VHF/UHF Digital Voice Software Modem

On Air Samples

Sample transmission (WAV File)


Voice audio, received on VHF (Speex) (WAV File)

Voice audio, received on VHF transmission (Codec2) (WAV File)

Note Please keep in mind with the above samples that that Codec2 is in early testing (alpha testing) and that the mode of Speex used in this modem (8000 bits/second compared to Codec2's 2550 bits/second) uses more than three times the bandwidth of Codec2. Codec2 quality exceeds Speex quality when using a similar bandwidth. In the future the spare bandwidth in the Codec2 mode may be used either for a robust mode (that could survive long dropouts with no interuption to the voice audio, at the cost of large latencies) or in a narrower bandwidth mode that would be suitable for radios with poor channel characteristics.