Type 055 DDG Large Destroyer Thread


Richard Santos

Senior Member
Registered Member
Can you clarify what you mean by a reduced quality firing solution and what causes it?

If your aim is off, then no matter what the ROF is, you won’t hit the target.

If the solution quality is known to be less than desired, a higher rate of fire would allow the fire control to more effectively compensate by moving the aim point about the approximate location of the target while spraying bullets.
 

nlalyst

Junior Member
Registered Member
I don't know why its narrow if it can be considered narrow on the 052D. Perhaps it doesn't need to interrogate as many aircraft as the Shandong, and there are power, weight, electrical infrastructure, EM interference constraints that you do not need the device to be more than the intended mission.

On the 055, those things look too big just for HQ-9 communication. My speculation is that the book ends of the system are for HQ-9 communication, with the bridge between the bookends being the IFF interrogator. There are actually eight bars around the top of the superstructure, the four above the radars are the thick ones, and you got another four in the between. The between ones however are too thin when compared to the Type 346A IFF bars, and furthermore they feature a back end structure whereas the other IFF bars doesn't. The 4th bar is visible from the back of the superstructure. You have the thin set about 12, 3, 6, and 9 o'clock of the ship, and the big thick ones about 45 degrees of each diagonal from the ship's axis. Could this be another radar set or another IFF set?
The ones facing 12,3,6,9 look in width comparable to the panels on the Type 052D. I would wager that these are the IFF. If they worked on the Type 052D, they should work on the Type 055.

An argument I've heard from Henri K in favor of the larger panels being IFF is the reportedly significantly higher performance of the Type 346B radar. On the face of it, that seems sound. However, I see two problems with that.

1. IFF typically operate at much longer wavelengths: the USN's IFF operates at 1030-1090 MHz. That's 6-8 times lower frequency compared to C-band used to communicate with the HQ-9 missiles. I will assume that PLAN's IFF similarly operates at comparable UHF frequencies (do you have more precise data?): 1GHz UFF vs 7 GHz comm link.

Even in typical clear weather, we are looking at 2-5 times more specific signal attenuation at 7GHz versus 1 GHz (db/km) (exact numbers depend on water vapor content in the air). If we add moderate rain into the picture, the ratio can widen to over 100 times the difference, with fog and clouds to 1000 and in heavy rain to over 10,000 times (for the duration of the atmospheric disturbance).
Take a look at these graphs:
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Let's assume that HQ-9Bs have a range of about 250km. Let's also assume both antenna have equal output power and gain. In perfect weather conditions, the Type 346B should have an instrumented range of at least 250*3.5=875km to justify using a more powerful antenna for IFF. However, against a target flying at 10km its theoretical radar horizon is roughly 415km. Even against a target flying at 15km, it's still just 500km.

Of course, the calculus changes if the C-band array is allowed to have more radiating power and gain, which might be the case if they are both AESAs.

2. If those are the IFF, where are the C-band missile comm antennas? Still embedded in the Type 346B radar?

6d0e4d765d5a4027a4f41a872c890292_th.jpg
 
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Tam

Brigadier
Registered Member
The ones facing 12,3,6,9 look in width comparable to the panels on the Type 052D. I would wager that these are the IFF. If they worked on the Type 052D, they should work on the Type 055.

An argument I've heard from Henri K in favor of the larger panels being IFF is the reportedly significantly higher performance of the Type 346B radar. On the face of it, that seems sound. However, I see two problems with that.

1. IFF typically operate at much longer wavelengths: the USN's IFF operates at 1030-1090 MHz. That's 6-8 times lower frequency compared to C-band used to communicate with the HQ-9 missiles. I will assume that PLAN's IFF similarly operates at comparable UHF frequencies (do you have more precise data?): 1GHz UFF vs 7 GHz comm link.

Even in typical clear weather, we are looking at 2-5 times more specific signal attenuation at 7GHz versus 1 GHz (db/km) (exact numbers depend on water vapor content in the air). If we add moderate rain into the picture, the ratio can widen to over 100 times the difference, with fog and clouds to 1000 and in heavy rain to over 10,000 times (for the duration of the atmospheric disturbance).
Take a look at these graphs:
Please, Log in or Register to view URLs content!


