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The monoclipper - so called because it employs the circuitry of both the Monitone and the Clipper (see ARRL Handbook) - is a unit that was built here at W6ICB. Fig. 1 will be recognized as a combination of the circuits appearing as Figs. 5-38 and 8-12 of the '54 Handbook, plus a Type 6AQ5 audio amplifier. The audio amplifier was added to assure adequate output for speaker operation.
Fig. 1. (A) is the circuit diagram of the Monoclipper;
(B) shows a suggested method of connecting the unit to the receiver, speaker, and phones.
An old a.c. radio chassis was used as the base for the Monoclipper. The power supply and the audio-amplifier circuits of the broadcast set were left intact and then reused as part of the new set-up. The monitor and the clipper circuits were mounted on the b.c. chassis in the space originally occupied by the r.f. components for the receiver. The actual placement of the new parts and the wiring of same are not especially critical so long as the r.f. input section to the monitor is kept away from the rest of the circuit.
The oscillator section of the Monoclipper is different than that of the Monitone in that the full output of the neon oscillator is used. With a tapped-down output circuit as originally used, the output was too low for speaker operation.
The finished product is equipped with a masonite panel and is wired to the receiver, the speaker and the 'phones as shown in the lower section of Fig. 3. In this part of the circuit, S1 selects the source of output - either the receiver or the Monoclipper - and S2 in turn feeds the output to either the 'phones or the speaker.
When operating the Monoclipper it is advisable to adjust the output of the neon oscillator by means of R1 and to employ R2 as the audio gain control. The receiver audio gain control should be adjusted for the desired clipping level. After the initial adjustment of the entire circuit, it is usually possible to leave the receiver control and R1 alone and use only R2 as an adjustment.
Don Lafferty, W6ICB.