Note
QST, Sep 1951, p. 92. (2BR and 3BR)
QST, May 1952, p. 132. (1BR)
QST, Apr, 1952, p. 103.
QST, Jun, 1952, p. 119.
Allied Radio catalog 1953 (copyright 1952)
QST, Feb 1954, p. 87. (inside view)
QST, Apr 1954, p. 95. (5BRF) (a month or two earier than this, this unit is designed specifically for use with the FTR)
QST, Apr 1954, p. 95. (5BRLN) (designed for use with broadcast receiver)
QST, Apr 1954, p. 95. (5BR-1) (same as LN except with noise limiter)
An "LN" version (2BRLN, for example) does not include the noise limiter.
See QST, Jun 1952, p. 111.
5BR
QST, Mar 1953, p. 94.
5BR-1
QST, Dec 1953, p. 107.
By June, 1954, the 5BR series was the only one still available.
QST, Apr 1957, p. 127. (5BR-2)
QST, Apr 1959, p. 108. (maybe NOS)