gqrx-scan

Control GRQX to scan frequencies or from channels using a CSV file.

High level functionality

• Scan a range of frequencies with a specified mode (AM, FM, etc) or a csv file
• Monitor a single frequency or channel, pair with record etc to quickly record activity on a channel etc
• Exclude specific frequencies (birdies, interference, etc)
• Exclude specific channel names
• Scan a range of channels or a list of channels
• Scan a pattern of channels by name or frequency
• Resume scan from current frequency or channel

Signal Detection

• Pause scanning when a signal level threshold is met
• Pause for N seconds, until clear, or until the enter key is hit
• Record audio

Example usage scenarios..

• Scan entire CSV file with a pause of 2s between channels

• gqrx-scan --type file --pause 2

• Scan lines 1, 2, and 40 through 60 in the file, recording when a signal is detected

• gqrx-scan --type file --channels 1,2,40-60 --record

• Scan FRS, GMRS, and all 145, 146, and 147 frequency channels

• gqrx-scan --type file --pattern "FRS|GMR|14[5|6|7]"

• Scan 28.400 to 28.410 in CW mode, pausing for a signal level of -30 for 10s

• gqrx-scan --type scan --start 28400000 --end 28410000 --mode CW --delaylevel=-30 --delaytime 10

• 28.400e6 is valid too and might be easier to type/read

• Available modes: AM FM WFM WFM_ST LSB USB CW CWL CWU

• Monitor a single channel, recording when the level is better than -50, waiting for 5 seconds before ending recording after signal drops

• gqrx-scan --type file --channels 20 --delaylevel=-50 --delaytime 5 --record --monitor

Command Line Arguments

Scan mode operations

• --start 28400000
• Start at frequency 28.400
• --end 28410000
• Stop at frequency 28.410
• --mode USB
• Scan in USB demodulation
• --step 250
• Step by 250mhz in frequency scanning mode

File mode options

• --channels 19,20,30,40-50
  • Scan channels 19, 20, 30, and channels 40 through 50
• --pattern "FRS|GMR|^145"
  • Scan channels named FRS or GMR or frequencies starting with 145
• --showall
  • Show all channels even if skipped
• --dumpchannels
  • Show all channels, do not tune any

General scan or file options

• --monitor
  • Monitor a single frequency or channel
• --pause 2
  • Wait 2 seconds between frequencies/channels
• --exclude 28.401e6,28.410e6,KY4
  • Exclude frequency 28 401 and 28 410 or channel with KY4 in it

Signal detection options

• --delaylevel=-30
  • Delay scanning if a signal of -30 or better is heard
  • Note that this argument requires the equal sign
• --delaytime 10
  • Delay scanning for 10s when a signal is detected
• --record
  • Record when signal is detected
• --stop
  • Stop scanning until the enter key is hit
• --wait
  • Stop scanning until the channel is clear
• --levelstop=0
  • Do not pause to listen for signal
  • Note the requirement of the equal sign

Defaults vs Command Line

There are options in the script which can be modified to set them as defaults but almost all options (such as signal detection level, scan pause time, etc) can be specified on the command line. To see the script defaults look in the script or the output of the --help command line argument.

Bookmarks file

The CSV file that can be used for scanning pre-set channels is the same format as the gqrx-remote project (https://github.com/marmelo/gqrx-remote) uses, without any headers, with the columns being HZ,MODE,Name

The CSV file path is defined in the file and should be updated for where your file is located.

Example:

28101000,CW,10m CW
28400000,USB,10m Calling
446000000,FM,440 Simplex
144200000,LSB,2m SSB Calling

Pause Script

With this script, you can pause the scanning using a hotkey. How you assign that hotkey is up to your particular desktop environment. The first time ran it creates a file that GQRX Scan uses to pause, the second time it removes it. GQRX Scan removes this file on startup in case it's left over.

Troubleshooting

• problem connecting to "127.0.0.1", port 7356: Connection refused at /usr/local/bin/gqrx-scan line 90
• Enable Remote Control in GQRX. As of version 2.3, this option is always disabled on startup so you have to re-enable it each time you launch GQRX.
• If you changed the IP or Port which GQRX uses for Remote Control, you must update the script to match
• Perl Issues
• Check your dependencies

Dependencies

• GQRX 2.3 or greater with Remote Control enabled

• Perl modules

• Net::Telnet

• Time::HiRes

• Getopt::Long