How to do DVB-S2/S blindscan on Linux

By | September 2, 2011

There is already blindscan capability in TBS Linux driver,but to make full use it, you need to write a ‘shell-script’ which consists of several simpler steps.In Windows primary reason that special tool for blind-scan is needed is because there is no standard way to get-back from the driver the details about the locked frequency during the blind-scan, but in Linux that’s part of the Linux DVB API and the function with which you can get back the signal parameters and details from the driver is called ‘get_frontend’ and you can call with it many tools (i.e. without need to program in any language) – for example:

# dvbsnoop -adapter 1 -s feinfo

in fact TBS Linux drivers are the only DVB-S2 drivers that implement full support for ‘get_frontend’ Linux DVB API function. So, if you haveLinux driver that doesn’t implement ‘get_frontend’ Linux DVB API function (i.e. you use no TBS hardware) then like in Windows you will need special tool for blind-scan even if the hardware can do blind-scan, otherwise (when implementation of ‘get_frontend’ Linux DVB API function is in place like in case of TBS drivers) you can use ‘shell-script’, because blind-scan consists of few simple steps every one of each can be done with single command line:

0) for any frequency in the range X,Y with step of Z MHz:
1) send tune request to frequency T (for example that can be done with ‘szap-s2’ tool)
2) check the lock status with calling ‘get_frontend’ Linux DVB API function and in case of lock that will give you all signal parameters
(for example it can be done with ‘dvbsnoop’ command line i gave above), i.e. effectively result in what blind-scan is supposed to do for you – then you report with all details for all frequencies on the satellite that exist and can be locked

and since those steps above require only command lines involving ready tools : ‘szap-s2’ and ‘dvbsnoop’ they can be automated in ‘shell-script’. so, more experienced Linux users already wrote such ‘shell-scripts’ for themselves and use blind-scan that way.

Since not so experienced linux users will have difficulty in writing this “shell-script” by themselves, TBS will prepare such ‘shell-script’ and include it in the next driver release for easy use of every Linux user.

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