An improved adaptive high power vector network analyser for HF antenna tests

Meaningful impedance measurements of short HF antennas can be performed with a set-up consisting of an automatically sensing high power generator, combined integral reflection meter, tuneable preselection filter and a remote field probe. These are combined as a customised vector network analyser. The idea is to avoid measuring equipment destruction by using an automatic adjustment of test port power. Severe external interference that is typical of HF transmitter sites necessitates the use of band-reject or band pass filters before the detection of reflected voltages. Proper HF antenna tuning should be based on simultaneous information about true radiation efficiency. A small UHF link provides the telemetry path from the suggested HF field probe to the network analyser's through port.