1967 Heathkit Model GR-54 "Deluxe SWL Receiver"

This is a Heathkit Model GR-54 radio. This is the first of many Heathkits that I have built. The radio has 6 tubes and 5 bands covering:
Band A: 180 to 420 kc
Band B: 550 to 1550 kc
Band C: 2 to 5 Mc
Band D: 5 to 12.5 Mc
Band E: 12.5 to 30 Mc
The radio has a bandspread and a BFO to receive CW and SSB. An RF gain control and Automatic Noise Limiter is also included. It also has a relative signal strength meter, but I added an external Lafayette Model 99-2512 "S"-meter unit that can be seen on the top of the radio. The IF for this radio is an unusual 1682 kc with the IF bandwidth set by a crystal lattice filter that provides excellent selectivity. The radio has a antenna tuning control to improve antenna matching. There is also a standby switch. I was an avid shortwave listener back then and I have several QSL cards from several foreign stations. See the QSL card page to see these cards.

I have seen discussions regarding hum in the audio of this radio. My radio was no exception and this radio had hum right after I built it, the loudness of which would vary with the audio gain control when the radio was placed in standby with the standby switch. I eventually solved the hum problem. Heathkit assumed the ground connection from the main circuit board to the ground of the volume control is adequately made through the chassis. It turns out this assumption is not valid. To minimize the hum, I soldered a wire from the ground plane of the main board to the ground lug of the volume control potentiometer. At first glance, this may appear redundant but this solved the problem and the radio is quiet as far as hum is concerned.

I used this same approach to minimize hum in one of my Heathkit SB-610 monitor scopes. That scope had a slight hum it its trace, and I minimized the hum by running a wire from the chassis ground on a tube, to the ground lug of the vertical gain potentiometer. Thus using the chassis as a ground between a gain control and its amplifier is not good design practice.

Tube Compliment
BFO & Prod Det
Audio Output
Tuning Eye
Rider's Manual Page #
2 x 6BA6

Below are details on this receiver as advertised in the 1966 Heathkit Catalog.

Page 90 of 1966 Heathkit Catalog Showing the GR-54 Shortwave Receiver

Below is the cover of the 1966 Heathkit catalog. Note that the GR-54 shortwave receiver is featured on the upper right corner of the cover.

1966 Heathkit Catalog Cover