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 DF9CY - DRM Experimental Logfile

Christoph Petermann DF9CY 2004

Last Revision: 22 March 2004

DRM Log

22 March 2004

I continue receiving DRM with success. I have made some further work on my wideband receiver for DRM.

22 January 2004

My company got interested in DRM now. We purchased a simple crystal controlled receiver, which has remarkably performance. (www.broadcastpartners.nl/drm)

A small review is here:

We ordered the receiver board from Broadcast Partners some days
before last Christmas. It arrived now after about four weeks. I have
built it into a box and added BNC sockets for antenna, external oscillator,
RSSI, 10,7 MHz IF out and AF out.

Quality:
The pcb is good and no SMD components are used. Components seem to be
inserted and soldered manually with good quality.

Spec:
Supply Voltage: 15V .. 35V, but works from 10V.
Currents      : 90 mA measured.
Bandfilters   : (1) 150 kHz .. ca 2 MHz; (2) 5 .. 10 MHz; (3) 13 .. 17 MHz.
                No (2) is inserted and all other components are within the
                package.
Frequency     : I ordered RTL 6095 kHz
IF            : 10,7 MHz; 455 kHz and 12 kHz
ICs           : 3 * SA612 mixer; HEF4060 divider; 2 * TL072 OP
Oscillators   : all with crystals.
Sensitivity   : -3dBV for a signal peak of 20 dB above noise at 12 kHz -
                very good

Extensions:
I have added an external frequency source input and fed to one of the
crystal sockets. I need about 17 dBm for optimum drive.
Calculate 10,7 MHz + receive frequency = oscillator frequency
(i.e. 10,7 + 6,095 = 16,795 MHz).
I used a Rohde 6 Schwarz signal generator for testing, but a good source
will be the DDS generator you can buy from www.elv.de or Conrad Elektronik
(ca 70 Euro).

Performance:
The receive performance seem to very good with flat top filtering. Compared
to my RX320D it gives me about 1 dB advantage when signal received at the
same time from the same antenna. (I have made a so called magic-tee for
this purpose). The external signal generator allows me to receive any signal
in the given band. The RSSI output makes it easy to put the antenna to an
optimum position.

Further improvement:
I will make a switchable bandfilter which will allow a wider frequency
range to operate on.

Final:
Alltogether we paid 191 Euro for the receiver, as the price claimed excludes
VAT and transport. A lot of money. Nevertheless the board works very fine.
You cannot receive anything els, as there is no demodulator. BUT using a
Software Defined Radio (SDR) like http://www.sdradio.org/ you can receive
AM, CW, USB, LSB and FM in excellent quality. I am VERY pleased.

(written and published in www.drmrx.org forum) 22 january 2004

16 January 2004

Again some images from some receptions I made recently

05.01.2004 10.01.2004 15.01.2004
729 kHz DLF with dropouts

729 kHz DLF over 26 hours
note the nighttime
disturbances
1296 kHz BBC World Service
with selective fading
Spectrum Waterfall Display

Receptions made with DReaM 1.0


18 December 2003

I compiled DReaM 1.00. Thanks to the programmers around Volker Fischer for this outstanding software. It seem to run flawlessly.

I also have installed the latest FhG Software Radio 2.0.34, which also is a great work. My first Magnetic Antenna for Medium Wave is ready. The gain seems a little bit high and overdriving my receiver.


September to December 2003

Worked on my DRM Demonstration Receiver which already does work quite well. I changed IF frequency from 30,2 MHz down to 10,7 MHz.

Tried DRM mobile in my car. This was a strange experience. When driving an underpass like a bridge, the dropout came when I had passed that place already by a few seconds. Nevertheless it worked.

I am able to compile the free software DReaM by myself now. I did not get it working on a LINUX based system so far.

There were some more experiments with active antennas, but I could not significantly improve reception over my current antenna (9m Vertical).


31 August 2003

Some images from the software radio:

DRM Screenshots 30 August 2003
177 kHz Longwave
DRM and Analog AM in Simulcast Mode
Berlin/Oranienburg
Offset / No decode
729 kHz Mediumwave
DRM Deutschlandfunk
Often strong
Offset / No decode
1296 kHz Mediumwave
DRM BBC
England
Offset / No decode

Here is 729 kHz Deutschlandfunk with DREAM and also decoded sometimes:

DReaM often crashes; it does not seem to be very stable. I have it running under Windows ME.


18 August 2003

Here is a print of the reception log:

Date        Time   Freq   ID                Cntry Rpt1   Rpt2

8/4/2003    1438   5975   T-Systems         DL   19dB
8/4/2003    1439   6095   RTL               LX   18dB
8/4/2003    1441   7320   BBCWS             G    +15 dB  No decoding
8/4/2003    1443   13605  IBB Morocco       CN   +10dB   15dB QSB
8/4/2003    1445   15780  VoR               UA3  12 dB   20 dB
8/9/2003    1452   729    Deutschlandfunk   DL   53      No decode, as I have offset of 1 kHz
8/9/2003    1817   6140   DW                DL   +22dB
8/9/2003    1457   7320   BBCWS             G    23dB
8/9/2003    1455   13605                    CN   10 dB
8/12/2003   1919   729    DLF Putbus/Rgen  DL   min 15 dB   no decode   Offset
8/12/2003   1917   855    DLR Berlin/Berlin DL   ca 10 dB   Data
8/12/2003   1913   1485   DasDing SWR       DL   low weak
8/13/2003   1912   531    531 digital       DL   ca 10 dB no decode
8/13/2003   1910   855    DLR               DL   peak 12.7 dB
8/13/2003   1858   1485   SWR Das Ding      DL   7 dB    data decode
8/13/2003   1640   6140   DW                DL   +20dB   qsb
8/13/2003   1641   15780  VoR               UA3  18+dB   qsb
8/16/2003   1631   6140   DW                DL   +24 dB
8/17/2003   1035   6140   DW                DL   23 db
8/17/2003   1039   7320   BBC WS            G    22 db
8/17/2003   1040   9615   RNW               NL   9 db
8/17/2003   1041   13755  VoA               CN
8/17/2003   1043   15440  DW WS             CT1  DL   25 db
8/17/2003   1044   25765  TDF               F    10 dB



15 August 2003

My Demonstration Receiver works and I could receive the first DRM signals. A fine success.


30 July 2003

I installed the Software Radio and received the keyfile. It took only minutes to get the thing running. I immediately received the first DRM signals:

30.07.2003 18.25 UT 6140 kHz Deutsche Welle Good Quality but getting weaker due to conditions changing
30.07.2003 19.15 UT 9855 kHz IBB Morocco Very good signal for more than 1 hour; no drops at all

28 July 2003

The TenTec RX320D receiver arrived finally after 6 weeks. It works fine.

Middle of July 2003

The plan for the demonstration receiver is made and all parts are here. First stages running.

Middle of June 2003

Made plans for a simple demonstration receiver and ordered the TenTec RX320D

The vertical antenna for reception and amateur radio transmitting is up.

End of May 2003

First impression of DRM in Eindhoven/NL

Text and All Images are Copyright by Christoph Petermann DF9CY

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