As described in the SCR-269 section, a radio compass is a radio receiver connected to a directional antenna. It allows the navigator to determine the direction of a distant transmitter. A second bearing to another transmitter allows the aircraft’s position to be determined.

The MN-26 system in the exhibit includes the MN-26 receiver, the MN-28 control box, the MN-20 loop antenna, and the MN-40 azimuth indicator. Only the MN-28 is a documented Argus product (based on references in Argus Eyes that can be found on two hanging boards in the exhibit). It is possible that some components of the MN-26, such as its power band switch or some of the soldered component strips in its base, were also made by Argus.


The MN-26 in this exhibit was sold to us by Jay Wisler of Warbird Parts and Memorabilia in Tampa Bay, who gave us nice discount on shipping. It was packed in its original box in March of 1945. The box was then coated with wax and put into storage, so the receiver found its way to us untouched for 70 years. It came with a beautifully illustrated manual that allowed us to properly connect the MN-28 control box and get the internal dynamotor power supply to work. We turned the receiver on and it functioned perfectly, a testament to the quality of its construction so many years ago. After a few minutes the old paper capacitors in its base began to short, but since replacing them it has worked fine.