Tagged: FL2k

Generating White Noise with an FL2K Dongle

The FL2K project allows us to turn a cheap USB 3.0 dongle into a fully transmit capable SDR (filters still required for high power work). We have posted about the FL2k project several times on this blog since early 2018.

Recently we thank reader Mikael for submitting a fork of the Osmo-FL2K driver code which he writes enables it to generate white noise with uniform amplitude distribution. This could be useful for projects that require a wideband noise source such as when attempting to measure filter and VSWR of antennas.

IK1XPV, author of the code notes that the current code is only tested on the Windows driver branch, via compilation on Visual Studio 2019 at the moment. The main contributed code can be found in \src\fl2k_noise.c.

FL2K Test Hardware
An FL2k Dongle connected to an RTL-SDR via VGA to BNC Breakout Cable and Attenuators

TV Scrambling With GNU Radio and a FL2K Adapter

[mrgriscomredux] over on [Reddit] was interested in re-creating the nostalgia that was scrambled analog television from the 90s. To do this he captured an NTSC analog video signal using an RSP1 SDR and demodulated that into composite video using GNU Radio to process everything.

The methods that were originally used to scramble analog television are not well documented, however [mrgriscomredux] has done a fine job re-creating it himself in his own way.

He then uses a Python script to modify the “Gated Sync Suppression” within GNU Radio and then transmits that back on to the air using a low cost FL2K VGA adapter we’ve featured on the blog in the past.

These FL2K VGA adapters can be abused as crude software-defined transmitters and we’ve seen people do everything from video transmission to GPS spoofing with them. [Check out the FL2K article here]

broadcasting my own scrambled tv channel with SDR