RadioBanter - View Single Post

June 15th 06, 10:50 PM posted to rec.radio.shortwave

wrote:
So I could make a short wave radio out of a laptop
using this software?

You can make an Extremely Low Frequency radio out of a computer,
tunable across the bandwidth of its sound system. You could tune up to
about 1/2 the sampling frequency of the sound systems analog-to-digital
converter. Typical sample rates are 48kHz but high end systems go up to
192 kHz so the tuning range would be up to 24 kHz and 96 kHz
respectively, provided the computer can execute the SDR DSP software
fast enough. If you connected an antenna to the microphone input, you
might hear something. To tune higher frequencies, you can use a
conventional superhet receiver as a tunable downconverter, connecting
its last IF (if higher than the computer's audio input range) to a
fixed downconverter, e.g., from 455 kHz to 12 kHz.

Some radios, like the DX-394, can be readily modified to integrate the
fixed downconverter or attach it externally. And there are exceptional
radios that already include a 12 kHz IF output ready to be plugged into
the computer.

I have had great fun using the DX-394 with Dream and SDRadio software
demodulators. The performance on SW-AM broadcasts and SSB is truly
remarkable because of the steep-skirted IF filter and synchronous AM
demodulation.

Tom