In order to phase match the cables,
you would need to know the characteristics of the
two cables. If you know the dielectric being used
in each cable, then you can compute the 'guide'
wavelength in each cable, given by, lambda_g = 300/(f*sqrt(e_r)
), where, f is in MHz and lambda_g is in meters
and e_r is the relative dielectric constant of the
cable. Based on this, you can compute the total
phase for a given length of cable (at that frequency)
since 1 lambda_g = 360 degrees. Based on this, you
can phase match the two cables.
I hope I
have understood your question right and that this