Why wasn't the RADAR ever updated?

[PhantomHans]

So, I just have to ask, why wasn't the radar ever updated by most end users?

If I understand correctly, the F-4J and S got a pulse doppler radar.  But the F-4B,C,D,E,F,G, and N, other than those few later updated with modern radar by foreign users, did not get any updates.

 

As a side note, I understand the B,C,D, and N had a different radar than the APQ-120 but other than perhaps longer range due to the bigger dish I understand it to be quite similar?

I have no idea what the British F-4K/M had.

Seems kinda odd to me though as the radar is the one part of the jet that, at times, really seems to be lacking and hasn't been improved by the time of our E model.

[Ivandrov]

I'll talk mostly within the scope of the F-4E. But, usually the primary reason is money.

 

To be clear. The APQ-120 was actually upgraded, up to a v9, I believe.

But, given a certain budget, you can spend that money upgrading old airframes to fit the new radars (It's not just a matter of swapping dishes, often the radar is designed to fit the airframe not only in terms of size but things like power draw, and the weapons control systems) or you can just shove the new tech into a new airframe.

 

Of course, you have to realize that these are old airframes that might be reaching retirement anyway, with increasing maintenance costs.

 

The ones who continued to update the old airframes are usually the ones that can't really confidently meet the upfront cost of new ones. So, you're only left with the option of upgrade.

Edited September 15 by Ivandrov

[PhantomHans]

I figured a large part of it had to be cost.  Thing is, with the F-4 still being a major component of western air forces until 1990 (or even beyond) it seems like an APQ-120 replacement to give modern pulse doppler capabilities, even if at the cost of reduced range or horizontal scan volume for example, would have been a huge hit.

[Ivandrov]

4 hours ago, PhantomHans said:

I figured a large part of it had to be cost.  Thing is, with the F-4 still being a major component of western air forces until 1990 (or even beyond) it seems like an APQ-120 replacement to give modern pulse doppler capabilities, even if at the cost of reduced range or horizontal scan volume for example, would have been a huge hit.

Huge hit to money spent elsewhere, probably. Especially if we're talking post cold-war where the mindset became reducing the sizes and budgeting to military. There's certainly a priority list when it comes to this stuff and trying to convince people to upgrade old airframes when their first thought in their heads is, "Man, this thing is old, gotta find a replacement." Is extremely difficult.

[Cytarabine]

Several users who held onto their F-4’s into the 90’s and early 2000’s did modernise the radar with a new set, however by then in US service the Phantom was on the way out.

I guess it would be cool to have one of those variants, though to be honest we would end up destroying some of the charm of the current module with how challenging the radar is compared to more modern jets. 

[PhantomHans]

4 hours ago, Ivandrov said:

Especially if we're talking post cold-war

Ahhh see I was thinking during the cold war.  Like a late 1970s or early 1980s update just to get pulse doppler retrofitted.  Even if the set couldn't do TWS, had a shorter range, or smaller scan volume, pulse doppler seems like it would be so much more capable particularly in the low level ground attack role the F-4 found itself in.  Make it more able to defend itself.

By 1991 it doesn't make sense to me to upgrade it unless you just can't afford anything else.

But yes I guess money isn't unlimited.

[SuperKermit]

vor 6 Stunden schrieb PhantomHans:

Ahhh see I was thinking during the cold war.  Like a late 1970s or early 1980s update just to get pulse doppler retrofitted. 

Keep in mind that the F-15A started being implemented already in 1976 taking over the A2A role of the F-4 in US service. So why spend money on something you don’t need?

Edited September 17 by SuperKermit

[Kalasnkova74]

16 hours ago, Cytarabine said:

Several users who held onto their F-4’s into the 90’s and early 2000’s did modernise the radar with a new set, however by then in US service the Phantom was on the way out.

I guess it would be cool to have one of those variants, though to be honest we would end up destroying some of the charm of the current module with how challenging the radar is compared to more modern jets. 

