Sigmira is a Software Defined Radio (SDR)
application program that
runs on Windows. It operates with
with an external conventional receiver,
or SDR-RADIO.com networked
Sigmira offers wideband spectrographic, waterfall,
and phase plane displays.
It also demodulates various military, utility,
and "ham" radio signals.
Sigmira's features include:
"Waterfall" and spectrograph displays of up to 200 kHz width with
Display up to 2 MHz width with the RTL-SDR.
Demodulation of HFDL, PSK31,
CW, and NFM modes.
Demodulation of NATO
Demodulation of the
"Japanese Navy Slot Machine"
Point and click signal selection/tuning.
with automated tuning and logging.
Phase plane display.
Playback of saved .wav files.
16 bit sampling. Typical sampling rate: 48 ksps.
Signal strength meter.
RF gain control.
Clock display with UTC and local time.
The distribution package includes examples of
HFDL, PSK31, RTTY, FSK, SITOR-B, CW, NFM, JSM,
and STANAG 4285 signals in .wav files.
A database of over two thousand signals is also included in
the distribution package.
And it's free.
Sigmira has been combined with XDFilt in the "sigtools"
A new version of Sigmira is available.
It supports the SDRplay RSP.
The new version is version 1r10.
It is contained in the sigtools_1r14_installer.
The download link is above.
New version supports SDRplay RSP.
Sigmira's maximum spectrum display width is still 2 MHz for now.
The Mirics chipset ADCs in the SDRplay RSP
have more offset and noise around DC.
For that reason I recommend that Sigmira typically
be run with the "DC Comp" feature turned on.
You may need to switch it off when AM modulation
is selected and you are tuned right on the carrier.
(One way to avoid the ADC offset is to tune to the
side of the signal, click "Lock Center", and then
tune to the signal.)
In the AM broadcast band I typically run with the gain at about
one quarter on the RF Gain control scale.
In quieter areas of the spectrum I run with the RF gain
set at about the midpoint.
If the gain is too high there will be
intermodulation of the signals and more artifacts.
If you see that back the gain down.
Also, if the plot in the Phase Plane display appears
to have a clipped, square outer boundary then reduce the
Sigmira_1r10 is included in Sigtools_1r14.
The new version can be installed without removing the
The desktop shortcuts will point to the last one installed.
If you remove the older version and have edited or customized
your signal database be sure
to make a backup copy of your "sigmira.sdb" file before
removing the old version.
To report bugs please send email to the
address given on the 'contact' page:
Sigmira is a trademark of Steven A. Harlow.