Navigational Ruler Radio Direction Finder

This is an unusual and rare type of radio direction finder. It is actually a "ruler-radio". The intent is very clever... it was meant to eliminate a step in plotting a course by radio beacon. Normally one would have a compass built in, and the navigator would take a bearing to the antenna, then plot the bearing on a chart. In this instrument, there is no compass... the ruler would be on the chart to begin with, the direction to the antenna found by rotating the ruler and listening for the null in the signal, and the bearing then could be plotted directly on the chart. A great idea in theory, but in practice all boats slew to some extent... even at anchor... and as your boat moved, so moved your chart's orientation, and then, so would your plot line.

For more information about RDF's, and to see all the radios in my collection:
http://www.angelfire.com/space/proto57/rdf.html

Category:

Science & Technology

Tags:

• navigation
• radio
• direction
• finder
• marine
• electronics
• vintage