Abstract
Some preliminary results-are: 1) the most frequently used control is that for tuning. Some form of discrete turning (pre-selection) for 5 or 6 transmitters may be sufficient for normal use. 2) a separate on-off control is desirable. 3) for in most radio-car combinations the turning scale is insufficiently visible for the driver from his seat. Preferably, he should not have to look at all at the radio while using its controls.