It is probably the cheapest way to get a
taste of Software Defined Radio and it's software. This 40m
design by KB9YIG uses a crystal oscillator, a divider and a
mixer to produce I and Q signals which are injected into
your sound card, so it basically is a direct conversion
receiver. Demodulation is done in software.
I have had a try using Quisk on linux. You get a nice
waterfall and spectrum display with selectable modes and
filters. In order to get things running the configuration
file needed a bit of tweaking. Create a file called .quisk_conf.py
in your home directory with the following entries:
import quisk_hardware_fixed as quisk_hardware
softrock_model = "fixed"
fixed_vfo_freq = 7056000
sample_rate = 96000
You might need to adjust the sample rate so it suits your
sound card. The higher the sample rate, the more of the 40m
band you will see.
Performance is amazing. Good selectivity and audio.
Using a full size 40 meter dipole seemed to be no
problem for the receiver.
Webshop of WB5RVZ
with several softrock kits
, a python based multi-platform SDR