Thing is, those modernized F-4s are really unique animals to the versions in game. It wasn’t just the radar sets, but the aircraft mission computers, weapon sets, and various avionics which were changed. On some modernized F-4s , enough wiring was consolidated to reduce the aircraft’s weight by thousands of pounds. 
 

There’s the APG-66 in the Hellenic , German ICE and Japanese F-4s, then the ELTA GMTI radar in the Kurnass 2000 (no Sparrow capability however), plus the AIM-120 integration for the Hellenic and German F-4s. Developing one of these would be a dedicated module in and of itself. 

[PhantomHans]

On 9/17/2025 at 10:32 AM, Kalasnkova74 said:

Developing one of these would be a dedicated module in and of itself. 

That's assuming you can even GET the documentation.  However I would be all in favor of getting an APG-66 F-4, I have to think that an F-4F module featuring the classic West German cold war birds (a little bit unique to the standard F-4E) and the later ICE update would be a great combination package for the new cold war map.  The F-4F's are even weirder in that, as far as I am aware, at some point they got AIM-7 Sparrow capability added, but never actually GOT the AIM-7 Sparrow since the West Germans never bought any (and neither did the united post cold war Germany either), at least according to the old Joe Baugher website.

 

What I was originally getting at was wondering why there wasn't a low cost radar upgrade from the late 70s or early 80s.  Basically a cheap, simple, light pulse doppler radar, trading off scan range and volume where required for a much clearer picture.  With how many F-4s held on until 1990 in US service, plus all the NATO and allies, I feel like it's something that might have sold if the cost was kept in check.  But if that wasn't something that could be done cheaply enough, obviously not going to be much of an interest to the USAF with their fancy new F-15.

[303_Kermit]

On 9/14/2025 at 11:49 PM, PhantomHans said:

So, I just have to ask, why wasn't the radar ever updated by most end users?

If I understand correctly, the F-4J and S got a pulse doppler radar.  But the F-4B,C,D,E,F,G, and N, other than those few later updated with modern radar by foreign users, did not get any updates.

 

As a side note, I understand the B,C,D, and N had a different radar than the APQ-120 but other than perhaps longer range due to the bigger dish I understand it to be quite similar?

I have no idea what the British F-4K/M had.

Seems kinda odd to me though as the radar is the one part of the jet that, at times, really seems to be lacking and hasn't been improved by the time of our E model.

The true reason is simple. M61A1 Vulcan Cannon. Either that or Pulse doppler filter module. Navy chose bigger antenna of the radar and look down shoot down capabilities, since they were interested more in A2A performance of F4. Airforces wanted something else, and they have an ammo box instead of Doppler module. That is one of the reasons, why whole front end of F-4 of Navy is different.

Edited Saturday at 01:59 PM by 303_Kermit

[jojo]

On 9/17/2025 at 7:32 PM, Kalasnkova74 said:

Thing is, those modernized F-4s are really unique animals to the versions in game. It wasn’t just the radar sets, but the aircraft mission computers, weapon sets, and various avionics which were changed. On some modernized F-4s , enough wiring was consolidated to reduce the aircraft’s weight by thousands of pounds. 
 

There’s the APG-66 in the Hellenic , German ICE and Japanese F-4s, then the ELTA GMTI radar in the Kurnass 2000 (no Sparrow capability however), plus the AIM-120 integration for the Hellenic and German F-4s. Developing one of these would be a dedicated module in and of itself. 

AFAIK, F-4F ICE got the APG-65 

[Volator]

5 hours ago, jojo said:

AFAIK, F-4F ICE got the APG-65 

Correct.

[Muchocracker]

On 9/14/2025 at 5:49 PM, PhantomHans said:

So, I just have to ask, why wasn't the radar ever updated by most end users?

If I understand correctly, the F-4J and S got a pulse doppler radar.  But the F-4B,C,D,E,F,G, and N, other than those few later updated with modern radar by foreign users, did not get any updates.

 

As a side note, I understand the B,C,D, and N had a different radar than the APQ-120 but other than perhaps longer range due to the bigger dish I understand it to be quite similar?

