RTLSDR
RTL SDRs are one of the cheapest and most generic USB 2.0 Software Defined Radio (SDR) devices on the market while not enough sampling for video has become quite useful for HiFi decoding and calibration.
RF Connector Adapters BNC Male to SMA Male Aliexpress Link
Pictured Order: TNC Male to SMA Male / TNC Female to SMA Male / BNC Male to SMA Male / BNC Female to SMA Male / Nooelec RTL-SDR v5
These 2 GNU Radio Scripts (NTSC/PAL) will automatically connect to the RTL-SDR and use it as an RF input.
-
Real-Time Playback
-
FLAC 24-bit 48khz
-
8msps 8-bit Unsinged (.u8)
This GNU Radio script is capable of real-time sound playback alongside decoding to a 24-bit 48khz FLAC file and outputting an FM 8msps 8-bit u8 file.
This allows for fine adjusting of HiFi FM tracking before doing a full capture with a CX Card or DdD for example.
The RTL SDR (and clones) will show up as "Bulk-In, Interface (Interface 0)
Simply select the device, then click install WinUSB.
Install GNU Radio Linux / Windows
Connect an RTLSDR to the HiFi Test Point on your VCR.
Simply run GNU radio companion then file --> Open --> Select the NTSC/PAL Script
F6 Will Export the script to a python .py file.
F6 Will run the script.
F7 Will stop the script.
The FM RF output is defined by the File Sink
The FLAC audio output is defined by the Wav File Sink
You need to set the output location, to do this double click on a module and set the location you wish to save your files to, be sure to name them differently each time or the script will overwrite the previous file.
There are 2 standard .grc GNU radio scripts are provided below.
RTLSDR HiFi NTSC/PAL Low Overhead Download - Capture Only (8.192msps)
The max sample rate of the RTLSDR is 3.2 MSPS I/Q or 3.2 MHz of total bandwidth.
You can change this with the sample_rate module. (Bottom Left)
RTL-SDR Rates In GNU Radio
250000.000000, 1024000.000000, 1536000.000000, 1792000.000000, 1920000.000000,
2048000.000000, 2160000.000000, 2560000.000000, 2880000.000000, 3200000.000000.
3 sample rates work with the script before it starts skipping (Tested on Ryzen 5800x)
1 MSPS = 1024000.000000
1.5 MSPS = 1536000.000000
1.9 MSPS = 1920000.000000
Adam R for creating these scripts and Tony Andersan for R&D.