Computer models of Kabul, Afghanistan, medium-wave antennas

Design and implementation of new feed systems for two Russian-built skirted Franklin vertical antennas near Kabul, Afghanistan, were accomplished using moment method techniques. To facilitate re-tuning to new operating frequencies, the original stub-tuned matching network was replaced with a conventional "T" network. The proper settings of the terminating stubs on the lower skirts in order to obtain the desired current distributions were also evaluated by moment method techniques. At the completion of the installation, the measured drive impedances correlated very well with the calculated values, indicating achievement of the desired performance.