Note
73, Dec 1961, p. 66.
Manufactured by the R. E. Goodheart Company, the QX-535 is a 200 to 550 kHz receiver. The unit is essentially a military-surplus BC-453 command set receiver repackaged into a self-contained, perforated metal cabinet.
Unlike the original stock BC-453, the QX-535 includes an integrated, fused transformer-type power supply, a front-panel speaker, and complete local controls.
The cover of the BC-453 is removed inside the ventilated enclosure to ensure adequate heat dissipation.
The 85 kHz IF transformers feature adjustable slug coupling (accessed by removing the screw-on caps on the IF cans). Pulling the small shafts out sets the coupling to minimum for maximum selectivity.
Specifications
– Frequency Range: 200 to 550 kHz with 10 kHz dial divisions.
– Circuitry: 6-tube superheterodyne with a full-wave tube rectifier.
– IF: 85 kHz utilizing three double-tuned circuits.
– Selectivity: 2.0 kHz bandwidth at 6 dB down; 6.5 kHz bandwidth at 60 dB down.
By coupling the QX-535 to the output of a primary receiver's 455 kHz (or 200–550 kHz) IF strip, it converts the signal down to its own 85 kHz IF. This dramatic reduction in bandwidth allows operators to reject adjacent-channel interference on crowded phone or CW bands.
Combined with single-band or switched crystal-controlled converters, the QX-535 serves as the heart of a stable, sensitive, and highly selective complete ham-band receiver setup.
