APQ-50/72/100/109/120 detection range?

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lancer21

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Hello everyone , new user , happy to be here! Great site , been following it for quite a while, and decided to join, so much interesting info and discussions here!

Now, as my topic title suggests , i'd like to ask if someone has some datas on these radars, at least some summary data on their detection range against fighter and bomber RCS targets ? Surprisingly, even if the F-4 is an old bird, cant find much reliable info on its various radars, tried few places , but no luck so far.

Also , if i understand correctly , none of the above radars have LD/SD capability , except the AWG-10/11/12 sets, right ?( and if anyone have dats on their characteristics too , i'd be grateful)

Thank you for your help!
 
Well after alot of browsing , i did found a good old harpoon PDF document containing various radar data ...its not 100% accurate , but thats all i got , i read there that the APQ-120 is credited with a max detection range of 50nm, and the APQ-100/109 with 40nm...i'll just post what i got, harpoon gives the range for various size target ( large, medium , small , v. small in that order )

APQ-120 AI 50/35/26/11/3
APQ-100 AI 40/25/19/8/2
APQ-109 same

...is anyone able to confirm these datas please? Thank you.

BTW extermely surprising that harpoon credits Cyrano-IVM with JUST 30nm !!! but thats another issue...
 
I know but thats all i could find on the bloody things! :D

( save for something from our good russian friends comunity ...but even there the information is contradictory ...so its still open )
 
Interesting info , thanks. :)
Would you have a source for this info please?


I have been looking around on various russian boards for info on these radars , i found some unconfirmed fugures for the APQ-120 , for instance detection range for a 1m2 RCS target being 56km!( 30 nm-incidentaly this info is published in VERY old Flight Global magazines , at the end of seventies...). Other infos state the detection range for a FIGHTER size target is 70km , while still other info states that this 70km figure refers to a BOMBER size target detection range ...

Gee what is so secret about this radar that one cant find any reliable info around ... ???
 
1) targets vary in RCS at different angles

2) detection range varies in different conditions

3) detection of targets is not 100% reliable.

4) performance of analogue radars depends on how well they are tuned and maintained.

Its not like the target is at 90.1km away and you definitely can't detect it, but then next sweep its at 89.9km and you can detect it with 100% certainty. Radar X might have 10% chance of detection for a given size target at 90km, 50% chance of detection at 70km, 90% chance of detection at 50km. If you wanted, you could claim it has a range of anywhere between 50km and 90km - do you go with the maximum possible range, the average range, or the range where you can be almost certain to detect the target?

Westinghouse brochures for the APG-66 quoted range for a 90% chance of detection, but when the figures were repeated elsewhere, most writers used only the range value. If a rival company wanted their radar to appear superior, they could quote the range for 50% chance of detection, or quote the maximum range ever seen during testing, and seem to have a longer range radar, but it might not be really any better.

So finding a single agreed range figure is a fruitless task....
 
Thanks for your reply Overscan , yes you do have a point offcourse. As i mentioned before in another topic i dont know much about the technical stuff ( klystron tubes ,waveguides and the likes) , but i'm just an enthusiast( fanboy? ) who likes to learn and know things about ones hobby...

Lets just say i'm just looking for the sort of info on detection ranges for APQ-120 and other Phantom radars, like you have ( had ?) on your russian avionics site for various russian radars, from a decently reliable source ... :)

Thanks again.
 
Conical Scan or Monopuls

APQ-50/72/100/109/120

Do they still using conical scan or are these monopuls radars?
 
Hehe, after a year i got into the "Phantom radars" fever again. ;D

It's late, but may i ask , is the above reply ment to me or the poster above ( i did go thru the AWG-10 topic , although in all honesty i don't understand 90% of the technical stuff posted there. :-[ Off course i did found the 60nm vs 5 sqm RCS target range figure, quite impressive for those years i guess).
 
overscan said:
Its not like the target is at 90.1km away and you definitely can't detect it, but then next sweep its at 89.9km and you can detect it with 100% certainty. Radar X might have 10% chance of detection for a given size target at 90km, 50% chance of detection at 70km, 90% chance of detection at 50km. If you wanted, you could claim it has a range of anywhere between 50km and 90km - do you go with the maximum possible range, the average range, or the range where you can be almost certain to detect the target?

Westinghouse brochures for the APG-66 quoted range for a 90% chance of detection, but when the figures were repeated elsewhere, most writers used only the range value. If a rival company wanted their radar to appear superior, they could quote the range for 50% chance of detection, or quote the maximum range ever seen during testing, and seem to have a longer range radar, but it might not be really any better.

So finding a single agreed range figure is a fruitless task....
Click to expand...
overscan, when you talk about the probability of detection, is this based on a single sweep?

