National Radio NC-140 Instruction Manual

Here are the features of the NC-140 which are normally
associated with much higher priced equipment:
OC Double Conversion above 4 mc for rejection of annoy-
ing spurious signals and images.
O Vacuum Tube Q-Multiplier operates on AM and
CW/SSB for continuously variable IF selectivity to
reduce adjacent channel interference and heterodyne
whistles.
O 6BZ6 RF Stage for top signal sensitivity and front-end
selectivity.
O National's Exclusive Dial Selector for accurately cali-
brated foreign broadcast bandspread as well as amateur
bandspread. If you listen to foreign broadcast, you can't
afford to be without this feature!
O Five main tuning bands instead of the usual three or
four provide superior calibration and stability on fre-
quencies above 10 mc.
SPECIFICATIONS
MAIN TUNING RANGES: 540-1600 KC, 1.6-4.0 MC, 4.0-10.0
MC, 10.0-20.0 MC, 20.0-30.0 MC. INTERNATIONAL
BROADCAST BANDSPREAD: 13 meters: 21.5-22.1 MC,
16 meters: 16.4-18.0 MC, 19 meters: 14.6-15.4 MC, 25 meters:
11.7-12.0 MC, 31 meters: 8.6-10.0 MC, 49 meters: 5.9-6.3MC. 0
AMATEUR BANDSPREAD: 10 meters & CB: 26.6-30 MC,
15 meters: 21.0-21.5 MC, 20 meters: 13.8-14.5 MC, 40 meters:
6.9-7.5 MC, 80 meters: 3.5-4.0 MC. 0 CALIBRATION: Bana-
spread dials calibrated every 20 KC or better below 10 meters;
10 meter amateur and CB calibrated every 50 KC. O DIAL
SELECTOR: allows foreign broadcast calibration equal to
amateur band calibration. CONVERSIONS AND INTER-
MEDIATE FREQUENCIES: double conversion above 4 MC;
1st IF 2215 KC; 2nd IF 230 KC. O SENSITIVITY: Better than
1.0 microvolt for 10 db S/N ratio. SELECTIVITY: Q-multiplier
for AM and CW/SSB provides continuously variable selectivity
from less than 500 cycles to 8 KC. G RECEPTION OF CW/
SSB SIGNALS: Calibrated USB/LSB BFO control, Q-Multi-
plier, stable 230 KC BFO. 0 SIGNAL STRENGTH METER:
Edge-reading; calibrated in S-units from S-1 to S-9 and 10 db
to 60 dk above S-9. 0 AUDIO POWER OUTPUT: 3.0 watts;
3.2 ohms for loudspeaker, separate front panel headphone
jack. ANTENNA INPUT: 50 ohms; unbalanced.
CONTROL CIRCUITS: Front panel standby-receive switch
for control of transmitter; external control of receiver if
desired. FRONT PANEL CONTROLS: Main tuning,
bandspread tuning, audio gain, RF gain, antenna trim,
rec-standby, ANL On-Off, AGC On-Off, BFO On-Off, Dial
Selector, BFO-USB/LSB, selectivity, bandswitch, earphone
jack. NOISE LIMITER: High performance series gate
with front panel control. POWER REQUIREMENTS:
105-125 volts AC, 50-60 cycles,.75 watts. O DIMENSIONS:
8%" H, 15%" W, 9" deep. O SHIPPING WT.: 28 pounds.
ACCESSORIES: NT-3B matching speaker, XCU-27 .1 MC
crystal calibrator. TUBE FUNCTIONS: 6BZ6 (V1), RF
Stage; 12BE6 (V2), 1st Mixer; 12BE6 (V2), HF Oscillator;
12BE6 (V3), 2nd Conversion Mixer; 12BE6 (V3), 2nd Oscillator;
12BA6
(V4), 230 KC IF Amplifier; 12BA6 (V4), Q Multiplier;
12AV6 (V6A), Detector; 12AV6 (V6B), Audio Amplifier; 6 BN8
(V7A), ANL; 6BN8 (V7B), BFO; 6CW5
(V8), Audio Output;
5Y3GT (V9), Rectifier.