F-4E vs Mig-29A Combat Tree sustem. 20NM Boresight lock in bad weather.

[ASW]

This is how the Combat Tree system is used. We see the transponder signal on the radar screen. The enemy is visible as a bar on the radar screen. The friend is visible as two bars. I get the enemy's altitude from the AWACS, turn on the Boresight mode, and the enemy is destroyed.)
The APX-81 picks up the IFF signals from the Russian SPO module installed on the migs, and then gives a call signal. The automatic return confirms whether the aircraft was friendly or hostile. From there, the APX-81 somehow transmits location data.

I love the Combat Tree.

null

Edited November 16 by ASW

[ASW]

I couldn't see the MiG at all because of the clouds, the sun, and the shadows. I flew in the wake of my AIM-7 and then fired a second missile. The first one was just to scare the MiG, but it still hit its target.

[Кош]

First, SPO has nothing to do with combat tree, RWR doesn't emit anything. 

Combat tree is a repeater of intercepted interrogator signals. It then listens to transponders.

In DCS only transponder that is vulnerable to Combat Tree IRL is on MiG-19. Everything else has later encrypted models APX-81 can't deal with.

[Dragon1-1]

I think he meant SRO (IFF system), not SPO (RWR). Currently, Combat Tree works on all Soviet IFF systems, I think it can be set to "realistic mode" (actually vulnerable transponders only) in mission.

[ASW]

5 часов назад, Кош сказал:

First, SPO has nothing to do with combat tree, RWR doesn't emit anything. 

Combat tree is a repeater of intercepted interrogator signals. It then listens to transponders.

In DCS only transponder that is vulnerable to Combat Tree IRL is on MiG-19. Everything else has later encrypted models APX-81 can't deal with.

 

38 минут назад, Dragon1-1 сказал:

I think he meant SRO (IFF system), not SPO (RWR). Currently, Combat Tree works on all Soviet IFF systems, I think it can be set to "realistic mode" (actually vulnerable transponders only) in mission.

1. I made a mistake in one word "system", even in the name of the topic, because I didn't use the translator yesterday.(SPO-SRO)

2. The F-4E has three options for using the Combat tree system. All, historical and none.

3. I suggested doing the same with the SPO-15 Береза. At the user's or server's choice.

 

Edited November 17 by ASW

[ASW]

5 часов назад, Кош сказал:

First, SPO has nothing to do with combat tree, RWR doesn't emit anything. 

Combat tree is a repeater of intercepted interrogator signals. It then listens to transponders.

In DCS only transponder that is vulnerable to Combat Tree IRL is on MiG-19. Everything else has later encrypted models APX-81 can't deal with.

Т.к система секретная, то что стало доступным для общественности может являться не совсем правдой или вообще враньем. Вполне возможно, что в 90х были разработаны и другие подобные системы, но об этом никогда не скажут. Говорят, после угона Миг-25 в Японию переделывали именно системы свой-чужой.

Because the system is secret, what has become publicly available may not be entirely true or even a lie. It is possible that other similar systems were developed in the 90s, but this will never be mentioned. They say that after the hijacking of the Mig-25 in Japan, it was the friend-foe systems that were redone.

[Zabuzard]

7 hours ago, Dragon1-1 said:

Currently, Combat Tree works on all Soviet IFF systems

Thats not correct, please see the manual, thanks:

https://f4.manuals.heatblur.se/dcs/mission_editor.html#combat-tree-spoofable

[Кош]

7 часов назад, ASW сказал:

Т.к система секретная, то что стало доступным для общественности может являться не совсем правдой или вообще враньем. Вполне возможно, что в 90х были разработаны и другие подобные системы, но об этом никогда не скажут. Говорят, после угона Миг-25 в Японию переделывали именно системы свой-чужой.

Because the system is secret, what has become publicly available may not be entirely true or even a lie. It is possible that other similar systems were developed in the 90s, but this will never be mentioned. They say that after the hijacking of the Mig-25 in Japan, it was the friend-foe systems that were redone.

