1939 -- The high performance communications receiver for the VHF
enthuseast and experimenter -- the 27-62 Mc. National NHU.
World War II -- Thousands of National receivers were manufactured for the
war effort in dozens of configurations. In fact, National manufactured more
than 70 different receivers for the government during World War II -- one
of the best known was the 190Kc-30Mc RAS. [The RAS did not have the
S-meter, crystal filter or band spread features of the HRO. It's IF was
also shifted to 175Kc. This allowed it to provide complete coverage of the
maritine frequencies between 190Kc and 550Kc.]
Row upon row of National receivers were used in military installations
-- nine of of ten Navy ships relied upon National receivers for
communications.
A famous war-time compliment to National -- the receiver on the right is an
identical copy of the HRO manufactured by the Germans for their military
communications.