NC-100, NC-101X


NC-101X with magic eye or S-meter

These receivers are 12 tube super-heterodynes and except for the speaker are self-contained in a table model cabinet which is readily adaptable to relay rack mounting by brackets listed below. The NC-100 is a general coverage receiver covering from 540 Kc to 30 Mc. The NC-101X only covers the ham band. One stage of R.F. and two stages of I.F. are used. Low-loss insulation and high-Q coils give ample sensitivity and selectivity. Separate R.F. and Audio Gain Controls permit complete control of the receiver. A 6E5 tuning indicator tube, with provision for signal strength measurement, provides an added convenience. Other controls are Tone, CW, Oscillator, AVC with amplified and delayed action, a B+ switch, and a phone jack. A self-contained power supply provides all necessary voltages including speaker field excitation.


R.F. 6K7
Mixer 6J7
H.F.O. 6K7
1st I.F. 6K7
2nd I.F. 6K7
Detector 6C5
B.F.O. 6J7
A.V.C. 6J7
Tuning Eye 6E5
push/pull A.F. out (2) 6F6
Rectifier 80

FREQUENCY COVERAGE: The NC-100 covers the range of 540 KC to 30 MC in 5 ranges, 0.54 - 1.3 Mc, 1.3 - 2.8 Mc, 2.7 - 6.4 Mc, 5.9 - 14.4 Mc and 13.5 - 30 Mc. The NC-100 is available with or without a crystal filter. The NC-101X is built and designed strictly for the amateur bands and covers the ranges: 1.7 - 2.0 MC, 3.5 - 4.0 MC, 7.0 - 7.3 MC, 14.0 - 14.4 MC, and 28.0 - 30.0 MC. The Lamb Single Signal Crystal Filter, with separate controls for phasing and selectivity, is standard equipment on the NC-1O1X.

TUNING SYSTEM: The range changing system is unique in that it combines the mechanical convenience of a coil switch with the electrical efficiency of plug-in coils: The coils are, in effect, automatically plugged in. A twist of the Range Selector Knob brings the desired set of coils into position and plugs them in. This mechanism is well supported by the PW Dial and Drive, direct reading to one part in 500. Station logging is consistent and calibration permanent.

CIRCUIT DESCRIPTION: In addition to the R.F. pre-selector, first detector and high-frequency oscillator, the circuit comprises two high-gain I.F. stages using air-core transformers, a triode (cathode-drop biased) second detector, pentode amplified A.V.C. using plate rectification, separate C.W. beat oscillator, and two audio stages, the second of which is of the high-output push-pull pentode type. There is also a cathode-ray tuning indicator (6E5) controlled from the A.V.C. circuit. A heavy-duty power supply is built in the same chassis and there is a separate speaker unit.

BATTERY OPERATION: The battery models, of the above receivers, differ from the A.C. in that 10 tubes are used; the power supply being eliminated and one output tube is used and also that an 8" permanent magnet type of dynamic speaker is used instead of the 10" dynamic speaker supplied with the A.C. model. Power output of A.C. model--10 watts; Battery model--9 watts.


NC-100 -- complete with tubes. AC model- 10" speaker chassis. List Price, $200.00
Battery model -- 8" speaker chassis. List Price, $184.17
NC-100X- complete with tubes and crystal filter. AC model -- 10" speaker chassis. List Price, $237.50
Battery model -- 8" speaker chassis. List Price, $221.67
NC-100S -- complete with tubes. AC model- 12" Rola G-12 Speaker. List Price, $222.50
NC-100XS- complete with tubes ancl crystal filter. AC model- 12" Rola G-12 Speaker. List Price, $260.00
NC-101X -- complete with tubes. AC model .-- 10" speaker chassis. List Price, $215.00
Battery model -- 8" speaker chassis. List Price, $200.00
DCS-10 -- Metal Cabinet for 10" speaker, same finish as receiver. List Price, $8.50
DCS-8 -- Metal Cabinet for 8" speaker, same finish as receiver. List Price, $8.00
RRA Relay Rack Adapters, designed for mounting any of the above receivers in a standard relay rack.List Price, per pair, $2.50

Note: 230 volt 50 cycle and 115 volt 25 cycle models of above receivers available at slightly higher price.

Sources: National Company Catalog from 1937, Communications Receivers the 2nd Edition by Raymond S Moore, A Moving Coil Tuning System for the High-Frequency Receiver by James Millen in the Dec 1936 QST, Dec 1936 Radio World magazine ad.

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