We're talking exactly Combat Tree. It worked with SRO-1 and SRO-2 but not SRO-2M and furter systems.

[Кош]

4 часа назад, Zabuzard сказал:

Thats not correct, please see the manual, thanks:

https://f4.manuals.heatblur.se/dcs/mission_editor.html#combat-tree-spoofable

There should be only MiG-15 and 19 in that list. Everything else has SRO-2M or newer. Unfortunately there are no older 21's in DCS.

Edited November 17 by Кош

[Zabuzard]

There should be only MiG-15 and 19 in that list. Everything else has SRO-2M or newer. Unfortunately there are no older 21's in DCS.

Yes and no.

You are misunderstanding the "Historical" setting. It is for people making a historical accurate mission, including the timeframe.
Any mission maker who places a Mig-21 unit in a historical accurate sortie for a F-4E will want the Mig-21 to not be a patched bis-variant.
So this is a compromise due to us not having all variants of all aircraft selectable.

Also, this is for the mission maker to decide. Do not forget that there are also the two other options None and All.

Historically, pretty much any enemy the modelled F-4E had to face was spoofable. Up to roughly 1980.

Cheers

[Кош]

10 минут назад, Zabuzard сказал:

Yes and no.

You are misunderstanding the "Historical" setting. It is for people making a historical accurate mission, including the timeframe.
Any mission maker who places a Mig-21 unit in a historical accurate sortie for a F-4E will want the Mig-21 to not be a patched bis-variant.
So this is a compromise due to us not having all variants of all aircraft selectable.

Also, this is for the mission maker to decide. Do not forget that there are also the two other options None and All.

Historically, pretty much any enemy the modelled F-4E had to face was spoofable. Up to roughly 1980.

Cheers

bis was not "patched". It started production years after combat tree was discovered and had SRO-2M from get go. For realistic historical context you need F13 and PF.

Edited November 17 by Кош

[Zabuzard]

bis was not "patched". It started production years after combat tree was discovered and had SRO-2M from get go. For realistic historical context you need F13 and PF.

Thats what I am saying though.
A F-4E that faced a Mig-21 in a sortie during 1970-1980 could see it with Combat Tree.

Mission Makers need to make compromises in DCS and the Mission Editor options we offer need to be compatible with their flows and processes.

If you want to make a mission where Mig-21 isnt detected by Combat Tree then simply select NONE in the mission editor. Which btw is also the default option.

[Кош]

7 минут назад, Zabuzard сказал:

Thats what I am saying though.
A F-4E that faced a Mig-21 in a sortie during 1970-1980 could see it with Combat Tree.

Mission Makers need to make compromises in DCS and the Mission Editor options we offer need to be compatible with their flows and processes.

If you want to make a mission where Mig-21 isnt detected by Combat Tree then simply select NONE in the mission editor. Which btw is also the default option.
 

yes and bis cosplay 4 generations of mig 21 in DCS 

[Zabuzard]

Right.

Thing is, the "Historical" setting is there because we thought it might render useful for some mission designers. I am pretty sure though that most missions will either have selected NONE or ALL.

Either your mission plays during 1970-1980 and isnt a fictional scenario, then Combat Tree essentially saw everything. Or it doesnt play in that timeframe (or is perhaps fictional), then Combat-Tree doesnt see anything. Beyond that, some mission designers might or might not want to give the F-4E an "authentic advantage". Anyways, up to the mission authors to decide :)

[Dragon1-1]

It's unlikely there was a Combat Tree 2, because most likely, the problem that allowed Russian IFFs to be easily tricked into broadcasting the aircraft's position was fixed. Western IFF actually had a similar problem, Mode 1, 2 and 3 respond to any interrogation attempt, and the signal can be figured out by simply observing an interrogation with an antenna tuned to the appropriate frequency. Far from being outside the Soviets EW capabilities, there was never a Combat Tree equivalent for fighters, but EW aircraft and ground stations could possibly do this, and then vector in the MiGs. This is why Mode 4 exists, with its rolling encryption scheme that prevents the enemy from just copying the interrogation signal to locate the aircraft. I don't know how exactly the newer Soviet IFFs handled this, but it was probably a similar thing.

