We study the angular dependence of the flux from partially synchrotron self-absorbed conical jets ( proposed by Blandford & Königl ) .
We consider the jet viewed from either a side or close to on axis , and in the latter case , either from the jet top or bottom .
We derive analytical formulae for the flux in each of these cases , and find the exact solution for an arbitrary angle numerically .
We find that the maximum of the emission occurs when the jet is viewed from top on-axis , which is contrast to a previous result , which found the maximum at some intermediate angle and null emission on-axis .
We then calculate the ratio of the jet-to-counterjet emission for this model , which depends on the viewing angle and the index of power-law electrons .

We apply our results to the black-hole binary Cyg X-1 .
Given the jet-to-counterjet flux ratio of \gtrsim 50 found observationally and the current estimates of the inclination , we find the jet velocity to be \gtrsim 0.8 c .
We also point out that when the projection effect is taken into account , the radio observations imply the jet half-opening angle of \lesssim 1 \degr , a half of the value given before .
When combined with the existing estimates of \Gamma _ { j } , the jet half-opening angle is low , \ll 1 / \Gamma _ { j } , and much lower than values observed in blazars , unless \Gamma _ { j } is much higher than currently estimated .