Thanks
 
Detection limits, A/N APQ-109:

A/A search/aquisition B-sweep: 40 nm (if memory serves)
A/G PPI-sweep: 200 nm

I suppose the reason for the short A/A range is the low power/high prf rate upon target lockon. With the old conical scan sets, the high prf and short pulse of the locked-on mode allowed accurate angle, range and range rate tracking.

Regarding LD/SD, the set could certainly look down, but missile firing solutions for old-school AIM 7's & AIM 9's calculated by the A/N APA-165 system didn't allow much angle deviation. Regarding A/G missiles and smart bombs, the F4 C/D platforms were pretty robust, and allowed for many mods to accommodate a wide variety of fire control modalities which integrated with the A/N APQ-109.

I guess this has been de-classified by now...right?
 
I was a radar technician stationed in Thailand during the Vietnam war. I was testing out operation of a system on the flight line, something I didn't have very many opportunities to do. Using the B sweep mode set for a hundred miles range I picked up a Target about 70 miles out which I can only assume from its size was a B52. I locked on and tracked him approximately 2 to 3 minutes before I was jammed by electronic countermeasures.
 
Here are some extracts from the F-4E plus contract summary (credit Ron Downey via Aviation Archives): http://aviationarchives.blogspot.com/2016/01/f-4e-plus-contract-proposal-summary.html

It lists the performance McDonnell Douglas was willing to guarantee for the AN/APQ-120 radar system. This is obviously from before the F-4E entered service, so it is unclear how the radar actually performed against these guarantees, but I thought I would share it as it's the first official(ish) numbers I've stumbled across for AN/APQ-120 performance.

The contract proposal also mentions the Coherent On Receive Doppler System (CORDS), which was meant to provide look-down capability for the F-4E. In practice they could never get CORDS to work reliably so development of it got scrapped 1968.
 

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I have found some good info in a declassified pdf about the Have Doughnut MiG-21 testing. Real world average detection range for APQ-109/120 head on vs MiG-21 is 20nm aquisition and 15nm tracking, from tail-on is 25/17, and from abeam is 35/28.

Edit: According to the report, APQ-109 has a 5-10% range detection/tracking advantage re the APQ-120 (so annoyingly for me they haven't listed separate figures for 109/120, just averaged the figures as shown above)

There is also info for APQ-72 and APG-59, but have to study those chapters later (i'm way late into the night perusing that report)
 
Last edited:
I've edited above with some additional info.

Figures for APQ-72 are:

At low to medium 5000- 15000ft altitude, detection at max 32nm, average 20-25nm. Tracking at max 18nm, average 15nm.
At medium to high 15000-30000ft altitude, detection at max 40nm, average 30-35nm. Tracking at max 27nm, average 25nm.

For APG-59, in pulse mode figures (not mentioned) were slightly less compared to APQ-72, the latter was a bit better at high alt, while the former a bit better at low alt.
APG-59 in pulse-Doppler mode, front quarter average detection in excess of 45nm, with a maximum of 62nm. Couple of tests resulted in the MiG being detected, aquired and tracked at 50nm and 15,000ft.
 
Having found out these very interesting figures, i'm wondering now if there's any info as to the weight of these radars? I've read somewhere that the APQ-120 weighs 290kg (approx 640lb), while in the AWG-10 topic it says that radar weighs between 650 and 750lb (340kg), not sure why the weight difference.

Really, the reason i'm trying to find this kind of info is that i want to find out how contemporary american and soviet radars compare ( i'm not knowledgeable into the deep technicals of it, so the basic numbers like range weight etc have to do for me), i'm trying to compare apples to apples as much as possible. Very interesting the 3 different detection range aspects for the APQ-109/120, namely head-on, tail-on and beam-on, each showing successively longer ranges.

Perhaps diverting a bit too much here, but does anyone know if the pretty well known russian radar ranges figures (for radars like S-23, Oryol, Smerch etc) refer to head on aspect and are they average figures, in which case should it be assumed that tail-on or beam-on figures should be roughly increased as for the APQ-109/120, and same for maximum possible ranges?
 
The F4D AN/APQ 109 - AN/APA 165 RADAR package consisted of the following components (to the best of my faded memory): RT & CW units, synchronizer, modulator, power supply, TIC, antenna, antenna manual controller, RADAR system pressure pump, display electronics, HUD, front & back screens. I'm just guessing, but all these components must have weighed in at about 650 lbs. (I have no guess on the weight of the mounting infrastructure & hardware.)
 
lancer21 said:
Perhaps diverting a bit too much here, but does anyone know if the pretty well known russian radar ranges figures (for radars like S-23, Oryol, Smerch etc) refer to head on aspect and are they average figures, in which case should it be assumed that tail-on or beam-on figures should be roughly increased as for the APQ-109/120, and same for maximum possible ranges?
Click to expand...
Head-on unless otherwise specified.

