Jump to: navigation, search

This page provides usage information on the various components of the W1HQ Remote Receiver (RRX) system.


afxmit takes no arguments. It does output some debugging information which can be piped to /dev/null in normal operation.


afrecv has the following parameters. All are optional except the host IP name.

  • -c Codec number (0 none or 1 Speex, default 0)
  • -p Port number (default 14694)
  • -b Speex buffering factor (default 4)
  • -e Speex "perceptual enhancement" (default 0)
  • -q Speex quality (default 8)
  • -x Speex complexity (default 3)
  • -s allow stop on keyboard interrupt? (default false)
  • -k stream kill only (default false)
  • host_ip_name

A typical afrecv command would be

     afrecv -c1 -b4 -e0 -q8 -x3

which, given the defaults, is the same as

     afrecv -c1

Most Speex parameters are discussed in Speex documentation. The values range from 1 to 10, generally. Increasing quality and complexity provides better fidelity at the expense of more network bandwidth and/or heavier Beagleboard CPU load. The defaults seem to be a reasonable balance for typical ham operation.

The buffering factor sets how many small Speex compressed output packets are sent together in a single UDP transfer. Speex operates on 20 msec audio "chunks", reducing them to 38 bytes typically. Thus a single UDP packet corresponds to 80 msec.

In uncompressed mode, an audio chunk is taken every 32 msec and sent as a single UDP packet.

remote requires no command line parameters. Many configuration variables are set up in the Python text.