Coupling experiments, using a gas feed near the Lower Hybrid Current Drive (LHCD) launcher, have been carried out in JET. An improvement in coupling for a given plasma - launcher distance can be obtained when the gas flow is large enough (> 2.5x1021el./s). During these experiments, modification of the wall recycling was observed and the relation with the observed improvement in coupling is presented. For high gas flow (> 5x1021el./s), a significant reduction in the suprathermal electron population, as determined by non-thermal electron cyclotron emission and hard X-ray emission, is observed. Visible light imaging of a sector of the divertor indicates that some power might be coupled to the Scrape-Off Layer when the injected gas flux is too high. At low gas flow, the coupling can be improved without affecting the LH power absorption in the plasma core.