The Story of an Old Timer: Radio Landing Aid

Here's a picture in May 1927 as they prepared to experiment with this new radio landing aid. That is Dellinger on the left and Dunmore to his side.

Below is the basic cockpit instrumentation they developed with the three conditions of travel along the beacon course. Pilots will recognize the beginning of instrument blind navigation.

Also during this time period, the Radio Section did ionospheric soundings - to show the relationship of solar activity and its effect on radio transmission - both diurnal and seasonal.

And the fact that there were multiple levels of the ionosphere and magnetically their effect on radio transmission and propagation at different frequencies.