[JohnBooty]

    To combat this it is suspected that Americans use a
    technique that involves 'ghosting' commercial airliner
    traffic to mask the signatures of their jets against 
    the lower frequency, longer range, radar. 

That sounds fascinating. A quick Googling bore no fruit for me. Can you elaborate, or point me in the direction of more information?

[moftz]

They can change their radar signature since the true signature isn't much of anything. They can mimic the signature of other planes and even move the signature making it seem like the spoofed aircraft is closer or further away than it really is. If you move the spoofed signature much closer to a radar installation, they might fire off a missile from another location that was previously hidden. Make the spoofed signature large enough and they may not see the anti-radiation missile heading towards them. There are also expendable versions of this tech that can be dropped from a plane like chaff, further increasing the distance between the spoofed signature and the true one.

https://en.wikipedia.org/wiki/Digital_radio_frequency_memory

https://www.militaryaerospace.com/computers/article/16726118...

https://www.c4isrnet.com/electronic-warfare/2019/05/15/can-n...

[acomjean]

Its a cat and mouse game between airplanes and radars.

Radars are usually arrays of small radars now that can move the beam without even moving, chirp the frequecy and do all sorts of weird things. I wrote OS software to help control them years ago, which was interesting.

http://www.radartutorial.eu/02.basics/Stepped%20Chirp%20Rada...

its an interesting exercise in signal processing. there are lots of books on the subject: And hey! my radar made a cover.

https://www.amazon.com/s?k=radar&i=stripbooks&ref=nb_sb_noss

[moftz]

I think radar is absolutely fascinating. I work in a different RF field but sometimes I wish I got drawn into that instead.

[JohnBooty]

Fascinating. Thanks!