Sudden ionospheric disturbance collector (sidc)

Note: This is the fork of the original sidc with various improvements and bugfixes.

1. Introduction

sidc is a simple C program to monitor and record VLF signal for sudden ionospheric disturbances. It is forked from sidd program wirrten by Paul Nicholson <sid0807@abelian.org> http://abelian.org/sid/

2. Installation

• First install FFTW3 dependency from www.fftw.org or use your favorite package manager to install fftw-devel package.
• Install alsa-lib-devel package if you want to use alsa (optional).

• Configure and compile the source

  autoconf

  ./configure

  make

• Install the source (if appliable)

  make install

• Edit sidc.conf to suit your requirements. Select an output policy from the three available.

• Start sidc in verbose foreground mode with the command

  ./sidc -vvf

• The program will output peak and rms readings in the range 0.0 to 1.0 Adjust your mixer gain settings to leave a little headroom on the peak reading.
• Plot the utility spectrum file
• Check the data file columns are the ones you want.
• Set your PC clock and activate your favourite time synchronisation software. Make sure it slews the clock rather than stepping the time.

• Restart sidc in background with

  ./sidc -v

• After a period of time, plot some of the data from the output file.
• After a midnight crossing, make sure sidc has switched to the next output file.

3. Command line options

There are just a few command line options - most controls are in the config file.

-v Be a little more verbose with log messages.

Use several -v for more detail.

-f Run in foreground. By default, sidc detaches from the process

group and terminal and becomes a daemon. In foreground mode, log messages are duplicated to stderr.

-c config_file Run with a specified config file. By default, sidc looks

for /etc/sidc.conf

-p pid_file Override default PID file location which is /var/run/sidc.pid.

Pid file is created everytime this process becomes a daemon. Creation is skipped if file is not writable.

4 Miscellaneous notes

• sidc will set the soundcard to the nearest available sample rate to that specified in sidc.conf
• 24 bit soundcards may return data in 32 bit words. Try setting 'bits 24' and if sidc reports the mode unavailable, use 'bits 32'.
• Make sure you have enough disk space. The example sidc.conf with 8 bands generates files of about 100Mbytes per day, which compress down to about 30Mbytes. Arrange scripts for plotting. Arrange scripts for compressing and archiving files that are a few days old.
• Simple init scripts provided. Check the readme in init_scripts directory.