PLA AEW&C, SIGINT, EW and MPA thread

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enroger

Senior Member
Registered Member
tphuang said:
right, that's what I was thinking. They just got so much better with processing and algo to get usable data for better resolution of the targets.

Also, for dual band solutions, maybe that's only something they figured out more recently and how to have receivers efficiently filter out signals that are not in the band it's sending. IDK, that seems possible.

I'm not sure how they implement this. Do you 1 set of antenna that have separate power amplifiers for 2 different bands and 1 layer that does filters and decide what to filter out and then process that.

Or do you have separate antennas? Not sure if that's how it works. Just thinking this through in my mind.

I also do think that based on what I've seen previously, you do need larger antenna for VHF band, so that could be the reason you can only do it on these back to back antenna.
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I think at the very least there'd have to be separate antennas given that UHF and L-band has such huge difference in wavelength, someone more familiar with rf can chime in.

I speculated on the possibility of dual band system a couple pages back and a member gave some very good reasons why this is difficult, primarily with how to fit antennas of such a large scale difference packing close together and not interfering with each other. If KJ-3000 is really a dual band system like this then one wonders just what kind of black magic those CATIC guys are brewing....
 
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AndrewS

Brigadier
Registered Member
MeiouHades said:
By PPP at least, yes. But even still, that's way too much money especially on R&D which seems to be showing no signs of slowing down in China
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Consider how US military spending is like 3.5% of GDP.

In comparison, the last (older) Chinese figures are about half that level (~1.8%?)

Consider how everyone in the world sees the US as being "overly" aggressive towards China, as per public comments by Ray Dalio and the late Henry Kissinger.

So if China wanted to match US spending levels, China should really be doubling it's military spending.

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Given that Chinese military spending is overwhelmingly spent inside China using Chinese resources, PPP is the better measure as it looks at actual output of goods and services in an economy.

The exchange rate just reflects the supply/demand dynamic for the the US Dollar and Chinese Renminbi. And remember the Chinese government explicitly manages the currency.

What matters is what your USD or RMB can actually buy.
 
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AndrewS

Brigadier
Registered Member
enroger said:
I think at the very least there'd have to be separate antennas given that UHF and L-band has such huge difference in wavelength, someone more familiar with rf can chime in.

I speculated on the possibility of dual band system a couple pages back and a member gave some very good reasons why this is difficult, primarily with how to fit antennas of such a large scale difference packing close together and not interfering with each other. If KJ-3000 is really a dual band system like this then one wonders just what kind of black magic those CATIC guys are brewing....
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If the radar is dual-faced, could it be a rotating radar? We see the E-3 and E-2 do this.

Then you could have one face as UHF and the other L-Band.

That would solve a lot of the interference issues and still allow a maximum size radar array.

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So let's say the radar rotates at 30 rpm and the faces have a 120° field of view.

With enough signal processing, my guess is that you can have enough coverage for volume search and also enough time to focus on specific target tracks as well
 
E

enroger

Senior Member
Registered Member
AndrewS said:
If the radar is dual-faced, could it be a rotating radar? We see the E-3 and E-2 do this.

Then you could have one face as UHF and the other L-Band.

That would solve a lot of the interference issues and still allow a maximum size radar array.

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So let's say the radar rotates at 30 rpm and the faces have a 120° field of view.

With enough signal processing, my guess is that you can have enough coverage for volume search and also enough time to focus on specific target tracks as well
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It is possible but I think it would be a little unwieldy. Say your UHF detected some stealth target and if you need to obtain high resolution tracking you have to swing the whole array arround to train your L-band on it..... especially when AWACS needs to handle large number of targets at the same time.

Edit: On second thought, yeah if the array rotates at 30rpm then it is possible to use UHF and L-band together as the time interval is short enough. I totally forgot how mechanically scanned radar works hahaha
 
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A

AndrewS

Brigadier
Registered Member
enroger said:
It is possible but I think it would be a little unwieldy. Say your UHF detected some stealth target and if you need to obtain high resolution tracking you have to swing the whole array arround to train your L-band on it..... especially when AWACS needs to handle large number of targets at the same time.

Edit: On second thought, yeah if the array rotates at 30rpm then it is possible to use UHF and L-band together as the time interval is short enough. I totally forgot how mechanically scanned radar works hahaha
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You could also stop the rotation and have a face stare in the one direction, like the E-2
 
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