[Jeffhs]

The National Company also made communications receivers for the U. S. military during World War II. These were solidly built receivers that weighed a ton! My dad had one (the Army's designation for it was RAO-7) in his workshop in our basement for years, but I think the power transformer may have given up the ghost (or else the rectifier tube[s] went West) as by the time I moved out of our house in 1999 the set hadn't been working for some time. The RAO-7 was an all-band receiver, covering 550 KHz (kilocycles in the war years until 1967) to 30 MHz in five bands. I listened to Morse code practice from the American Radio Relay League's headquarters amateur radio station W1AW, as well as other amateur and SW stations, on this set as part of my early training for an amateur license. The receiver had just about every high-end feature one could imagine, such as a Q-multiplier (what hams used to call a Q5-er years ago), a real analog S-meter (not a flimsy, useless LCD bargraph display such as is common on today's receivers and even amateur transceivers), variable RF gain, a bandswitch you couldn't wear out if you tried (the coils were on a turret turned by the huge bandswitch knob on the front panel), et al.

The RAO-7's performance, moreover, would put many of today's inexpensive SW sets to shame. Hook up a decent antenna to this monster and you could hear just about any station from Maine to Miami on the broadcast band, not to mention U.S. and foreign broadcast stations on SW. This receiver was, IMO, one of the best sets National ever made; I'm sure many beginning postwar DXers would have given their right arm for a set like this, as they were built for long-distance reception (again, with a good antenna connected).

I always liked National's stylized "NC" logo, which was inside a diamond shape on the front panels of all WWII and later vintage National communications receivers (and the company's television sets from the early 1950s until the firm finally went out of business, probably either in the late '50s or very early '60s). The C in the logo was formed by adding two short horizontal lines to the top and bottom of the right side of the N. I wonder if National got the idea for this logo from NBC-TV's old "snake" identification, which it used (along with the NBC chimes) after every NBC television program from the mid-fifties through the mid-seventies?
The B in that logo was formed by two loops added to the right side of the N, and the C snaked across the bottom of what became NBC's signature to finish it off.