How does the APG-79 differ from the APG-73 it replaced?

The APG-73 was a mechanically scanned slotted planar array with a single TWT transmitter. The APG-79 replaces this with approximately 1,100 individual T/R modules, each containing its own GaN power amplifier. This eliminates the mechanical gimbal, provides microsecond beam steering, enables simultaneous multi-function operation, and introduces graceful degradation. Detection range increased by approximately 50% for the same target RCS, while SAR resolution improved from approximately 3 m to sub-1 m using spotlight mode.

Radar & Defense

AN/APG-79

Q: Can the APG-79 do air-to-air and air-to-ground simultaneously?

Yes. This is called interleaved mode operation. The AESA electronically switches between air-to-air search/track beams and air-to-ground SAR or GMTI beams on a pulse-by-pulse basis, with beam repositioning times under 10 microseconds. The pilot sees both air threats and ground targets on the same display simultaneously, a capability impossible with the mechanically scanned APG-73.

Q: Is the APG-79 used on the EA-18G Growler?

Yes. The EA-18G Growler uses the APG-79 as its primary sensor, but in an electronic warfare configuration. The AESA's ability to form multiple simultaneous beams enables it to function as both a radar and a jamming transmitter. Individual sub-arrays can be assigned to different EW functions: one group performing radar search while another generates jamming waveforms against specific threat emitters, leveraging the same T/R modules for both missions.

/ay-en ay-pee-jee seventy-nine/

The AN/APG-79 is a Raytheon X-band Active Electronically Scanned Array (AESA) radar system designed for the F/A-18E/F Super Hornet and EA-18G Growler. It features approximately 1,100 GaN T/R modules arranged in a circular aperture, providing simultaneous air-to-air search/track, air-to-ground SAR imaging, GMTI, and electronic attack capabilities through pulse-by-pulse beam interleaving. The APG-79 replaced the legacy APG-73 mechanically scanned radar, delivering approximately 50% greater detection range, sub-1 meter SAR resolution, and the ability to perform radar and jamming functions simultaneously from the same aperture.

Category: Radar & Defense

Platform: F/A-18E/F, EA-18G

T/R Modules: ~1,100

Understanding the AN/APG-79

The APG-79 entered service in 2007 as one of the first production fighter AESA radars. Its circular aperture, approximately 70 cm in diameter, houses ~1,100 T/R modules at half-wavelength spacing (~15 mm at X-band). Each module contains a GaN power amplifier (5-10 W), GaAs LNA (1.8 dB NF), 6-bit phase shifter, and T/R switch, with liquid cooling provided by a cold plate directly behind the array face.

The radar's key advantage over the legacy APG-73 is interleaved multi-function operation. The electronic beam steering time is under 10 μs, allowing the radar to alternate between air-to-air and air-to-ground modes on consecutive pulses. The pilot sees a fused display showing both airborne threats and ground targets simultaneously, without any interruption to either function.

APG-79 Performance Parameters

Array gain:
G = η·4πA/λ²
A ≈ π(0.35)² = 0.385 m², λ = 0.03 m
G ≈ 0.6 × 4π(0.385)/(0.03)² ≈ 34 dBi

Total transmit power:
P_t = N × P_module = 1100 × 8 W ≈ 8.8 kW

SAR resolution:
Δ_cross-range = D/(2) ≈ 0.35 m (spotlight mode)
Δ_range = c/(2B) for waveform bandwidth B
Sub-1 m resolution in both dimensions

US Fighter AESA Radar Comparison

Radar	Platform	T/R Modules	Aperture	Manufacturer
AN/APG-79	F/A-18E/F, EA-18G	~1,100	70 cm circular	Raytheon
AN/APG-81	F-35A/B/C	~1,200	80 cm	Northrop Grumman
AN/APG-83 SABR	F-16V	~1,000	55 cm	Northrop Grumman
AN/APG-82(V)1	F-15EX	~1,500	91 cm	Raytheon

Common Questions

Frequently Asked Questions

How does the APG-79 differ from the APG-73?

APG-73 used a mechanically scanned slotted array with a single TWT. APG-79 replaces it with ~1,100 T/R modules, eliminating the gimbal, providing μs beam steering, simultaneous multi-function operation, and graceful degradation. Detection range increased ~50% and SAR improved from 3 m to sub-1 m.

Can the APG-79 do air-to-air and air-to-ground simultaneously?

Yes. Interleaved mode switches between A/A search/track and A/G SAR or GMTI beams on a pulse-by-pulse basis with <10 μs repositioning, showing both on the same display.

Is the APG-79 used on the EA-18G Growler?

Yes. The Growler uses APG-79 for both radar and EW. Sub-arrays can simultaneously perform radar search while other sub-arrays generate jamming waveforms against specific emitters.

Related Terms

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