The Hammarlund HQ-145 is a single (below 10 MHz) or dual conversion (10 to 30 MHz) general coverage receiver. It is equipped with both a Lamb crystal filter and an IF T-notch. The HQ-145X sports a single crystal socket for fixed frequency operation. The later HQ-145A replaces the tube rectifiers with solid state diodes, while the HQ-145AX had 11 switched crystal sockets in addition to the variable HFO. The intermediate frequencies are 455 KHz and 3035 KHz.
"HQ-145X Communications Receiver, Technical Description and Operating Instructions", Hammarlund Manufacturing Company (A Giannini Scientific Company), April 1962.
"Communications Receivers, The Vacuum Tube Era 1932-1981", 3rd Edition, by Raymond S. Moore
"Shortwave Receivers Past & Present", 2nd Edition, by Fred Osterman
HQ-145X in my boatanchor shack