Delta Electronics RG-4 Receiver/Generator

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  • Up to 2 Watts Output
  • 5 Microvolt Receiver Sensitivity
  • 120 dB Receiver/Generator Isolation
  • 100 kHz to 29.999 MHz Operating Range
  • Digital Frequency Synthesizer Design
  • Easy Keypad Entry Operation
  • 9 Frequency Storage Registers
  • Coincidence Detector
  • Large LCD Frequency Display
  • Battery Pack for Portable Operation

The RG-4 Receiver/Generator is Delta’s newest model in its continuing line of precision RF generators and null detection receivers for impedance bridges. The RG-4 is designed as the ideal companion instrument for Delta’s OIB-1 and OIB-3 MF Operating Impedance Bridges and the OIB-2 HF Operating Impedance Bridge. These bridges and the RG-4 form a complete portable impedance measuring system.

The RG-4 operating frequency range is from 100 kHz to 29.999 MHz in 1 kHz steps. The generator output is adjustable to 10 VRMS (2 Watts), 100 kHz to 20 MHz, and 4 VRMS (0.3 Watts) above 20 MHz. Receiver sensitivity is 5 microvolts with separate front panel gain controls for RF and audio levels. Generator to receiver isolation is greater than 120 dB.

In noisy environments or under conditions of interfering signals, the generator can be modulated by an internal 50 Hz squarewave and the receiver’s coincidence detector circuit will provide clean positive nulls. The generator can also be modulated by an internal 400 Hz signal at 90% modulation. When operated in this manner, the receiver provides both visual and audible null indications.

Frequency selection is accomplished by a front panel keypad which controls a precision phase locked loop digital frequency synthesizer. The operating frequency is displayed on a large LCD front panel readout. To expedite field tests, nine storage registers provide recall of frequently used frequencies. Frequency increment and decrement keys provide manual sweeps of a chosen frequency in 1, 10, 100 or 1000 kHz steps. Separate 5 kHz increment and decrement keys simplify FCC required antenna impedance sweeps. Rechargeable batteries power the unit for field measurements for two and a half hours minimum at full RF output. The AC supply/charger operates from either 120 or 240 VAC. The power supply will both power the unit and charge the batteries at the same time. Automatic switching to a “trickle” charge mode maintains full charge without battery damage. The lightweight construction combined with a rugged weatherproof aluminum case make this instrument equally at home on the service bench or in the field.



The RG-4 is designed to be used in conjunction with any conventional impedance bridge for antenna measurements in the AM Broadcast and HF bands. A dramatic improvement in signal-to-noise ratio will be realized when the RG-4 is used with the Delta Model OIB-1, OIB-2 and OIB-3 Operating Impedance Bridges. The patented circuit of the OIB series of impedance bridges places the high level generator output directly in parallel with the interfering signals on the antenna.

With conventional bridges, the generator is attenuated by the measuring network of the bridge before competing with any interfering signals. Such operation can make nulling of the bridge difficult.

Interference problems are virtually eliminated using the RG-4/OIB combination. The excellent generator to receiver shielding and the dramatic improvement in the signal-to-noise ratio makes the RG-4/OIB combination the consultant’s choice for either HF or broadcast antenna impedance measurement applications.

Technical Specification

Technical Specification

Frequency Range: 100 kHz to 29.999 MHz in 1 kHz steps

Generator/Receiver Isolation: Greater than 120 dB


Output: 100 kHz to 20 MHz, Adjustable to 10 VRMS (2W) into 50 ohms

20 MHz to 27.5 MHz, Adjustable to 5 VRMS (0.5W) into 50 ohms

27.5 MHz to 29.999 MHz, Adjustable to 4 VRMS (0.3W) into 50 ohms

Modulation: 400 Hz 90% AM, 50 Hz squarewave

Output Connector: BNC Female


Type: Dual Conversion Superheterodyne with AGC

Sensitivity: 5 µV Nominal

Selectivity: -3 dB Bandwidth: 3.8 kHz

-45 dB Bandwidth: 18 kHz

BFO: On/Off, 455 kHz ±5 kHz

Audio Output: Internal speaker or headphone connected to front panel phone jack

Input Connector: BNC Female


Battery (BAT) Battery or power supply voltage

Generator (GEN) Generator output in VRMS

Receiver (RCVR) AGC level or coincidence detector output

Charging LED: Illuminated during battery charging, flashes during trickle charge mode

Power: Battery Operation – Two Gel/Cells® (or equivalent)

Operating Time (Full Charge) – 2.5 hours nominal at 68° F

Recharge Time – 6 hours nominal

Line Operation – 120/240 VAC ±10%, 47/63 Hz, 35 Watts

Temperature: Operating: 0° C to +40° C

Storage: -10° C to +60° C

Size: 13.5″ W (343 mm) x 8″ D (203 mm) x 12″ H (305 mm)

excluding carrying handle

Weight: 23 pounds (10.5 kg) with batteries

Order Numbers: RG-4 with 120 VAC Power Supply: 915-0011-001

RG-4 with 240 VAC Power Supply: 915-0011-002

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