> Other than SWR reduction due to cable loss, the SWR meter should read the > same SWR regardless of where it is on the coax.
Some reasons for changes in indicated VSWR as measured at different points along the line: 1) Line loss. As line loss increases, VSWR will show a better reading closer to the source than at the load, irrespective of the line-to-load mismatch; 2) The bridge/directional coupler's designed line Z does not equal the characteristic Z of the line and the load is a complex Z. (Example: Bird 43 with 50-ohm line section being used on a run of 75-ohm line where the line is terminated into a load with a Z value other than 75 ohms); and 3) Line current imbalance. Normally, current on the outer surface of the inner conductor should equal the current on the inside surface of the outer conductor. Current flow on the outside of the outer conductor will cause line imbalance and incorrect VSWR indications, depending on the magnitude of current on the outer surface of the outer conductor. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
