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Accessing Expert raw command mode

Example - Investigate running processes, CPU, Memory utilization etc.

There are situations when predefined commands in Administration windows are not enough. Fortunately it is possible to execute any Linux command from Administration window by selecting Functions=>Administration, then double click at label "Command" the text box shows up and Expert mode is enabled. You're on your own now. Any command typed in the command text box has priority over the selected from drop-down list, only if the command text box is empty the command from the drop-down list is executed instead. On the picture bellow command top -n 1 is executed but in the newer version of MNM4SDR you can simple select "Running processes" from drop-down list to get same effect.

Example - Calibrate DVB-T dongle

Accessing to raw command mode is described in previous example. You must had installed kalibrate-rtl package https://github.com/steve-m/kalibrate-rtl. As the DVB-T dongles we are working with are not built for accuracy and frequency error exists it is important to find out its value.
1. Type command kal -s GSM900 for instance to find out available GSM base station in GSM900 band in your surrounding. Executing of this command takes a while, a couple of minutes on my system, so be patient. The command output shows my USB dongle frequency offset is from -17.353kHz to +15.631kHz


2. Now you can adjust offset of your dongle to some of GSM channels in vicinity. I'll choose the one with highest power and it is channel 65. Execution of command kal -c 65 is going to give the average absolute error and it is 17.846 ppm.


3. The value of ppm could be used now, for instance in Analyzer functionality. We can set the correct ppm value and override a ppm value retrieved from eeprom.

Last edited Jul 29, 2015 at 10:24 AM by skrilic, version 12