Note
QST, Jul 1955, p. 132, and others.
QST, Aug 1955, p. 82. Photo and Specs
QST, Sep 1955, p. 101. (specs)
QST, Nov 1955, p. 79. (specs)
QST, Mar 1956, 102. (price information)
CQ, Mar 1962, p. 128. (close out)
QST, Mar 1962, p. 160. (close out)
The GPR-90 receiver from the Technical Materiel Corporation also carried the R-825/URR military designator. The 15-tube, double-conversion set was single-conversion below 3.2 MHz. It covered .54–31 MHz. It used a crystal filter and offered selectivity from 200 Hz to 5 kHz in six steps.
