Tuning an Electrically Short Antenna for Field Operation

One of Prof. Tapan Sarkar’s pet projects was positioning of antennas for portable operation, and we had many exchanges on this topic and sunspots and their effect on HF propagation. Now Sun Cycle 25 is building and increasingly favoring radio operation in the HF band (1.5 to 30 MHz). There are military and other radio applications for 5 to 20 W battery-operated radios with whip antennas that make the radio portable. A whip antenna has no ground return or proper counterpoise, so is not optimized for signal propagation. Thus, some users drag a wire behind. This solution is not ideal. We explore optimizing antenna performance for HF, VHF, and UHF (spanning 1.5 to 512 MHz) manpacks and using an antenna tuning unit (ATU). Battery-operated manpacks with internal ATUs were used for testing, comparing internal ATUs with the performance obtained using external tuners. The necessary mathematical treatment for this case is provided. Prof. Sarkar was involved with the modeling software WIPL-D and HOBBIES. Some anecdotes will be provided with interactions with him on these.