driver, a "Virtual Audio Cable". I use the "VB-CABLE" which turned out to work well. With the RTL2832 Dongle in its USB port and the SDR Sharp and Dream running on the computer it is time to set up the parameters for DRM reception.
The SDR Sharp Main window
Fig. 4
Change the parameters in the SDR Sharp as follows:
Select "RTL-SDR / USB" from the drop-down list Check the "USB" radio button Type "13000" in the field Filter Bandwidth box Type "500" in the field Filter Order box Select 1 kHz Step size I checked the "Snap to grid" check box Check the box "AGC" Select the Virtual Audio Cable as AF output from SDR Sharp (not seen in this picture)
Press the "Configure" butto in the SDR Sharp and a new window opens:
The SDR Sharp Configuration window
Fig. 5
Change the default parameters in the SDR Sharp as follows:
Select "Generic RTL2832U OEM" from the drop-down list Set the Sample Rate to 2.4 MSPS from the drop-down list Select "Direct Sampling (I-branch)" from the Sampling Mode drop-down list Check the box "RTL AGC"
Close this window.
Tune the SDR Sharp to a DRM transmitter. In Fig. 4 the receiver is set to BBC on 3955 kHz. The tuned frequency should be set to 6 kHz below the wanted frequency, in this case 3949 kHz.
Start Dream and select the proper Audio Input
Fig. 6
Under "Settings" in Dream, select "Sound Card Selection - Sound In - VB Audio Point". The output should be set to the normal audio to get the decoded audio to the PC loudspeakers.
The Dream Evaluation window
Fig. 7
There are no special settings to change in the Dream Evaluation window. Use the volume control in the SDR Sharp to adjust the input audio to Dream if it is too little or to loud.
Reception of the BBC on 3955 kHz
Fig. 8
At least DRM reception is possible with this basic attempt using a simple antenna and the RTL 2832U Dongle.
More to follow later: An improved antenna connection to the RTL Dongle and some added pre-selection for the different frequency bands.
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Toate Stick-urile SDR cu Realtek sunt relativ "surde". E mai mult un chin sa iei fara upconverter DRM-ul, cu driverul "no hardware mod" Trebuie si o antena foarte buna, degajata, ca sa receptioneze ce intra pe un portabil DRM cu telescopica lui. O solutie este fie upconvertor fie modificarea hard
La cel cu R820T este si mai simplu, se conecteaza direct pe pinii 4 si 5 si se comuta pe intrarea respectiva din soft (Q)
Singura problema, deloc mica daca nu ai scule dedicate, este lipirea firelor direct pe pinii 4 si 5 datorita dimensiunilor extrem de reduse ale chip-ului respectiv.
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marsel90
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Zgomotul este foarte mare in banda de unde scurte.Fara un acord al antenei nu prea poti face mare lucru cu un sdr.
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Trebuie si filtru
si o antena degajata ( ca sa mai vada vecinii inca ceva fire intinse pe bloc eventual care sa si suiere la vant )
Pentru benzile de radiodifuziune merge sa lungesti un pic prima varianta @ 30m + 15m Dar.... Multa munca pt. 3 lulele de DRM-uri, un sistem la care au renuntat mai toti producatorii de echipamente de receptie. Numeri pe degete cate radiouri cu DRM sunt pe piata in toata lumea. Chiar si cei care au tehnologia necesara la emisie o folosesc partial si doar cand target-ul e considerat a avea o receptie relativ stabila. Cand scade semnalul de la fading sub prag nu se mai aude deloc, cu tot buffering-ul lu' peste prajit pe care-l face DRM-ul pt. compensare.
In ultima vreme pe unde scurte interesul a scazut in mod constant, au ramas destul de putini radio - broadcasteri. Aici....CHINA rules. Mult asteptata relansare a interesului pt. SW cu DRM-ul s-a dovedit pana acum un "eshec". ( singularul de la eshece )
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marsel90
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Sunt de acord cu dumneata, dar am vrut sa pun stick-ul la munca sa incerc si altceva.Daca tot mai exista transmisiile astea drm eram curios cum se aude un digital transmis pe unde scurte.Nimic nu se face imediat si usor, te lovesti de tot felul de probleme, zgomot, interferente, intermodulatii s.a.m.d. Sa pot receptiona acele drm-uri nu am fost posibil decat trecand antena printr-un acord sau "transmatch".
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Radio Romania International
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007/Ro
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Nu se aude nimic ...
Programul DRM-ului RRI ( si nu numai ) se poate gasi pt. cei interesati aici
In functie de azimutul vizat la emisie, locatiile de emisie si receptie se receptioneaza mai bine sau mai rau in Romania.
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DRM RRI Tiganesti -> Receptie Bucuresti
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007/Ro
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Se observa ce sunetul este foarte Hi-Fi.....
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007/Ro
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Iaca si un sample....
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Costel DVB-T2
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Consultare publică în vederea organizării licitației privind alocarea spectrului radio pentru T-DAB (radiodifuziune digitală terestră în banda III VHF (canalele 11 și 12 de televiziune analogică.
Având în vedere că, până în prezent, piața nu a manifestat un interes cu privire la spectrul radio pentru T-DAB în banda III VHF, vom iniția o consultare publică cu scopul de a evalua interesul pieței și necesitatea organizării acestei licitații.
Trim. III 2015 ANCOM
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Te-a pasionat DAB-ul din Bucuresti pana acum?
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Costel DVB-T2
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Admin a scris:
Te-a pasionat DAB-ul din Bucuresti pana acum?
Doar Polaris-ul si ...pe viitor , 5-10 dvb-t !
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BBC (DRM) ID: E1C249 @ 5845 KHz from Nakhon Sawan - Thailand in Bucharest 7542 Km ( no label, only ID )
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BBC (DRM) ID: E1C238 @ 5845 KHz from Nakhon Sawan - Thailand in Bucharest 7542 Km
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)
)
în banda III VHF (canalele 11 și 12 de
