Using Spectrum Lab with SDR-IQ / SDR-14


To use Spectrum Lab with SDR-IQ or SDR-14 (Software Defined Radios by RFSPACE), you will need the USB Serial Drivers by FTDI installed on your system, or a TCP/IP connection to a remote "SDR server" (USB-TCP/IP gateway). But if you have an SDR-IQ or SDR-14 connected to your PC, you will most likely already have the program SpectraVue (by MoeTronix) installed. In that case, the FTDI drivers are already installed, and Spectrum Lab can talk "directly" to the radio (it doesn't require any ActiveX control to work). Since the USB connection to the radio can only be occupied by ONE application at a time, it is impossible to have Spectrum Lab and SpectraVue running side-by-side.

SDR-IQ or SDR-14 directly connected to the local PC via USB / FTDI driver :

If SpectraVue has not been installed on your system, you need to install the FTDI drivers. Search the net for "FTDI D2XX drivers", which should take you to a download site at Look for the "setup executable" (it's easier to install than the zipped archive, which lacks any "setup"-feature). When tested with Windows XP and the FTDI D2XX driver, the LEDs on the SDR-IQ were immediately turned on after the driver was installed, and Spectrum Lab could communicate with the radio (see next paragraph). There is almost no documentation on the FTDI site how to install or supervise the D2XX driver, so here's how and where to find it in the windows (XP) system control:

Besides FTDI's USB driver (*.sys, located in some windows system directory), the "setup executable" by FTDI will also copy an interface DLL into a window system directory (under Win XP, c:\WINDOWS\system32\ftd2xx.dll). Spectrum lab will try to load this DLL dynamically if necessary.

To let Spectrum Lab talk to the SDR-IQ "directly" (via USB), uncheck the "remote" option on the SDR Control/Configuration panel (see below).

SDR-IQ or SDR-14 connected via TCP/IP (LAN) to a remote server :

As an alternative to connecting Spectrum Lab "directly" to the radio (via USB), you can use a TCP/IP connection for remote operation. To do this, check the "remote" option on the SDR Control/Configuration panel (see next chapter), and enter the IP address and port number in the edit field next to the checkmark. If you are using MoeTronix's "SDRxxServer.exe", the default port will be 50000. If the server runs on the same PC as Spectrum Lab (for a "local test"), use the IP address .

To select SDR-IQ or SDR-14 for input (instead of the soundcard), open the "audio settings" tab in SL's configuration, and select "SDR-IQ / SDR-14" in the list of "Audio Input Devices".
Note: SL doesn't check if the radio is really connected to the USB port in advance !

Alternatively, to check if the installation was ok, select Quick Settings..Image cancelling DC receivers (I/Q).."SDR-IQ, 37 kHz sampling, downconverter, 3 kHz audio bandwidth" in SpecLab's main menu. In this configuration, SL acts as a back-end for a software defined radio, including waterfall display and audio output (through the soundcard). How to set the receiver frequency is explained in the next chapters of this document. How to adjust the audio filter is explained in another document.

SDR Control / Configuration Panel

To open the following control panel for the SDR-IQ / SDR-14, select View/Windows / SDR-IQ Control Panel in SL's main menu:

SDR VFO tab / main control panel

screenshot SDR-IQ control panel

You can modify the radio's NCO (numeric controlled oscillator) in the "VFO" field. Either type the number, or click on one of the digits to place the cursor there. You can then increment / decrement the frequency with the cursor up/down keys, or with the mouse wheel (unlike SpectraVue, just pointing the mouse above the edit field isn't sufficient ! ).
The RF gain combo changes the preamp gain / attenuator (AD8370), the IF gain combo sets the digital IF gain (AD6620 in the SDR-IQ). Some less frequently used settings (which are specific to the SDR-IQ and SDR-14) must be set on the "cfg"-tab (config):

SDR Config tab

The radio's IF bandwidth (and, at the same time, the sampling rate) can be set on the "CFG" (config) tab of this control panel :

SDR-IQ config tab


Other options on the SDR configuration tab are:

Because the sampling rates of the SDR-IQ are not integer multiples of the soundcard's standard sampling rates (like 11025, 22050, or 44100 Hz), you need Spectrum Lab's output resampling function if you want to send the (demodulated) signal to the audio output of the soundcard.

Remote Control for SpectraVue

For some special applications, Spectrum Lab can send control commands to SpectraVue through the registered messages mentioned in the SpectraVue manual.
At the moments, the following commands can be used (copied from ..command_files\testcmd.txt ). Of course, it makes more sense to use these commands in the conditional or scheduled actions.

; SpectraVue Control ..
svc.fc=12345678     // send center frequency in HERTZ
svc.fs=100000       // send center frequency in HERTZ
svc.start           // start SpectraVue
svc.pause           // pause running (how to restart?)
svc.stop            // stop running (-> SpectraVue "idle")
svc.fcapture=0      // file capture (in SpectraVue) OFF
svc.fcapture=1      // capture RF in file
svc.fcapture=2      // capture DEMODULATED output in file
svc.rfgain=0        // set RF gain (0..3; no effect?)
svc.ifgain=0        // set IF gain (0..4; 0=max)
print "SpectraVue: fc=",svc.fc,"Hz"," fs=",svc.fs,"Hz"

See also:
  Selecting an Audio Input Device in Spectrum Lab (SDR, soundcard, or similar hardware)
  Audio via COM port (serial port, from external A/D converter)
  Using Spectrum Lab with Perseus
  Using Spectrum Lab with FiFi-SDR
  Using Spectrum Lab with a Winrad-compatible ExtIO-DLL for input