i koliko god je spoznaja jednostavnosti MiG-25 bila šokantna spoznaja za Amerikance, pomenuti događaj je bio neuporedivo šokantniji za Ruse, koji su zbog toga odustali od izgradnje 2 nosača aviona, i odvojena sredstva preusmerili u zamenu sistema za idetifikaciju u svim borbenim aviona VVS SSSR-a, što ih je koštalo 2 milijarde tadašnjih rubalja ...
Stvar je vec bila provaljena ranije za vreme Vijetnamskog rata:
According to now declassified U.S. sources, Combat Tree was an IFF interrogator that could interrogate MiG IFF transponders. It was first
installed on a small number (8?) of F-4Ds in late'71 or so, which were operated by the 432nd TRW (The serial numbers are given in Anthony
Thornborough's "The Phantom Story"). I've checked his list against the Red Baron reports, which identify whether and which a/c in a flight are Combat Tree equipped and which contacts were due to Combat Tree, and cross-checked those incidents with listings of those kills which include the a/c serial numbers. They match).
Because of the small numbers available, typically only the flight lead (01) and (when available) the element lead (03) would be in 'Tree'-equipped birds. 02 and 04 were often in F-4Es, to provide some gun capability without forcing the F-4Ds to carry gun pods. Because of the loss of several of these a/c, some more (about 20?) were modified in mid '72 (available July, I think). Later, when the Rivet Haste slatted F-4Es showed up in theater to re-equip the 555th, they were apparently all equipped with it.
Combat Tree had several positive effects. First, it allowed U.S. fighters to acquire MiGs at much greater ranges than they could from a primary return (i.e. a skin paint). Second, it allowed them to make contact looking down in many cases. This meant that free-roving MiGCAPs were much more effective than they had been; previously, the NVn would just vector there MiGs around U.S. MiGCAPs by keeping them low until they'd gotten out of our a/c's radar arcs. It also meant that we were allowed to take more BVR shots with the AIM-7 than we'd previously been able to. An example the initial engagement of Oyster flight on 10 May 1972. Lodge in 01 and Ritchie in 03 were both flying Tree-equipped a/c, and Lodge's and Markle's kills were both fired BVR because of a Combat Tree ident.
It wasn't perfect. There were limits as to how close a Tree contact could be to other a/c, before a BVR shot was allowed. In at least one case, an a/c ID'ed as a MiG by Tree was visually ID'ed by TISEO gear as an F-4, fortunately before a shot was taken. In addition, the NVN was montitoring our radio coms. When our pilots started to report contacts on MiGs at previously unheard of ranges, they started to get suspicious, and curtailed their use of transponders, only turning them on at turn points or the like instead of using them continuously as they had previously.
For the best, most accessible discussion of Combat Tree, QRC-248 (a similar interrogator installed on board the EC-121s from 1967; Michel, quoting from a declassified document, says theat QRC-248 would tyypically allow an EC-121 Connie which might have trouble detecting a MiG at 100nm at medium altitude, to detect them at 175nm at low altitude) and the rest of the Vietnam air campaign, you should find a copy of "Clashes," by Marshall Michel (sp?). This is based on declassified U.S. documents now available from the Historical Research Center in the archives at Maxwell AFB, checked by Michel's own experience. The HRC has a website listing some of what's available, although it tends to be a bit out of date, and last time I checked, none of it was on-line; yopu have to order the stuff by mail, or go there. I have a friend who works there, and he's made copies for me.
1.) How it (APX-80) functions?
Each aircraft carries an IFF-transponder. Basically (very basically), IFF-transponders can either be set "on" all the time, and continuously send signals which identify them on the radars, or be set "passive", and send responses to interrogation signals which ask them for their identity.
APX-80 could do both. I.e. it could read the signals of active SRO-2 IFF-transponders, or trigger them to respond. The result is always the same: once the IFF-transponder answers (regardless if on "on" or "off") it reveals the position of the aircraft by which it is carried.
2.) When it entered service, what air forces uses them?
The widespread use of the APX-80 started, however, only with the arrival of F-4E Mod.556 in SEA, that was from autumn 1972.
It is almost 100% certain that the E-2C used at least a similar (but certainly highly advanced) system in 1982, as well as that the F-15As have had it too. To which degree was it used during the fighting in Lebanon is unknown, but it is obvious that for some reasons the Israeli Eagle drivers always knew very well what are they engaging - and that already in 1979.
Certain is also, that such IFF-interrogators can track even aircraft which are yet to start; i.e. it can track any fighter which activates its SRO-2 while still on the ground, regardless if this is set on active or passive.
But, it is also sure that in 1982 the IDF/AF has operated UAVs over several Syrian air bases.
4.) the effects of the Combat Tree can at best be described as follows:
imagine flying a bomb-laden F-4 deep over the enemy-held territory; from the previous recce, you roughly know the positions of SAM- and radar-stations, as well as that there are several airfields operating MiGs nearby.
But, your GCI coverage cannot provide you with proper radar picture of the situation in the air in real time, especially not when it comes to low-flying enemy interceptors.
If you engage your radar, the likelyhood is that you will detect something ahead of you, but not very far, and there is no guarantee for this, especially not at ranges possible with the Combat Tree. And, it is even more likely that the enemy completely unknown to you will detect your radar emission - even if flying aside or behind you - with the help of his RWR and ESM systems.
It might actually be better for you not to engage your radar at all...but then you could stumble right into a well set-up trap.
Still with me?
OK. Now, imagine you having the capability to detect ALL enemy interceptors which operate in the direction where your radar antenna is pointed, without you activating the radar, but only pressing "the button"?
Woooaaaa - all the MiGs in front of you can suddenly be seen on your radar display.
You don't have a radar contact with them, but you can read who they are and see what they are doing (direction, speed, flight level etc.).
With the Combat Tree in your Phantom you don't need to activate your radar. You just point the radar antenna into direction you want to scan, and activate the APX-80. It will immediately show you (it uses the radar display) all the "MiGs" with active IFF-transponders out to 50-60kms in the air and on the ground in front of you. I.e. it will show you also those MiGs which your radar couldn't detect except they are flying at ranges closer than 15-20kms. All of this regardless of the level at which the MiGs operate (the system detects even those SRO-2s on the planes which are on the ground, but are eventually testing them, or rolling to take off etc.).
And then, by pushing "a button", you can also trigger IFF-transponders of enemy fighters which are not set on active.
With other words: you know what is going on ahead of you, where are potentional enemies, and what are they doing, but they don't.
5.) The Soviets couldn't catch onto this, as they were only informed about what the Vietnamese knew and wanted them to know. Sometimes mid through 1972 the Vietnamese got a clue that the Americans are tracking their planes with the help of something. So, they started to left their IFF-transponders on passive.
Now, the problem was also, that due to poor training of USAF crews, crapy communications equipment, poor weapons and tactics, the APX-80 couldn't make that much difference in air battles any way. So, it is highly likely that the Vietnamese - and therefore the Soviets - haven't realized the full importance of the system (the Soviets certainly haven't until well into the IPGW).
Then the Parol was introduced which changed the IFF-code each day. From what I know this far, apparently, this haven't helped either.
6.) There was actually no "range" of the Combat Tree, but usually it had no problems detecting MiGs out to 60km or so.
7.) The reporting about the position of enemy aircraft was actually more precise than done by the radar, because the radar has to be properly calibrated in order to deliver exact data.