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Similarly to other upgrades and new tools already mentioned in this series, such as DSCG or TISEO, the AN/ALQ-120 was upgraded through the years. Three main configurations were adopted, at least until the mid-80s.
Radar Evolution
The oldest is the AN/APG-120D(V), and it is the basic radar set. It is the aeroplane shown in the footage I am recording in FSX, and uses the older DVST display, or Direct View Storage Tube.
The AN/APQ-120F(V) is the successor, and different blocks host different features. In general, the TISEO camera set was installed and, in such cases, the newer DSCG, acronym for Digital Scan Converter Group, display was used. On top of the DVST functionalities, the display sets are TV capable, and can provide azimuth and elevation drive commands to TISEO and AGM-65 seekers.
Finally, the AN/APQ-120(V) dash 10 and dash 11, provided the new and improved Computer Automatic Acquisition (or CAA) mode. A dedicated ground programmable computer provided accurate launch envelopes for the aim-7E and 7F Sparrow, aim-9P 2, 3 and N 2 and 3 missiles.
Radar Controls: The Radar Set Control Panel
Most of the radar controls are located in the back seat, the WSO’s office. Some controls have been mentioned already, but I will discuss them again for completeness’ sake. If you haven’t already, I recommend checking the previous part of this series, dedicated to Air-to-Air missiles and related controls.
As the name suggests, The Radar Set Control Panel, hosts several controls related to radar operations.
Radar Power Knob
Starting from the top-left corner, we find the Radar Power Knob. Skipping Off and Test options, we find the Standby position. This setting maintains the radar in ready condition, minimising the time necessary to switch to full operation. It would take circa three minutes, in fact, to move from “Off” to Operate, instead.
The standard employment mode is Operate, indicated by the acronym “OPR”. In this setting, the system is fully operational.
Emergency is the last option, and bypasses most of the initial delay, and pressure and temperature interlocks.
Polar Switch
Moving clockwise, we find the Polar Switch, a 3-way switch that controls the polarisation, and therefore the orientation of the lines of electric flux in the electromagnetic field.
“Lin” short for “Linear”, is a standard option, and it is normally used to employ the AIM-7 Sparrow.
“Cir 1”, or “Circular 1” rotates the RF energy clockwise, and still allows the employment of the Sparrow.
Finally, “Cir 2” or “Circular 2”, is automatically commanded when the radar is in “Beacon” mode. However, AIM-7 Sparrows cannot be employed in this mode, as the waves are out of phase.
Radar Range Knob
The radar range knob is straightforward, with the peculiarity that the ranges between 5 and 50 are clearly marked and separated from the values 100 and 200. The reason is that those 4 initial positions are AI, acronym for Air Intercept. When selected, the corresponding range light is activated in the cockpit.
100 and 200 nautical miles are instead used for search or mapping, but there are some peculiar cases, as we will see later.
In DSCG Phantoms, the range is also displayed on the scope.
Manoeuvre Switch
The manoeuvre switch is a 2-position control used to control the tracking loop responses. The “Low G” option limits the acceleration responses to clutter and countermeasures, whereas “High G” is better suited for air-to-air combat.
Note that, when CAA is used, High G is selected automatically.
Scan Switch
The number of bars scanned by the radar is selected via the “Scan switch”. The WSO can either select one or two bars, which is a bit of a shock coming from the eight bars of the AWG-9.
However, the radar follows a particular circular pattern in specific situations we will discuss in the next parts, which enlarges the volume scanned by the beams to 6.7°. This volume surpasses 4 bars in the AWG-9. When 2 bars are selected, the volume is 10.45°, which is quite close to the 8 bars setting of the Tomcat’s radar.
Here is a curiosity: if you follow 10% True, Steve Davies’ Discord and YouTube channel, you may have watched the walkthrough of the F-4G EWO cockpit. Since this aircraft is a conversion of the F-4E, some parts, such as the panel we are discussing, have been maintained. In that video, Starbaby mentioned how, in real life, the switch was always set to 1 bar. I asked him about it, and the issue is related to how, among other things, 2 bars turn the contacts into intermittent hits, making them harder to spot.
Away from that, the 1 bar option is automatically selected in air-to-ground or map modes. Otherwise, 2 bars can be chosen, which adds another scan plane, separated by 3.75°. In both cases, the elevation angle is adjustable using the thumb wheel located in the antenna hand control.
Aspect Knob
The aspect knob is used with the AIM-7 Sparrow. A similar knob is located in the F-14 Armament Panel, but it is not implemented in DCS, due to the game’s restrictions. The purpose of this control is feeding information to the Sparrow, providing a predetermined and simulated Doppler value, rather than actual inputs.
The knob is used after the missile tuning, and the four positions between Nose and Tail allow to lock the missile speedgate in the region of the target Doppler. Wide behaves differently: if selected, the speedgate searches the entirety of the spectrum, overriding other Doppler inputs.
Depending on the version of the F-4E in use, the knob serves the dual purpose of showing different values rather than only the range on the scope, as we have discussed earlier.
In particular, the Nose position shows the Target Aspect Angle and the Altitude, displayed in hundreds of feet, using different time length to discern them: the altitude is displayed for 2 seconds, the Aspect for 4 seconds.
In other older versions of DSCG Phantom, the Aspect is displayed using the Nose position, and the Altitude using the Forward option. The Tail position shows the approximated target heading.
Receiver Gain Knob
The receiver gain knob, quite an odd-looking one, it is used to adjust the gain of the radar in certain operations, and it is automatically bypassed when tracking a target.
Track Switch
The Track Switch is an interesting one. This 3-position switch, allows the WSO to compensate for heavy clutter environment by manually performing radar tracking operations.
