A receiver designed to measure the galactic noise spectrum in the range from 2 to 4.5 MHz and flown in the Ariel III satellite is described. Problems arising from the use of a loop antenna with a swept receiver and the exclusion of spurious signals from terrestrial sources and other experiments in the payload are discussed. Preliminary results indicate a marked coupling between the receiver and another experiment in the satellite by modulation of the local plasma. In certain conditions the coupling is small enough to be neglected and the galactic noise level can be measured with fair accuracy.