DRM+ and DRM30 Modulator
Spark Pro (licenced) for Linux.
ETTUS USRP B100, shifts the complex baseband to RF band, (better than -55 dBc shoulder distance).
STO-2000 Transmitter (built by Lars Liljeryd), DRM OFDM 200 watts RMS (at -38 dBc shoulder), DRM OFDM 250 watts RMS (at -34 dBc shoulder), harmonics <-70 dBc, class A/B. No pre-correction or cavity filter needed!
Radio receiver, DRM+ demodulator
Wavesink software defined radio.
Radio front-end (simple)
Terratec NOXON USB-stick.
Elenos 3-element Yagi, center frequency 97 MHz, SWR <1.2. See VNA-plot below.
Radio front-end (advanced) FUNcube DonglePro+ USB-stick.
Radio receiver, DRM30 de-modulator
DReaM software defined radio.
Jeep Wrangler Sahara equipped with ground-plane vertical antenna for mobile testing.
Closeup of ground-plane vertical (SWR <1.2 at 97.0 MHz).
Reference measuring site 01
Approx 6 km from transmitter, useful for field-strength measurements, SNR-evaluations etc. SNR at this point is approx 24 dB for DRM+ 4-QAM (lower limit for this mode is approx 6 dB).
Hand held receiver for DRM+
Google Nexus 7 connected to vehicle stereo system and USB radio-stick.
Digital Radio Sweden
Test transmissions phase 1
Digital Radio Sweden started in February 2014 its first test transmissions with DRM. These are the first DRM+
broadcasts ever in Sweden. The test represents the start of the first phase of our test transmission series and
is designed primarily to enable a technical analysis of equipment used and compare and evaluate wave
propagation and related transmission modes and competing jammers amongst other technicalities. The
evaluation of the results is expected to provide a good basis for optimizing test transmissions for phase two.
In phase one, we use experimental, small-scale and cost-efficient equipment for evaluating the unique
modes we want to test as such modes are not possible to test or readily available using conventional
professional broadcast equipment. Furthermore, the current topographic antenna placement is not ideal,
however sufficiently useful for our technical evaluation. In phase two of the field trial we will likely use
professional broadcast equipment together with a topographically optimal antenna placement.
Transmitting antenna horizontal and vertical pattern
Elenos 3-element Yagi, placed on top of 6 meter mast, theoretical plots
A special thanks to the following persons:
Michael Feilen (Munich)
Lothar Stoltz (Munich)
Torbjörn Hammarström, Rohde & Schwarz Sverige AB (Stockholm)
Equipment - phase 1