The 13 sympathetic strings add this special feel to the sitar and what it makes this Electric sitar so unique.
The gauges of the sympathetic strings are all 0.10 strings and a harp wrench is used for the tuning process.
The longest and lowest string is tuned an octave above the high E of a standard tuned guitar.
From there, the strings are tuned in half steps.
This is just a starting point and experimentation since you are free to tune it in any other configuration.
You can tune the instrument with a "drop D" tuning and the sympathetic strings to a D7sus chord, which is as follows - longest string to shortest string.
D, F#, G, A, C, A, G, F#, G, A, C, D, D - same as previous note
And the 6 string tuning is just like any other guitar.
I have set this guitar with a 0.10 set of strings, which is Blue steal Dean Markley String Gauges: .010 .013 .017 .026 .036 .046 tuned with out the dropped D on the low E string.
So it’s just tuned like a normal guitar tuning.