A handheld emitter-receiver device suitable for the direct estimation of the velocity of radio waves in air is presented. The velocity of radio waves is measured using the direct time-of-flight method, without the need for any tedious and precise settings. The results for two measurement series are reported. Both sets of results give an estimate of the velocity of radio waves in air that is within an error of 16% of the accepted value. The method can be used with success during a field-trip or picnic and it is appropriate for both high-school and university-level student projects. (Contains 6 figures.)