Primarily because the Mig 29UPG and the Su 30MKI are not plug and play. Russia will have to convert them to plug and play first
I think you are confusing the concept of plug and play.
Plug and Play means you upload the driver software so the computer will recognise the hardware you are about to plug in to the system. Its features. Its capabilities. What information and power and data it needs from the computer (aircraft) and what information and data it generates and transmits back to the computer/aircraft.
If you are plug and play adding an AESA radar it means that you can just upload the driver, take off the existing radar and put your new radar on and it will work seamlessly.
If the MiG-29UPG and Su-30MKI are not plug and play... which we assume they are not, then you have to install some new hardware interface equipment to convert the data and signals from the new radar in a way that the aircraft thinks it is the old radar... but more powerful and longer ranged...
The thing is that even with plug and play an AESA radar is going to need a shed load more power and rather more efficient cooling systems too, and likely the bandwidth of data coming from the radar will be dramatically increased because of the larger volume of airspace it can cover.
But that is OK... if they integrated French and Israeli avionics to the aircraft there should not be any problems integrating Indian AESA radars... India developed the AESA and the Russians designed and built the planes so together both parts should be known inside out.
Pro west mafia could not sell the F 18 or the F 16. British plane was there in the form of Typhoon. It didn't qualify because of the lack of credible ground attack weapons.
The F-18 and F-16 are older than the MiG-29, and the Typhoon is only partly British... meaning components from countries that could block India from getting it...
As I said the whole programme was made up to reduce the asking price for the Rafale and it really didn't work.
And India remains by far the largest purchaser of Russian cruise missiles and air to air missiles. I'm not even including JV projects like Brahmos. India purchased US$ 2 billion worth of missiles from Russia in 2019 itself.
I honestly think India should focus more on an IADS and a joint venture for long range AAMs with Russia using scramjet motors. They are already looking at hypersonic Brahmos II which means scramjet motors anyway...
Who else internationally would work with India on scramjet motors? Who else even could?
Yes, but they are not AESA radars.
But they are. They are electronically scanned because the components can't physically move and each element scans a volume of space individually.
Think of it as an IR detector for a security system... most have one big IR element looking for moving heat sources... they don't care where the burglar is... they just want to know something is moving there... it would be no good for an APS because the APS system needs to know where the threat is and what direction it is coming from so it can intercept it. Imagine an IR detector with 1,000 elements each covering a sector of the room... the elements that detect the heat source can be used to determine precisely in that room where the threat happens to be. With an APS sensor it is active radar... it sends out a weak radar signal and can detect the reflections from within 100m... so the fixed element that detect the incoming target can determine the angle of the incoming threat and the radio signal return gives range and the dopplar effect on the signal gives speed... that is an AESA radar except it doesn't scan as such... it radiates all the time...
You don't have to convert every single MBT. In a tank battalion if you incorporate aircraft type AESA radar into just 1/4th of the total number of tanks that should be enough.
But why? It would be incredibly expensive but totally pointless... why are MBTs not fitted with aircraft radar now?
A MBT doesn't care about a plane flying 100km away... and most helos will fly too low to be detected reliably more than 5-6km away... it is like suggesting putting 1m thick armour on aircraft... stop any modern AAM or SAM from shooting it down and air defence guns would be useless too...
Then these tanks and possibly even a few BMPT that have AESA radars can carry out the surveillance part and share the composite picture with the other tanks in the battalion.
Picture of what?
Radar at ground level is terrible for picking up ground targets... most radars on ground vehicles are for detecting incoming artillery or enemy aircraft like on SPAAGs and SAMs.
For self defence the existing types are relatively cheap and simple and do what is needed to get the job done.
As an example the AESA radar in development for the MiG35 will have worse detection capability (just because it is smaller and less powerful (there is no space for a bigger one and also because the engine cannot provide more energy.....)).
Jet engines are often fitted with equipment to take power from the engine... jet engines have shafts on which the blades or disks are mounted... connecting those to electric motors effectively becomes a generator... the amount of power you can generate is determined by that generator and it is pretty clear the old generators were not designed for modern AESA radars and a full Avionics suite, but it is not impossible to create a new more powerful generator... or one for each engine.
AESA and PESA radars have very small sidelobes which makes jamming difficult.
AESA is more protected against jamming than pesa or mecanical radars because it can work on different frequencies at the same time. That's a fact.
PESA radars can operate in different frequencies within its operational bandwidth... and with electronic scanning can simultaneously scan down at ground targets in frequencies suitable for detecting and tracking ground targets while at the same time scan level and upwards in frequencies suitable for tracking air targets, or checking weather conditions and air moisture content....
An AESA radar has thousands of individual radar emitters that can modulate different frequencies and wave forms, and each emitter has noise filters so the information an AESA radar generates is already clean before it gets to the computers for processing and display... but having all those electronics means it also gets very hot very quickly so most IR seeking missiles that are tail chasers will be able to hit you nose on if you are using your radar.
If the enemy jammers can jamm your radar, you will lose big. Egyptian sa-6 were very good but became pretty useless once israeli found out what frequency they work on and made effective jammers.
Jammers are not always 100% effective... you know the frequency your radar operates at so you know the jamming frequency... having the ability to launch your missiles to home on a jamming signal is an obvious solution... once the jammers are destroyed... continue as usual.
What the Russians did was give it an optical backup channel to allow the battery to engage the enemy jammers.
The SA-6 also had one radar vehicle for each battery so when the radar vehicle was hit with a Shrike or HARM then F16s with dumb bombs could come in and destroy the now defenceless launchers.
SA-11 has guidance radars on each vehicle and optical backup to remedy that.
Russian AD relies a lot of ground based radar so they better be sure that Nato jammers can't jamm them totally. That's why you invest in new type of radars, datalinks, C2...
HATO doesn't have that many jamming platforms... most of which will be targeted by long range SAM very early on and taken out. Russia mixes a range of sources of target information within it IADS, and most radar are mobile or part of a protected SAM battery.
Jamming works both ways too of course.
For now Irbis is enough but if they find out it can be jammed by nato jammers they will switch very fast for a Byelka aesa or a new type of photonic radar which will also face new type of jammers.
New radars are more expensive, but would be justified if it was found current radars couldn't get the job done. Clearly they think they have time to make their other options better before putting them in service.
If all the armies go for photonic radars and jammers then a mecanical radar from the 70s will be very good because they will be focused on the photonic spectre of detection and it would very expebsive to switch for the radar spectre of signal...
You are assuming there is a way to jam a photonic radar. I suspect they will have trouble jamming it if they can't make their own yet...