Hallicrafters S-53A

Contact: 

The S-53A is a cheap (about 80 $) communications receiver produced by Hallicrafters from 1951 to 1959. It superseded the S-53 introduced in 1948 and was replaced by the S-107. The receiver is clearly a transition-era design, mixing miniature and octal tubes. The unit covers the spectrum from the AM Broadcast band up to 31 MHz. In addition the 6-meter Ham band (50-54 MHz) is also included. When tuned to this band the receiver pulls in a lot of spurious FM broadcasts, clearly due to the 2nd harmonic of the local oscillator. In addition the low value of the IF (455 kHz) makes image rejection close to nil (each station is received in two places of the dial) so the 6-meter band is essentially useless today.

Probably to reduce the image problems, the predecessor S-53 had a 2075 kHz IF. However this resulted in insufficient selectivity, so in the S-53A Hallicrafters reverted to a more conventional 455 kHz IF strip.

The S-53A has no RF stage and the BFO cannot be tuned, making reception of SSB signals quite challenging. There is no S-Meter, but Hallicrafters supplied the diagrams for connecting an external S-Meter. On the other hand, there is a built-in speaker which delivers a very pleasant audio.

I got my S-53A through Ebay USA. To get the cheapest shipping rate to Europe the delivery took four months! After inserting two missing tubes the unit started operating well, and I used it occasionally to listen to a local AM station. In 2016 I decided that it was time to recap the unit, since almost all the cylindrical paper capacitors were leaky. In this process I discovered that my radio was not exactly wired according to the schematic in the manual in the Automatic Noise Limiter section. Moreover the plate voltage on the RF/IF section was too low. A quick search on the Internet showed that my radio followed the S-107 schematic, with the RF/IF plate supply derived from the last filter capacitor (193 V instead of 225 V.) So mine was one of the latest produced units. I am now planning to check the alignment. The S-53AU (Universal) model can be operated on 220 V, but I had to install a step-down transformer from 220 to 117 V. I used an inexpensive transformer for industrial controls I had in my junk box. See here for the schematics.

S-53A Owner's manual (BAMA)

		Hallicrafters' advertisement in the 1951 Radio Amateur's Handbook showing the S-40B/S-77, S-53A and S-38B. The S-53A was said to be better than the S-38B but inferior to the S-40B.
		The tuning dial with the A,B,C,D,E bands plus the logging scale simply numbered from 0 to 100. The 6-meter band (50-54 MHz) is tuned using the banspread control (lower pointer.)
		The rear side. There are simple screw-type terminals for a balanced antenna plus a grounding jumper to be used with a coaxial line. The earphones are connected via banana plugs and the internal speaker can be disconnected via a slide switch. A phone plug is also present.
		Top view of the inside
		Tube placement
		Detail of the chassis and of the 2-gang tuning capacitor
		The built-in 5" PM speaker is attached on the top cover which opens on a piano hinge
		The manufacturer's label on the back of the chassis.
		To remove the two large tuning knobs use an Allen wrench (metric size is also OK.) A Phillips (cross) screwdriver must be used for the three small knobs.