He also pointed out that the IAF has taken steps to ensure its radio communication is safe from jamming by the enemy. "They won’t be able to hear our communication. Fighter pilots are getting secure radio communication," he replied when asked whether Pakistan would be able to jam the communication with IAF pilots as they did in case of Wing Commander Abhinandan Varthaman during February 27, 2019, dogfight.
Even if we haven't talked about the same; they knew it and would have gone to secure Comm in future.
Comms in Military domain are always secure - that's the first criteria for selecting equipment. Link-16 is one such example for communication/Data transfer in the air. On ground, Military Radios, even Police/ambulance/Fire-B Radios are secure. The frequencies used by Military and Civil forces are known all over the world, and even if Channels are known, and somebody tunes into that channel, nothing will be heard. Anything send over the air (HF/UHF/VHF and other bands etc) is now out of transmitter's control and anybody can intercept that using a receiver - unless its encrypted. Militaries all around the world pay millions of $$$ for getting encryption and security features installed in their comm equipment. In normal lives as ordinary citizens, Security features like secure communication in apps as well as incognito windows in internet explorers are also available for everyone.
So firstly, its hard to imagine that Indian Military is operating Aircraft without secure/encrypted radios.
Secondly, if PAF has mentioned that Indian comm convo has been intercepted after eaves dropped, then this brings in the factor of ability to break through encrypted security features of Radios installed in IAF aircrafts, but that is what Jamming is supposed to do. What else would one expect when AWACS, EW aircraft and F-16 are flying in the air ?
Which radios are used by IAF aircrafts ? which Data Links ? Russian or Israeli ? Actually, Russian Vs Israeli communication/Data Link systems opens a whole new debate.
Where was IAF AWACS? Where were IAF EW aicrafts?
Rafale uses Link-16, the security protocols for Link-16 are confidential and not publicly provided. It also has DRFM, which can store incoming signals and then processes them to be re-transmitted. F-16 has these features already. Why has Rafale become so important for IAF this year- one wonders. Although, yes Communication radios can be different but Data Link is necessary.
Thirdly, the Feb 2019 incident shows that Pakistan Military's SIGINT Capability had been in use before this incident occurred. I am not much aware of PAF exercises, inside Pakistan or around the globe, members like windjammer keep a tab on that. Somehow it seems that PAF had been practicing EW capabilities in its exercises. The ability with which PAF conducted this operation using EW for interception and jamming shows that this scenario has been practiced thoroughly in exercises.
I know that PA's eaves dropping capability has been exponentially increased after Ops in FATA region. Such capabilities were put into practice as early as 2004-5, when communication was being intercepted from enemy in Wana, Waziristsan and from Afghan side. Sat Phones of Thuraya were in use of enemy. Communication issues n caves forced the enemy to leave the cover and expose themselves on peaks of hills and mountains. These same eaves dropping techniques were then put into practice on LOC. Weaknesses in Radio Comm showed PA itself how much secure comm is necessary and Harris Radios were inducted. There were other different kinds of Radios too that were inducted.
Fourthly, Jamming produces noise signals, which are basically unwanted signals, so enemy gets to know that communication is getting jammed. Eaves dropping and SIGINT are different. There might not be any interception in Eaves dropping so enemy wouldn't know but there can be interception in SIGINT, since security features need to be cracked, hacked, decrypted or by-passed, therefore any such action can cause detection. SIGINT is itself a broad term and has many types.
If the event maintained itself at eaves dropping stage, then PAF could have kept it secret, if it went further ahead where interference was necessary, then IAF would have known. Knowledge of being jammed is obvious.