Antennas in the frequency range 10 to 300 MHz are being designed with all-sky coverage, a low response at the horizon to minimize interference from terrestrial sources, negligible ground loss and a good low noise match to the low noise amplifier (LNA). Other features include low cost, dual polarization and good performance over more than an octave bandwidth. Extending the antenna performance over a wider frequency range and accurate calibration are remaining challenges. Modeling of the antenna and its associated low noise amplifier shows promise as a method of improving calibration accuracy.