DRM trial II in Sottens
Following the amateur radio DRM trial on the phased out shortwave antenna in Sottens in 2004, it has been decided to make another amateur radio DRM trial but this time on the 188m MW antenna that has just been phased out on 31.12.2010.
The tests will happen on 13th February 2011 and 20th February 2011 with 15 minutes periods on the following times (same for both sundays):
- 20h-20h15 CET (19h-19h15 UTC) TX on 7.180 MHz
- 21h-21h15 CET (20h-20h15 UTC) on 3.780 MHz
We will use the narrowest band so 4.5kHz and high robustness to transmit slides.
Please send your reception reports to firstname.lastname@example.org
Original audio loop transmitted
- Spark software (free full license gracefully offered by Michael Feilen)
- USRP with LFTX daughterboard
- Mini-circuits Gali74+ amplifier
- Preamplifier recycled from the bin from Asulab by Yves (HB9DTX)
- Amateur radio linear amplifier.
- 4.5kHz, Mode B, MSC 16QAM, EEP code rate 0.5, AAC audio at 4.8kbit/s
- 4.5kHz, Mode B, MSC 64QAM, EEP code rate 0.5, AAC Audio, MOT Slideshow at 2.56 kbits/s
See also: http://www.drmrx.org/forum/showthread.php?t=2307
Credits to Yves HB9DTX, Stan from Maxxima, the HB9MM amateur radio club and Swisscom for lending them for a month such a great antenna. At least Sottens will have gone digital before dying. It shows also that DRM transmission can be done with limited equipment (apart from antenna), an interesting thing for local or community radio. Mathias HB9UFQ
- HB9MM special operation in Sottens: http://www.hb9mm.com/sottens
- Receiver modification to catch DRM transmissions using Dream or Diorama or SODIRA or any other commercial software radio receiver.