Context : Compact radio cores associated with relativistic jets are often observed in both active galactic nuclei and X-ray binaries .
Their radiative properties follow some general scaling laws which primarily depend on their masses and accretion rates .
However , it has been suggested that the black hole spin can also strongly influence the power and radio flux of these .

Aims : Here , we attempt to estimate the dependency of the radio luminosity of steady jets launched by accretion disks on black hole mass , accretion rate and spin using numerical simulations .

Methods : We make use of three-dimensional general relativistic magnetohydrodynamical simulations of accretion disks around low-luminosity black holes in which the jet radio emission is produced by the jet sheath .

Results : We find that the radio flux increases roughly by a factor of 6 as the back hole spin increases from a _ { * } \approx 0 to a _ { * } = 0.98 .
This is comparable to the increase in accretion power with spin , meaning that the ratio between radio jet and accretion power is hardly changing .
Although our jet spine power scales as expected for the Blandford-Znajek process , the dependency of jet radio luminosity on the black hole spin is somewhat weaker .
Also weakly rotating black holes can produce visible radio jets .
The overall scaling of the radio emission with black hole mass and accretion rate is consistent with the scale-invariant analytical models used to explain the fundamental plane of black hole activity .
Spin does not introduce a significant scatter in this model .

Conclusions : The jet-sheath model can describe well resolved accreting systems , such as Sgr A* and M87 , as well as the general scaling behavior of low-luminosity black holes .
Hence the model should be applicable to a wide range of radio jets in sub-Eddington black holes .
The black hole spin has an effect on the production of visible radio jet , but it may not be the main driver to produce visible radio jets .
An extension of our findings to powerful quasars remains speculative .