For amateurs who want the latest and finest in "communication type" HF Receivers, we now offer the National AGS. The AGS has been developed in conjunction with the Airways Division of the U.S. Department of Commerce to comply with the exceedingly strict requirements of aviation ground station service.
Nothing has been omitted to make the AGS the very last word in performance and reliability
It can be shifted from CW to Voice with the turn of one control. It is equipped with optional manual or automatic-volume-control. A ground-celluloid station chart on the panel allows for easy change or erasure in listing stations. Provisions is made for either phone or speaker output.
FEATURES:
TUBE COMPLIMENT: Nine tubes are required for this receiver, exclusive of the power pack, as follows:
| R.F. Amplifier | 78 |
| 1st Detector | 77 |
| High Frequency 0scillator | 236 |
| 1st Intermediate Amplifier | 78 |
| 2nd Intermediate Amplifier | 78 |
| 2nd Detector | 273 |
| Automatic Volume Control | 236 |
| Audio Output | 89 |
| C.W. Oscillator | 236 |
The positions of the various tubes are shown in the attached plan of the receiver. It is understood that in order to secure best results tubes of recognized quality, having average characteristics, should be employed.
COILS: Four sets of band spread coils are available for the AGS receiver, covering the 20, 40, 80, and 160 meter amateur bands. These coils simply plug into the standard AGS receiver, each of the various bands being spread out over approximately 100 divisions of the dial.
ANTENNA: The antenna dimensions are not at all critical, but an antenna of average dimensions is desirable.
OUTPUT CIRCUIT: Provision is made for either headphones or loudspeaker operation by means of two sets of output terminals, located at the rear left-hand corner of the receiver chassis. The speaker input circuit is connected to the output of the 89 by means of an output filter, while the phones are connected directly in the second detector plate circuit.
CONTROLS: From left to right, the controls on the front panel are: the Intermediate Frequency Beat Oscillator Switch; Selector Switch for Manual or Automatic Volume Control; The Main Tuning Dial; Volume Control; Selector Switch for Phones or Loudspeaker
For receiving telephone or modulated c.w. signals, the beat oscillator switch is turned to "Voice", with volume controI selector switch in either position desired. When turned to the "MVC" position, the volume control is used to regulate the sensitivity or gain of the receiver. When the switch is turned to "AVC" all Signals will be held to a constant output level (within limits) with the volume control turned to the extreme right. When receiving exceptionally strong signals, the manual volume control may be used to reduce the level.
For continuous wave reception, the beat oscillator switch should be turned to the "CW" position and the volume control selector switch must be in the "MVC" position since the automatic volume control tube is practically inoperative when the beat oscillator is in use.
INTERMEDIATE FREQUENCY AMPLIFIER: The intermediate frequency amplifier is tuned to a frequency of 500 k.c., tuning being accomplished by means of the condenser adjusting screws located at the top of the Intermediate frequency transformer shield.
POWER SUPPLY: The receiver is designed for use with either the National Type GRDPU double power supply or Type 5886 AB single power supply. These units employ a series of R.F. filters for the removal of line noises, so-called "tunable hums" and similar disturbances, in addition to a carefully balanced filter for the elimination of 60 to 120 cycle ripple.
The receiver heater supply requires 6 volts at 2.7 amperes and the B supply 170 volts at 35 milliamperes. connection to the supply unit is made by means of a cord and standard 4-prong plug.
PRICE LIST:
| Catalog Symbol | Description | Net Price |
|---|---|---|
| AGS | National Type AGS Short Wave Receiver completely wired and laboratory tested, with coils to cover frequency range 1500-20,000 kc (less tubes), Bandspread coils covering 20, 40, 80 and 160 may be substituted for the same price. | $165.00 |
| RFS | National Monitor Speaker Panel employs a dynamic speaker of the permanent magnet type, requiring no power supply. Provided with impedance matching transformer and connecting cord. | $17.50 |
| CRP | National Coil Rack Panel carries receptacles for the twelve idle coils of the set of fifteen required for the National AGS Receiver. | $8.50 |
| 58C | National Standby Receiver type 58C is the well-known National SW58 arranged for rack-panel mounting, with front of panel coil changing. With 4 sets of coils. | $85.00 |
| GRDPU | 26 Rack-Panel Duplex Power Supply, for use with one type AGS and one type 58C Receiver, 105-120 Volts, 50-60 Cycle AC (less tubes) | $55.00 |
| 5886 | AB Plain Power Unit (not rack mount) for one National type AGS Receiver, 105-120 Volts, 50-60 Cycle AC (less tubes) | $21.00 |
Source: The National AGS instruction manual
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