[R-390] R390A Turns Counter BFO option?

[Nick England]

FWIW -From "Cryptologic Collection Equipments" NAVEDTRA 10251 (1977)
http://www.navy-radio.com/manuals/crypto-equip.htm

BFO PITCH.-The BFO PITCH control
varies the output frequency of the BFO above
and below 455kHz. The normal R-390A BFO is
designed to vary by 3kHz above and below
455kHz. Many of the R-390A receivers with
which you will come into contact have a
modified BFO pitch control, called a
MICRODIAL. This modification enables the
BFO to be varied over a 26kHz range (13kHz
above and below 455kHz.)

cheers,
Nick K4NYW
www.navy-radio.com