sonifex pc fm

The FM Radcap PCIe is a radio capture card designed for simultaneous recording of multiple radio stations. The frequency of each station is set in software and its audio appears as a standard Windows audio input device. RDS decoding is also supported.

The card uses a high-speed A/D converter to digitise the entire FM band, with up to 32 individual tuners. The Radcap achieves exceptionally low audio distortion through the use of linear phase filtering and mathematically precise FM demodulation and stereo decoding. FM demodulation and stereo decoding is done in FPGA fabric, while RDS decoding, if enabled, is performed in the driver using the host CPU’s SSE-2 instruction set. This division of labour between the FPGA and driver allows greatest flexibility in catering for future baseband technologies while minimising the CPU overhead of the card.

A WDM driver for Windows XP (SP2 or later), Server 2003, Vista, Server 2008, Windows 7, Server 2008 R2, Windows 8, Server 2012 & Windows 10 and Server 2016 is supplied as well as software for setting the tuner frequencies and monitoring the received audio. A programming API and DLL for software control and monitoring are also supplied.

The card can be configured to operate in stereo, mono or paired mono (two mono stations combined on a 2-channel audio stream) modes. Multiple cards can be used in a single PC, subject to available CPU bandwidth. The audio de-emphasis may also be set to either 50us or 75us. In Australia, New Zealand and Europe 50us is used, while in the USA and Canada 75us is used.

A utility called FMSpectrum is supplied. This displays the RF spectrum from 85MHz to 111MHz, using data from the card’s front-end 256-point FFT and may be useful in selecting the best location for the antenna or resolving interference problems.

The card is factory-configured for 6 (PC-FM), 12, 18, 24 or 32 (PC-FM32) stations, but may be expanded in the field for an additional charge.

Operating Systems Supported

Platform:Windows XP (SP2 or later), Server 2003, Vista, Server 2008, Windows 7, Server 2008 R2, Windows 8, Server 2012, Windows 10 & Server 2016 (32-bit and 64-bit versions), Windows Server 2019
Processor:2.5GHz Pentium 4 or better
Memory:256 MB minimum (1GB for Vista Windows 7/Server 2008, 2GB for Windows 8, Server 2012, Windows 10, Server 2016)
Bus:Single lane PCI Express v1.1
Other:Sound card or motherboard sound port for monitoring


Tuning Range:87.5MHz to 108.5MHz in 25kHz steps
Sensitivity:10uV for 40dB S/N
Maximum Input:150mV RMS
RF Input Impedance:75Ω
De-emphasis:Configurable as 50us or 75us
Audio Distortion:<0.01%
Audio Sampling Rate:48kHz (all other rates automatically supported via Windows sampling rate converter)
Number of Stations:6, 12, 18, 24 or 32 (factory configured but end-user expandable)
RDS Decoding:Optionally enabled in driver configuration

Equipment Type

PC-FM6 Channel FM PCIe Radio Capture Card
PC-FM1212 Channel FM PCIe Radio Capture Card
PC-FM1818 Channel FM PCIe Radio Capture Card
PC-FM2424 Channel FM PCIe Radio Capture Card
PC-FM3232 Channel FM PCIe Radio Capture Card
PC-FMUP6Radcap FM 6 Channel Upgrade
PC-FMUP8Radcap FM 8 Channel Upgrade

Physical Specification

Dimensions (Raw):14cm (L) x 12.5cm (H) x 2cm (D) 5.5” (L) x 4.9” (H) x 0.8” (D)
Dimensions (Boxed):27cm (L) x 22.5cm (H) x 6cm (D) 10.6” (L) x 8.9” (H) x 2.4” (D)
Weight:Nett: 0.10kg Gross: 0.20kg Nett: 0.2lbs  Gross: 0.4lbs
BW Price Guarantee

(Subject to conditions)


Tech Support

2-Year Warranty


Related products
STUDIO Receivers / Off-Air Monitors Sonifex PC-FM