When set to Auto, as the name suggests, range and angle tracking are performed automatically. If the target is manoeuvring beyond the radar tracking capabilities, the WSO can action the Manoeuvrer switch to compensate.
The Manual position sounds like a lot of fun: the WSO initiates manual tracking and positions the range strobe in-range from a closing-target, then adjusts the Manual VC control to match the target video moving range. It is basically something in-between Space Invaders and Tetris…
The last option is AOJ Out, where AOJ stands for Acquisition on Jamming. This feature allows a source of noise or jamming to be automatically tracked in angles when in search mode. This position of the switch disables AOJ, returning the radar to a search configuration.
Display Knob
The Display Knob controls both the perspective and the azimuth of the display.
In B mode, the WSO can manually control the sweep using the half-action on the trigger switch, something similar to the DDD. The difference between Wide and Narrow is the width of the radar swept volume. Wide corresponds to 120°, Narrow to 45°.
PPI stands for Plan Position Indicator. They share the sweep volume with the B modes, but there are differences. PPI Wide is used along the radar in Map mode. Narrow instead can be manually positioned in azimuth by the WSO, and also provides a range cursor for mapping or bombing purposes.
VI, or Vis-Ident, functions differently depending on the upgrade of Phantom in use, and I’d rather discuss it later when the F-4E is released. Generally speaking, it provides pure pursuit steering towards the target, but there are some caveats.
Manual VC Control Knob
The Manual VC Control Knob, or Man VC, is the oddest control on the Radar Set Control Panel, resembling the timer of a Toaster rather than a piece of avionics of a mean fighter jet.
This tool is, however, essential to operate the radar in manual mode. If the range rate is “opening”, ergo the separation is increasing, the VC control is rotated counterclockwise, from position 0 through 2, otherwise the others.
As mentioned before, the idea is using this control along the radar set in Manual. The WSO should spotlight the target using half-action, position the strobe slightly below the target, ergo a bit closer to the Phantom, then use full-action. The range is then extrapolated as a function of the position of the range strobe, whereas the closure rate is manually set using this control. The WSO should carefully try to match the closure with the correct knob setting and make sure that the target video and the range strobe are moving in the same direction. When the correct setting for VC is determined, the WSO should use half to overlap the range strobe to the target, and then press full action and release.
Something I noticed, is that the range rate indicator has a series of numbers, arranged on the outer circle in a comparable manner. If that is the case, this would help to get a feeling of the correct values to input.
I honestly do not know in what cases the radar in manual mode should be operated, but it sounds like a ton of fun already!
We have only three controls still left to discuss in this panel, so let’s quickly see them.
Pulse Switch
The Pulse Switch is a 3-position switch that controls the radar pulse width and the pulse repetition frequency. The default mode of operation is Auto, and the switch has no function when the radar is in Air-Ground mode, as we will see later.
The other two options are Long and Short. Long allows greater detection range by setting low PRF and wider pulse, but makes the radar less capable of discerning multiple contacts on the same bearing.
Short instead is used for AI ranges and has higher PRF. This mode increases detection capabilities at shorter ranges.
Skin Track Light
The Skin Track Light indicates tracking with range lockon. If range memory or Home-On-Jam tracking are active, the light remains off.
Radar Mode Knob
The last control is the Radar Mode knob. This 6-position knob allows the WSO to select the main radar modes of operation. Each mode also has a number of submodes, but those will be discussed later.
Clockwise, we find the “BST” position, or Boresight Mode. This mode is used in both search and acquisition, and the antenna is set to 0° azimuth, and -2° of elevation. The idea is using the sight reticle to match the target, and then lock it. After this, the fighter can manoeuvre freely.
“RDR”, or Radar Mode, enables air-to-air radar search functions, and lockon and tracking if the range is between 5 and 50 nautical miles. This mode represents familiar indications to the WSO, such as the aircraft attitude or the elevation strobe. On top of that, the B-Sweep is displayed. Somewhat similarly to the DDD, this line moves in conjunction with the radar antenna.
The Radar Mode allows the WSO to use half and full action to acquire a target and employ missiles. There are additional sub-modes initiated, for example, when jamming is present, but those will be discussed in a later part.
The next option is “Map B” Mode, and it is used when conducting search operations at low altitude. Since we cannot take advantage of Pulse Doppler, understandably, clutter becomes a problem. This mode tries to reduce the issue by concentrating the antenna beamwidth, which should provide higher target resolution. Moreover, “Map B” Mode overrides other controls, placing the radar to 1-bar, with linear polarisation.
“Air-GRD” or “Air to Ground” mode provides radar range to non-discrete targets, and requires a radar range set within the AI bracket, therefore between 5 and 50 nautical miles.
This mode allows automatic range tracking by superimposing the radar to the optical sight pipper, and then locking as usual. This will make more sense when we will discuss air-to-ground procedures.
“Beacon” mode is quite peculiar, as the radar displays signals from ground or airborne beacon transponders, providing navigational information.
Lastly, the TV, or Television mode, is used along the AGM-65 Maverick. It is fundamental to keep in mind that AIM-7 Sparrow missiles are detuned and cannot be tuned when the Radar Mode knob is in this position.
Besides this panel, there are additional controls discussed in previous parts, such as the VC switch and the Stab switch located in the Monitoring panel, just North or the Radar Set Panel, or the Antenna Control Handle.
This concludes the first phase of the F-4 familiarisation series, heavily focused on the instrumentation and the avionics, mostly for air-to-air operations. This has been a necessary step, as going forward, we will focus on more details, such as radar patterns and nutation, radar “sub-modes”, for the lack of a better description, and much more.
FlyAndWire 