Let's assume that HQ-9Bs have a range of about 250km. In perfect weather conditions, the Type 346B should have an instrumented range of at least 250*3.5=875km to justify using a larger antenna for IFF. However, against a target flying at 10km its theoretical radar horizon is roughly 415km. Even against a target flying at 15km, it's still just 500km.

2. If those are the IFF, where are the C-band missile comm antennas? Still embedded in the Type 346B radar?

Let's take this shot.

51186629868_e5ade7f8b1_k.jpg


The design of the larger bars look like this.

[ ]======[ ]

There are two book ends on the sides, or its thicker on the sides.

iff4.png

My hunch is that the book ends, the ones I marked in gold, are the HQ-9 datalinks.

iff5.png

The green part is the IFF itself. The length of the actual IFF itself is shorter than the entire bar because the ends of the bar are the C-band communication antennas. They look like its a single long array but that's only the cover.

I will point out that this bar has segmented design, and if you have seen IFF before, the antenna is divided into segments. The IFF on the 052D is also divided into a similar number of segments.

iff1.png

You can see that the book ends is a different device from the bar and have their own air circulation at the back.

As for the bars at the 12, 3, 6 and 9 o'clock locations, there is something on back of them (red ?) that I don't see on the 052D IFF. This is a new device or a new design, or to the very least its not the same. You can check the 052D here.

46381367515_4c56d97748_o.jpg

Blue ? is another puzzle as they are set on all four corners of the bridge wing. These are set on 45 degree positions from the ship. These are also my datalink candidates.
 
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nlalyst

Junior Member
Registered Member
...
@Deino
Why is the discussion about Type 055 sensors off topic in the Type 055 thread?
 
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Deino

Lieutenant General
Staff member
Super Moderator
Registered Member
...
@Deino
Why is the discussion about Type 055 sensors off topic in the Type 055 thread?

Since you are constantly not only discussing the 055's sensors but the whole story of SAM systems, and so on ... we have dedicated topics, @siegecrossbow already deleted a few post, me too, we gave two kind reminders and now it is enough.
 

nlalyst

Junior Member
Registered Member
Since you are constantly not only discussing the 055's sensors but the whole story of SAM systems, and so on ... we have dedicated topics, @siegecrossbow already deleted a few post, me too, we gave two kind reminders and now it is enough.
Well I am not happy with this kind of moderation. I had previously asked the moderators to move the discussion that steered off into missile guidance to the dedicated thread. What did the moderator do? He deleted the entire discussion. And now you delete it again.

EDIT: I see that just now some posts were finally moved to the missile guidance thread. Thank you!
 

Deino

Lieutenant General
Staff member
Super Moderator
Registered Member
Well I am not happy with this kind of moderation. I had previously asked the moderators to move the discussion that steered off into missile guidance to the dedicated thread. What did the moderator do? He deleted the entire discussion. And now you delete it again.


No, I'm not a moderator to clean up the mess! Stick to the topic, listen what the moderators say and if there are a few, then please inform the moderators but stop with this endless discussion until it is enough.

I cannot and in fact I'm not in the mood - to read pages of stuff to sort out what can remain and what should be moved.

Honestly, You are mature enough at least to stop after a warning!
 

Shimakazerun

New Member
Registered Member
The two points that you make are shockingly surprising to me. Do you mind elaborate on how you get this?
  1. I am old and have many relatives in the military some have served as early as the 1960s. I have never heard such things especially that PLA was officially named "National Defense Force" for whatever length of time.
  2. "Chinese Navy" is a English phrase, not a official title in English. It is like calling Xi Jingping Chinese president, but his official title remains Chairman of PRC in English. Just because somebody choose that English phrase in the English newspaper does not mean anything.
have seen a central document of the Cultral Revolution from 1960s signed by Zhou Enlai which had a title 《关于派国防军维护铁路交通的命令》"the order to send the national defense force to protect the railway".
 

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