Beam-on range is normally higher because RCS is higher, but flying 90 degrees to your target isn't a great interception tactic and its bad for pulse-doppler radars.
 
lancer21 said:
Having found out these very interesting figures, i'm wondering now if there's any info as to the weight of these radars? I've read somewhere that the APQ-120 weighs 290kg (approx 640lb), while in the AWG-10 topic it says that radar weighs between 650 and 750lb (340kg), not sure why the weight difference.
Click to expand...
AWG-10 is a much more advanced radar using Pulse-Doppler and had a larger antenna.
 
Phantom tech said:
I was a radar technician stationed in Thailand during the Vietnam war. I was testing out operation of a system on the flight line, something I didn't have very many opportunities to do. Using the B sweep mode set for a hundred miles range I picked up a Target about 70 miles out which I can only assume from its size was a B52. I locked on and tracked him approximately 2 to 3 minutes before I was jammed by electronic countermeasures.
Click to expand...
Nice story. I was a F-4 radar tech in a USMC squadron in the late 70's in the US only. One evening on the flightline, checking some radar function without hydraulics, and with the antenna pinned to bore-site, I went to tx and picked up a target approx 45 miles out. For kicks, I tried and got a lock on it, and tracked it all the way until if flew overhead -- all with the antenna pinned to boresight. It was an airliner flying directly in our direction. Too funny.
 
overscan (PaulMM) said:
AWG-10 is a much more advanced radar using Pulse-Doppler and had a larger antenna.
Click to expand...
What i meant was the range of weights between 650-750lb given for the AWG-10, rather than a specific figure like for APQ-120 and indeed other radars be it russian, american, french etc.
 
lancer21 said:
What i meant was the range of weights between 650-750lb given for the AWG-10, rather than a specific figure like for APQ-120 and indeed other radars be it russian, american, french etc.
Click to expand...
Reading through the AWG10 thread, the system got updated with more and more digital parts in it, which I would suspect brought the weight down.
 
Not quite sure where i found this, but here is a compilation of F-4 radar detection ranges in kilometres (very useful to me as i can't think in nm), i think must be from a russian guy. I haven't yet sat down to compare these figures with the nm figures posted here previously.

USAF used F-4D and F-4E variants of Phantom.

F-4D had AN/APQ-109 Pulse-Doppler radar with instrumented range (maximal possible range of detection) of 110km. It provided for detection and illumination of aerial targets, air-to-ground ranging, ground beacon identification and display capabilities - radar display could show the picture from imaging guided munitions like AGM-62 Walleye. 110km being the maximal possible range, it allowed F-4D to detect fighter-sized targets at 40–50km and tracking at 20–30km.



F-4E had AN/APQ-120 Pulse-Doppler radar with instrumented range of 93km. It had less range since radar dish was decreased in size to allow onboard cannon to be mounted nearby. AN/APQ-120 was fully solid state and retained ground mapping capabilities from interim AN/APQ-117. Detection and tracking distance for fighter-sized targets decreased too, 35–40km and 15–25km accordingly.

USN and Marine Corps used different Phantom variants, F-4B and F-4J.

F-4B had AN/APQ-72 pulse-Doppler radar, predecessor of AN/APQ-109/120. Similar to AN/APQ-109 but without display function.

F-4J received AN/APG-59 pulse-Doppler radar, the best in Phantom lineage. Instrumented range of 150km; it retained all air-to-ground functions of previous models and received important look-down capabilty. Improved mapping mode. Detection of fighter-sized targets at 60–70km and tracking at 40–45km.



For MiG-21, we will look at MiG-21S and MiG-21bis.

MiG-21S received RP-22S “Sapphire-21” pulse-Doppler radar. Element base was mostly lamps. Instrumented range around 40km, allowing to detect fighter sized targets at 15–20km and track at 5–10km. This was the first MiG-21 radar able to provide illumination for SARH missiles. Mostly the same capabilities as AN/APQ-109 except for displaying: detection and tracking, plus rangefinder function for gun solution in computing sight.



MiG-21bis had RP-22SM “Sapphire-21M” pulse-Doppler radar. Element base still mostly lamps. Slightly improved RP-22S - better scanning angles, better resolution and resistance to false signals, range mostly the same.

Comparing the two radars directly… AN/APQ-120 family provides more capabilities for air-to-ground missions, allowing the use of imaging guided munitions, rangefinding and cartographer functions. RP-22 has only rangefinder and ability to guide beam riding Kh-66 missile.

In aerial roles, both radars had similar functionality - detection and tracking, no look-down, no tracking of multiple targets, no track-while-scan mode (both had boresight mode though). AN/APQ-120 family had massive advantage in range (two-three times) and had better scanning angles. RP-22 scanning angles were limited since radar dish couldn’t move too much inside the nose intake - AN/APQ-120 family had more wider array of movement.

AN/APG-59 outclassed Sapphire three-four times range wise and is the only one among compared here to have look-down capability.

The difference should not surprise you - Phantom and 21 met each other quite often, but these fighters were of different weight categories. Contemporary MiG-25P capabilities were more in line with Phantom.
 

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