Thanks to Carl's (N4PY) recent thread on the Dream software for DRM, I am
able to receive DRM broadcasts with my Pegasus. I modified the Pegasus to
bring out the 12 kHz IF out to the SPARE jack on the back of the Pegasus.
The details of the mod for the Jupiter are at:
http://kd4dcy.net/jupiter/mod_ifout/mod_ifout.shtml
But the Pegasus is identical, so the same mod works for it.
The Dream software is available for free download at:
http://home.t-online.de/home/sat-service/sat/DRM/DRM.htm
I ran a cable directly from the SPARE jack on the Pegasus to the line input
of my soundcard with no isolation or padding.
My computer hardware consisted of a 1.6 GHz Pentium IV running Windows XP
Pro. The soundcard is a Turtle Beach Santa Cruz, which is one of the more
popular ones with the FlexRadio SDR-1000 (a computer based SDR) users. They
are only about $50. I use the N4PY software to control the Pegasus, but any
control software would work. With the Jupiter, the front panel could be
used.
My antennas consist of a Carolina Windom 160 and a Force 12 XR-19 for 10,15
and 20. Ironically, I often get better copy on the antenna that does worse
for conventional AM SWL on the same band.
The Dream software didn't really require an installation, I just copied the
files to a folder on my PC and it ran. Since I actually have two soundcards
(the onboard one and the Santa Cruz) installed, I had to mess with
configuring which soundcard to use, but the Dream software has options for
that.
The Dream software even has a built in schedule of DRM broadcasts that can
be updated online, which includes an option to only list broadcasts that are
currently on the air.
Results:
When I got things hooked up, the only DRM broadcast that I felt I had a
chance of receiving was R. Kuwait. I tuned the Pegasus directly to the
indicated frequency. In less than a minute, I knew things were working as
"MOI Kuwait" was displayed on the Dream screen. Shortly thereafter, after
getting my computer speakers working, I had audio.
Yesterday morning, I tuned into China Radio Int'l (Taiwan) with a broadcast
aimed to Europe. There were a few dropouts, but for the most part it sounded
like FM, which is what is was as it was a relay of local FM, complete with
id's of "91.5 FM" The Dream display indicated that the broadcast was in
stereo and headphones confirmed that.
Last night, I tuned to a scheduled broadcast from R. Nederland in Bonaire.
However, what I got was audio from the BBC. For over 30 minutes I had FM
quality (sounded the same as the BBC does over our local PBS FM station)
without a single dropout. The Dream software has the capability of
recording a .WAV file and I recorded about 350 Megs worth. However, shortly
after I quit recording, the reception deterioated.
Also, last night, I was unable to lock on to R. Kuwait. I could get MOI
Kuwait on the display but no audio. The DRM signal was there but the
evaluation spectrum display in the Dream software showed a carrier near the
top end of the DRM signal. Sure enough there was a Spanish AM broadcast
there. The lower sideband was completely covered by the DRM, but the upper
sideband was clear and copyable (the Dream software has an AM/USB/LSB
receive option for analog signals).
On my 1.6 GHz Pentium IV, the processor load is about 30 - 40%.
All in all, it's been pretty interesting. I'd recommend giving it a try.
Hopefully over the weekend, I'm going to modify my Orion to bring out it's
IF signal (14 kHz) and see if that will work.
73,
Mark
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