Trunk Recorder is able to record the calls on trunked and conventional radio systems. It uses 1 or more Software Defined Radios (SDRs) to do this. The SDRs capture large swathes of RF and then use software to process what was received. GNURadio is used to do this processing because it provides lots of convenient RF blocks that can be pieced together to allow for complex RF processing. The libraries from the amazing OP25 project are used for a lot of the P25 functionality. Multiple radio systems can be recorded at the same time.
Trunk Recorder currently supports the following:
Radio equipment dealer. Personal and business-related radio equipment for sale, new. Also, shortwave receivers, scanners, software-defined radios, radio accessories and stuff for kids.
rtl_power_fftw is a program that obtains a power spectrum from RTL devices using the FFTW library to do FFT.
It is inspired by the program rtl_power in librtlsdr. However, the said program has several deficiencies that limit its usage in demanding environments, such as radio astronomy. An inspection of rtl_power in hope of modifying it and obtaining better performance resulted in the conclusion that it would be an infeasible task. Measurements of FFT performance showed that the leading library in the field of FFT - fftw - makes mincemeat of the routine used in rtl_power, even on simple processors such as raspberryPi.
The website of an international group of numbers stations enthusiasts. Has a forum, a blog, a podcast (good luck finding the RSS feed), live streams...
This is a site that aims to collect and sort out information about some of the more unusual shortwave anomalies, like UVB-76, the more powerful numbers stations, the XM Whales, and other mysteries. Seems pretty solid, without much in the way of conspiracy, just necessary speculation.
A voice inversion descrambler (and scrambler). Can invert live signals in realtime. Has commonly used inversion carriers as presets.