[Кош]

6 часов назад, ASW сказал:

It would be great if HB made a version of the Mig-21 at the F-4E level. As for Western technologies vs Soviet technologies, I'm not sure there wasn't a Combat Tree-2 for example. After all, if it had been made, it would not have been written about in the newspapers or BBC news.

As for the difference in modern technology, today I was sent a video comparing the latest Russian robot and a Chinese robot. The presentation of the Russian robot took place last week.

I think Zabuzard will like this video, but KOSH may not like it. But this is not a fake or an AI-generated video. This video gives me another plus in the piggy bank that the DCS engineers did the SPO-15 correctly and realistically.

(unfortunately, I can't afford to watch the Mig-29A yet because my pension in Russia is 17,300 rubles ($213) per month.)

Comparing Russia to USSR is like comparing finger and REDACTED

 

Edited November 18 by Кош

[ASW]

5 часов назад, Dragon1-1 сказал:

It's unlikely there was a Combat Tree 2, because most likely, the problem that allowed Russian IFFs to be easily tricked into broadcasting the aircraft's position was fixed. Western IFF actually had a similar problem, Mode 1, 2 and 3 respond to any interrogation attempt, and the signal can be figured out by simply observing an interrogation with an antenna tuned to the appropriate frequency. Far from being outside the Soviets EW capabilities, there was never a Combat Tree equivalent for fighters, but EW aircraft and ground stations could possibly do this, and then vector in the MiGs. This is why Mode 4 exists, with its rolling encryption scheme that prevents the enemy from just copying the interrogation signal to locate the aircraft. I don't know how exactly the newer Soviet IFFs handled this, but it was probably a similar thing.

Very interesting. I didn't know that mode 4 was encrypted and used for exactly this purpose.

[Dragon1-1]

DCS really needs to actually model the peculiarities of IFF. For instance, Mode 4 has two codes, A and B, which are usually changed at midnight, with today's B becoming tomorrow's A. If you fly at midnight and forget to flip the A/B switch on your IFF panel, nobody will respond to your Mode 4 interrogations unless they also launched the previous day and forgot about the switch. You won't respond to the new code, either. Mode 1, back when it was in use, could identify not only friendlies, but everyone had a specific mission code, so you could find, say, bombers you needed to escort by interrogating their code in Mode 1. Mode 2 could be used to find specific aircraft in the same way. Of course, you were supposed to turn those modes off at fence in, along with Mode 3.

[ASW]

When you understand what it's about, it's incredibly interesting. Many people don't understand what this is about. I flew an interesting company on an F-4 and when I landed, there was such an inscription on the screen.)

[ASW]

давайте закроем эту тему. вроссии за песни на улице в тюрьму сажают, а за секрет СПО-15 РАССТРЕЛЯЮТ . а потом как минимум обоссут.)

(если меня забанит некто Бигнев, то я не буду покупать ихний Ф-18 и т

[ASW]

осталось 3 дня проката, есть подарок 10 000, вот не знаю, что лучше поддержать парней из дкс...

[Dragon1-1]

On 11/18/2025 at 3:11 PM, ASW said:

When you understand what it's about, it's incredibly interesting. Many people don't understand what this is about. I flew an interesting company on an F-4 and when I landed, there was such an inscription on the screen.)

The problem is, DCS doesn't teach you about IFF and the modes are for most part nonfunctional, despite obvious utility of modes 1 and 2 in certain scenarios. The only thing we do have is a magic mode 4 transponder. This is probably a holdover from the times of Flanker and Ka-50, since Soviet IFFs generally only have very rudimentary controls in the cockpit. The switchology actually exists in most appropriate modules, but it doesn't do anything.