Note
QST, Mar 1939, pp. 1–10.
Lafayette catalog number 78, p. 148.
The SX-23 "Skyrider 23" was introduced in the March 1939 issue of QST with a full ten page spread, complete with an introduction by Bill Halligan himself. Promoted as "driftless" receiver.
The "deco" design is unique among Hallicrafters products. Chassis and transformer covers are all painted dark gray and stamped with the Hallicrafters logo.
The Hallicrafters SX-23 "Skyrider 23" was a significant engineering departure from the company's established line of black-panel, silver-dial sets. Aimed at competing head-on with premium receiver manufacturers like National and Hammarlund, it was a high-end communications receiver priced at $115.50 (a steep contrast to the $69.50 budget-friendly SX-24 that followed shortly after).
Because it was only produced for a short period and suffered from poor sales, it is considered a rare find for modern collectors.
The receiver features a heavy steel chassis with reinforcing end bends for structural rigidity, painted in a dark, glossy gray. The cabinet layout integrates distinctive modern "vent grilles" designed to visually coordinate with its matching external speaker.
Unlike previous Hallicrafters designs that relied on off-the-shelf standard components to undercut market prices, the SX-23 utilized IF coils, transformers, and a filter choke housed in custom cases embossed with the classic Hallicrafters "h" logo.
The most prominent feature of its physical design is the stylized "Venetian blind" center dial. While touted as an ultra-modern aesthetic upgrade that integrated both the S-meter and the band indicator, it was criticized in practice for making the meter and indicators difficult to read.
Frequency coverage from the AM broadcast band up through 34 MHz.
The SX-23 relies on a large, three-gang 437-pF variable tuning capacitor. While this arrangement worked fine for lower frequencies, it caused incredibly "fast," touchy, and bothersome tuning on the upper shortwave bands (5.2–16 MHz and 10–34 MHz).
To spread out the 80-, 40-, 20-, and 10-meter amateur bands, the bandswitch routes the broadcast-style main capacitor through a highly complex matrix of switched, high-tolerance fixed series and parallel capacitors. This design required a completely dedicated page in the service manual just to map out the capacitance networks.
Rather than a direct frequency readout for the amateur bands, the bandspread dial features a generic 0–100 linear scale. Because of this, every individual unit shipped from the factory with a unique, custom-calibrated bandspread chart matched specifically to the receiver's serial number. There is no bandspread function provided for commercial or non-amateur frequencies.
Despite its tuning flaws, the rigid chassis design paired with temperature-compensating capacitors gives the SX-23 excellent frequency stability compared to prior models. It retains great sensitivity and utilizes a highly regarded crystal filter circuit that Hallicrafters later copied into the SX-24 and SX-25 lines.
Tube lineup:
– RF Stage: 6SK7
– Mixer & Oscillator: 6SA7 mixer with a separate 6SJ7 high-frequency oscillator (a major performance advantage)
– IF Stages: (2) 6SK7s operating at 455 kHz
– Detector & Audio: 6SQ7 detector-audio stage driving a 6F6 power output tube
– Auxiliary Circuits: 6SJ7 Beat Frequency Oscillator, a 6H6 Dickert-style noise limiter, and a 6B8 AVC amplifier-rectifier
– Power: An 80 rectifier tube
Coverage: 540 kHz to 34 MHz
IF: 455 kHz
Calibrated bandspreads for 80, 40, 20, and 10 meters
S-meter
BFO
ANL
Crystal filter
Variable selectivity
Power: 120 VAC, 110 watts
