AR-3 Communications Receiver

Features

• Covers 550 KC to 30 MC in four bands.
• Slide-rule dial—electrical band-spread—ham bands marked.
• Slug-tuned coils and efficient IF transformers for good sensitivity and selectivity.
• Transformer operated power supply for safety and high efficiency.

This Heathkit model AR-3 Receiver features proven circuit design and physical layout. The net result is good sensitivity and selectivity, coupled with more flexible overall operation. Performance of the AR-3 is really outstanding, especially in view of its low kit price.

High Q slug-tuned coils are used in the front end and an antenna trimmer has been added so that the front end may be peaked to a particular signal on any of the bands. The coil layout permits easy alignment from above the chassis. Predesigned oscillator coils result in increased conversion transconductance through the mixer circuit, and new-type IF transformers allow a better band pass curve, and more gain. The tuning capacitor is shock mounted, and the overall layout eliminates ground loops, shortens important lead lengths, and makes for easy assembly.

The physical layout of the AR-3 is designed for high circuit efficiency, and for convenience in construction. Frequency coverage is from 550 kc to 30 mc in four bands clearly marked on a slide-rule dial. The ham bands are also plainly marked. The circuit employs a 12BE6 oscillator and mixer, a 12BA6 IF amplifier, a 12AV6 second detector, AVC, first audio amplifier, and reflex BFO, a 12A6 beam power output tube, and a 5Y3 rectifier. THe power supply is transformer operated for safety and high efficiency. A band switch eliminates coil changing, and provision is made for main tuning—bandspread tuning—phone-standby-CW switch—headphone jack—antenna trimmer—noise eliminator—RF gain control and AF control. Two dial lights are provided to illuminate the tuning dial softly. Accessory sockets are provided on the rear of the chassis for using the Heathkit-model QF-1 Q Multiplier. The accessory socket is handy also, for operating other devices that require plate and filament potentials. It will supply +205 volts DC at 15 ma and 12.6 volts AC at 300 ma. Slug-tuned coils allow close tracking adjustments. The BFO (beat-frequency oscillator) circuit is more stable and delivers greater audio output when receiving CW signals. The standby switch prevents voltage surges and resulting audio blasting during switching. Ceramic bypass capacitors have been used freely to reduce stray coupling in signal circuits. In all, the model AR-3 offers tremendous improvements over the previous model and is a fine receiver for the beginning amateur, short wave listener, or for anyone whose listening interest extends beyond the standard broadcast band. No special antenna is required. Any long wire end-fed antenna can be used for maximum signal pickup. A signal generator is recommended for final alignment for best results. Shpg. Wt. 12 lbs.

CABINET:
The 91-15A cabinet for the AR-3 is both attractive and practical. It provides protection of all components of the completed receiver as well as improving its appearance. The tone quality of the speaker is also improved by the cabinet. THis pyroxylin impregnated fabric covered cabinet includes the aluminum front panel, reinforced speaker grille, and protective rubber feet. Front panel is screened, indicating function of the various controls. Measures 12¼" W. x 6¾" H. x 7¾" D. No. 91-15A. Shpg. Wt. 5 lbs.

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