AGS-X
This radio is a 1932 or 1933 National AGS-X shortwave receiver. The AGS-X is a 9 tube superhet covering 2.4 mhz to 20 mhz. It covers this range by using 5 sets of
plug-in coils, and each set has 3 coils. They are identified A1,A2,A3, B1,B2,B3, etc. AGS stands for Aeronautical Ground Station, and they were originally built for
use by the airline industry. It was one of the first high performance superhets commercially available. The AGS-X has a crystal filter, and bandspread coils were
available for the amateur community. But because of its high cost and the depression, few found their ways into ham stations (about $295 for the AGS-X vs about $27 to $40 for an FB-7).
Supplementary photos
HRO Junior
National HRO Junior manufactured in mid 1937. The Junior did not initally come with a S meter but after WWII National offered to install S meters in Juniors and many Hams
had them installed. The radio has 2-1/2 v tubes (6 v tubes can be substituted without any circut changes). The Juniors came with non band spread coils and the coil window was
in the center of the coil. Senior band spread coils can be used.
Supplementary photos
HRO Senior
National HRO Senior manufactured later 1930s.
Supplementary photos
NC-46
National NC-46 receiver built from 1945-1947. It has four bands and covers .55-30 Mhz. The IF frequency is 455 KHz. It uses 10 tubes that are series strung (no power transformer).
The output tubes are two 25L6 in push pull, which gives about 3 watts of audio. The receiver is un-restored but I see a few capacitors that have been replaced as well as a replacement audio
output transformer. The NC-46 required an external 8 ohm speaker. Ten tubes in an advanced superheterodyne circuit provide excellent sensitivity throughout the receiver's range
from 540KC to 30 MC. Circuit features include an amplified and delayed AVC, series valve noise
limiter with automatic threshold control, CW oscillator and separate RF and AF gain controls.
The push-pull output provides 3 watts power, and the AC-DC power supply is self-contained.
TUBE COMPLIMENT:
FREQUENCY RANGE: The Frequency Range of the NC-46 Receiver is 540. Kc. To 30. Mc. covered in four bands.
CONTROLS: Main Tuning Dial; Bandspread Tuning Dial; Sensitivity Control; Volume Control; Tone Switch; C.W. Oscillator Switch; AVC Switch; Limiter Switch; Band Selector Switch; B+
Switch and Power Switch. TERMINALS: On Rear Panel; Phone Jack; B+ Terminals; 8 Ohm Spkr. Terminals; Ant. Terminal; Fuse extractor post.
SENSITIVITY: Approximately 5 microvolts input provides a 50 Milliwatt output over the entire range, SELECTIVITY: The total bandwidth is approximately 4.5 Kc. at 6 db. down and approximately
70 db. attenuation 10 Kc. off resonance is obtained. POWER INPUT: Operation from 110/130 volts A.C. or D.C. Normal power consumption 65 watts.
POWER OUTPUT: Approximately 4 watts undistorted. PHYSICAL DATA: NC-46 Receiver: 9 7/16" high by 17 3/8" wide by 12 3/8" deep, Weight 32 lbs., Gray Wrinkle Finish. NC-109
TUBE COMPLIMENT: RF Amp. 6BA6, Freq. Conv. 6BE6, HF Osc. 6C4, 1st IF Amp. 6BA6, 2nd IF Amp. 6BA6, 1st AF and BFO/S meter amp. 12AT7, AF Output 6AQ5, Rectifier 5Y3GT, Voltage Regulator OB2, Product Detector 6BE6, AVC and ANL 6AL5.
CIRCUIT DESCRIPTION: Eleven vacuum tubes, including a rectifier and a voltage regulator, are
used. A superheterodyne circuit is used in which signals from the RF amplifier and local oscillator
are heterodyned in the mixer producing a 455 kc IF signal. This mixer product is then amplified by
two audio amplifier stages to a sufficiently high level to drive a loudspeaker or headphones. The
crystal filter provides six degrees of selectivity. Bandwidth of the crystal filter varies form 3.8 kc to
50 cycles at 6 db points over the six positions of the Selectivity switch. A product detector is used
for signal sideband and CW reception. An extremely stable CW oscillator is used for carrier
injection.Sufficient oscillator stability for single sideband reception is ensured by power supply
regulation and careful circuit design.
TUNING SYSTEM: Separate general coverage and bandspread tuning capacitors connected in
parallel on all bands. Bandspread, used primarily for tuning the amateur bands, can be used as a
vernier for general coverage use. Antenna trimmer is on the front panel.
COVERAGE:
AUDIO SYSTEM:
A handsomely styled accessory speaker NTS-1 is available.
OTHER SPECIFICATIONS:
Supplementary photos
FEATURES: Calibrated bandspread for 10, 11, 15, 20, 40 and 80 meter amateur bands. Separate tuning capacitors, knobs, and scales for general coverage and bandspread.
Large 12 inch indirectly-lighted lucite slide rule dial.
Adequate over-all selectivity with eleven miniature tubes including rectifier and voltage regulator.
Has exclusive "microtome" crystal filter providing five degrees of sharp selectivity in addition to normal bandwidth for voice, has sharp phasing notch over 60 db deep for interference rejection.
Separate product detector for excellent reception of CW and SSB Signals.