I have no idea what the British F-4K/M had.

Seems kinda odd to me though as the radar is the one part of the jet that, at times, really seems to be lacking and hasn't been improved by the time of our E model.

They tried to with the CORDS upgrade but it had huge performance and reliability issues with the vacuum tubes based memory storage. Trying to keep the total package weight down on the nose of radar + the gun was likely just not possible or too cost prohibitive for the late 60's. By the 80's its an old airframe, and cost is even more prohibitive.

[bfr]

On 9/14/2025 at 10:49 PM, PhantomHans said:

I have no idea what the British F-4K/M had.

The UK models were basically modified F-4Js and I think they finished life with what were basically AN/APG-60 sets with some tweaks.

[PhantomHans]

18 hours ago, Muchocracker said:

They tried to with the CORDS upgrade but it had huge performance and reliability issues with the vacuum tubes based memory storage. Trying to keep the total package weight down on the nose of radar + the gun was likely just not possible or too cost prohibitive for the late 60's. By the 80's its an old airframe, and cost is even more prohibitive.

I had to research it, but that seems like the type of upgrade I was talking about.  It makes me wonder why they didn't try to reintroduce it in the late 70s, especially if it could allow the existing APQ120 to be retained.

 

For the record I'm not suggesting that this would have kept the F-4E relevant as a fighter but rather that it would give it more "teeth" when pressed into a fighter role or when forced to defend itself on an A-G mission.  More situational awareness of potential threats, etc.

[DD_Fenrir]

4 hours ago, PhantomHans said:

I had to research it, but that seems like the type of upgrade I was talking about.  It makes me wonder why they didn't try to reintroduce it in the late 70s, especially if it could allow the existing APQ120 to be retained.

 

For the record I'm not suggesting that this would have kept the F-4E relevant as a fighter but rather that it would give it more "teeth" when pressed into a fighter role or when forced to defend itself on an A-G mission.  More situational awareness of potential threats, etc.

The mid to late ‘70s was not a strong period for the US economy; given the F-15 is being developed for the air to air role and the F-16 is coming on board specifically to be a more cost effective fighter and ground attacker and there are limited $ available, investment in the F-4 was likely not a priority; those bucks were better spent on the new toys.

[LG_Barons]

Can't some skilled modders or coders get an "ICE" upgrade to an F version? Is it possible to obtain somekind of  APG-6X? from the F-15C (APG 63), for example, and AMRAAM? 
The cockpit layout and the majority of the switches would remain largely unchanged. Therefore, there are not many graphic changes, such as those seen in the cockpit of a Greek F-4 Peace Icarus.

Details like the unusable 7th fuel cell or not implementing the Peace Rhine system are negligible, I guess.
I think there is no need for a complete new model, just an "Avionics update."".

[Temetre]

vor 23 Stunden schrieb PhantomHans:

I had to research it, but that seems like the type of upgrade I was talking about.  It makes me wonder why they didn't try to reintroduce it in the late 70s, especially if it could allow the existing APQ120 to be retained.

 

For the record I'm not suggesting that this would have kept the F-4E relevant as a fighter but rather that it would give it more "teeth" when pressed into a fighter role or when forced to defend itself on an A-G mission.  More situational awareness of potential threats, etc.

Its probably worth considering that the APQ-120 in 1980 was also just, under any circumstances, hopelessly outdated compared to F-14/15/16. The more advanced multirole concept, like defending yourself in A2G missions without dropping bombs was only really experimented with the F-18. And, as others said, the F-Tens were massive money sinks with lots of incredible advanced features, but also many problems that required fixing. The engines were a mess till the mid 80s after all!

Even Germany, who got F4s mainly as a stop gap measure, only upgraded their Phantoms so much because the Eurofighter program had massive delays. Greece and Turkey kept their F4s mainly in active reserve because of Turkey and Greece.

The USAF F-4s did get some upgrades, like the DMAS with its digital INS/nav/computer system. But that was specifically a light, low cost upgrade, and reflected its kater role as a strike aircraft with basic self defense capabilties.