Spectral index determination between 408 MHz and 5 GHz in the northern sky

We present the joint analysis of two 5-GHz interferometric surveys of the n orthern sky, taken with different baselines. The two surveys were carried o ut on the Jodrell Bank 5-GHz interferometer based at Manchester. The Maximu m Entropy Method is used to check the consistency of the two surveys and th e final two-dimensional maps are used, together with low-frequency full sky surveys, to put constraints on the Galactic spectral index. It is found th at synchrotron emission is the dominant process at high Galactic latitudes below 5 GHz.