Has "S"meter on front panel for signal strength indication and more accurate tuning.
Separate high frequency oscillator tube increases stability. Has ceramic oscillator coil forms and is temperature compensated for exceptional stability.
BANDGENERAL COVERAGEBANDSPREAD
A.54 - 1.6 mc
B1.6 - 4.7 mc3.5 - 4.0 mc (80 meters)
C4.7 - 15.0 mc6.9 - 7.3 mc (40 meters)
D14.0 - 40 mc14 - 14.35 mc (20 meters)
20.4 - 21.5 mc (15 meters)
27 - 30 mc (10/11 meters)
Two-stage audio amplifier with single 6AQ5 output tube provides 1.5 watts at less than 10% distortion.
Output impedance 3.2 ohms.
Has phone jack.
DRIFT: .01% or less.
SENSITIVITY: Under 1-2 microvolts (10db signal/noise ratio).
SELECTIVITY: 6 positions.
Constant Gain.
NORMALSHARP
6 db5.2 kc200 cycles
60 db29.5 kc10 kc
Antenna Input: 50-300 ohms, balanced or unbalanced. Size: 16 3/16" Wide x 10" High x 10 7/8" Deep. Finish: Handsome Two-tone gray wrinkle finish
Supplementary photos
NC-156
National receiver NC-156. Tunes from about 300 kc to 16 mc. It weights about 60 pounds.
Supplementary photos
NC-200
NC-200. NATIONAL 200 TRANSCEIVER MANUFACTURED BY THE FORMER (NC) NATIONAL RADIO COMPANY MELROSE MASSACHUSETTS.
IT IS A 5 BAND HIGH PERFORMANCE TRANSCEIVER COVERING 80,40,20,15 AND 10 METER'S IN 3 MODE'S SSB/AM/CW. INCLUDING THE
CALIBRATOR IT UTILIZES 18 TUBE'S, 12BA6 1ST IF, 12BA6 2ND IF, 2 12AX7'SPRODUCT DET, AM DETECTOR,AUDIO AMP,6AQ5 AUDIO OUTPUT,
2 6GH8'S,MICROPHONE-PREAMP-S-METER,12BA6 CARRIER OSCILLATOR, 12BA6 BALANCED MODULATOR, 2 6GH8 PRE-MIX, XTAL OSC, 6JD6 TRANSMIT MIXER,
6GK6 DRIVER, 2 6GJ5'S FINAL AMPLIFIER. RF POWER OUTPUT IS 120 WATT'S PEP SSB,120 WATT'S CW, 30 WATT'S AM. SOME FEATURE'S INCLUDE M
IC GAIN/CAL CONTROL,R F GAIN CONTROL,AF GAIN CONTROL, MIC JACK, ON/OFF/SSB/AM/CW/TUNE FUNCTION CONTROL, MAIN TUNING DIAL, PA TUNE CONTROL,
28.0/21.0/14.0/7.0/3.5 BAND SWITCH,PA LOAD CONTROL,MOX SWITCH,EXCITER TUNE CONTROL. ON THE BACK PANEL ANTENNA JACK, BIAS ADJ,POWER
SUPPLY JACK, CALIBRATOR JACK, EXT ALC IN JACK,PHONE AND KEY JACK'S, RELAY TERMANAL, CARRIER INSERTION CONTROL + MORE. THE DIMENTIONS
ARE ;6 3/16"H,13 3/8" W,11" DEEP. WEIGHT NOT INCLUDING THE P/S 15LBS.
Supplementary photos
NCX-500
National NCX-500 SSB Short Wave Transceiver. Specs: 500 watts PEP SSB; 390 watts CW; 125 watts AM. (USB on 20, 15, & 10 meters, LSB on 80 & 40 meters), AM, CW.
Output impedance is 40-60 ohms/Pi Network. Full AGC and S-meter on receive; Dial calibration is 5khz. 45:1 tuning ratio on all bands. Freq. stability 1500 Hz first 30 min,
Long term stability 400 Hz in room ambient conditions. Carrier suppression -50db, unwanted SB -40, 3rd order distortion -30db at full output.
Sensitivity of Rcvr: .5uv for 10db S/N in SSB mode. Audio output more than 2 Watts into 3.2ohm speaker.
Supplementary photos
NCX-1000
National NCX-1000 SSB Short Wave Transceiver. Specs: 500 watts PEP SSB; 390 watts CW; 125 watts AM. (USB on 20, 15, & 10 meters, LSB on 80 & 40 meters), AM, CW.
Output impedance is 40-60 ohms/Pi Network. Full AGC and S-meter on receive; Dial calibration is 5khz. 45:1 tuning ratio on all bands. Freq. stability 1500 Hz first 30 min,
Long term stability 400 Hz in room ambient conditions. Carrier suppression -50db, unwanted SB -40, 3rd order distortion -30db at full output.
Sensitivity of Rcvr: .5uv for 10db S/N in SSB mode. Audio output more than 2 Watts into 3.2ohm speaker.
Supplementary photos
NTS-1
National NTS-1 speaker. This is the matching speaker for the National NC-109.
Supplementary photos
SW-3
National SW-3 "Thrill box", a real classic short wave receiver from the mid 1930s, six pin tubes.
Supplementary photos
