A new SDR# driver for the RTL-SDR that comes with manual settings for the LNA/Mixer and VGA gain stages as well as software decimation (in Russian use Google Translate) has been released on rtl-sdr.ru. The three seperate gain stages offer much greater control over optimization of signal SNR and interference management. The decimation feature allows you to sacrifice some bandwidth for increased ADC bit resolution. This means that using the decimation feature can significantly improve the SNR of a signal. Update: It turns out that decimation is already used in the existing SDR# code, so using decimation in the new driver won’t improve the real SNR, only the visible SNR – so there will be no audible improvement. It will however allow you to effectively zoom in on the spectrum without loosing visible resolution. Also it allows you to use a higher sample rate (2.8 MSPS) which will improve SNR, whilst maintaining a reasonably sized (small enough) visible bandwidth for narrowband signals.
The driver is based on Oliver Jowet’s modified driver so it should also have the capability to tune down to 13 MHz or lower. To use the plugin simply download the zip file and copy the files into the SDR# folder, replacing all existing files. Previously we posted about another driver with similar capabilities, but this driver was never released to the public. There was also another driver with just the three gain settings released earlier which this driver appears to be based on.