In accordance with National's policy of constant improvements, the mechanical details of the NC-100X have been redesigned to give new ease of control, while keeping the chassis unchanged. Particularly notable is the new dial with direct reading scales for each band, calibrated in Megacycles. The pointer is ganged to the band-change mechanism and moves radially to point directly to the proper scale. An additional high-speed dial reads to one part in a thousand, for accuracy in logging. Other changes include the use of a meter for signal strength measurement instead of a "magic eye" and complete restyling of the cabinet. Although the time-proven chassis remains unchanged, the cabinet has been made slightly larger to accommodate the dial. The new models will be designated the NC-100XA and the NC-100A. The primary difference being the NC-100XA has a crystal filter and the NC-100A does not. Older models can be factory-rebuilt to include the new features at a net cost of $25.00, by arrangement through your dealer.


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
push/pull A.F. out (2) 6F6
Rectifier 80

FREQUENCY COVERAGE: The NC-100XA 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.

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.

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. 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-100XA complete with tubes and crystal filter, AC model, 10" speaker List Price, $237.50
NC-100A complete with tubes, AC model, 10" speaker List Price, $200.00
NC-100XSA complete with tubes and crystla filter. AC model, 12" Rola G-12 Speaker List Price, $260.00
NC-100SA complete with tubes. AC model, 12" Rola G-12 Speaker List Price, $222.50

Source: National Radio Products Catalog #280L, June 1938 QST

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