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Dante80

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A Mk41 VLS also has 2 sections.

Part of the reason is the 2second interval between VLS launches.
My understanding was that the question had to do with splitting the arsenal between bow and amidships, not about the compartmentalization of the array/cluster itself. Could be wrong in this.
 

Tam

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Tam

Captain
Registered Member
One thing I am interested to know if PLAN hospital ships are capable of traveling up the Yangtze into Wuhan, to support the medical operations there. If not, can they be used to support medical operations on coastal cities?



thediplomat_2016-04-12_14-17-22.jpg
 

Tetrach

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Hey @Tam

Months ago you said that the angling of Type 382/Fregat M2 was for signal comparison.

One face is at 55 degrees and the other is at 45 degrees. The Russians have never fully explained the reason for that, but my guess is that the results between the two faces are compared to better precisely obtain both azimuth and elevation information on the target. If its really only about increasing update rate by going dual faces, the dual faces would be identical. The imposed differences between the two faces are deliberate for the purposes of signal comparison.
Yet here i found this :
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"Since the frequency-dependent beam swiveling also affects the horizontal antenna rows, the resulting antenna beam swivels from bottom right to top left:i.e. diagonally. In order to compensate for this, the entire antenna face was rotated until the beam swiveling appears vertical again."

I do not understand both suppositions anyway; I've tried to educate myself on the wonderfully complicates world of radar designs but no results. Can you please explain me?

I roughly understand what basic.radar says: the beam is going vertically so we need to angle the array for a fully straight scan. But why is it the only radar to do that, even tho phased rotating radars exist without this feature?
 

Tam

Captain
Registered Member
Hey @Tam

Months ago you said that the angling of Type 382/Fregat M2 was for signal comparison.



Yet here i found this :
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"Since the frequency-dependent beam swiveling also affects the horizontal antenna rows, the resulting antenna beam swivels from bottom right to top left:i.e. diagonally. In order to compensate for this, the entire antenna face was rotated until the beam swiveling appears vertical again."

I do not understand both suppositions anyway; I've tried to educate myself on the wonderfully complicates world of radar designs but no results. Can you please explain me?

I roughly understand what basic.radar says: the beam is going vertically so we need to angle the array for a fully straight scan. But why is it the only radar to do that, even tho phased rotating radars exist without this feature?
The language of the article isn't very clear. But to sum it all, this kind of array only scans up and down. The method it uses is frequency scanning. If you have a series of elements, A, B, C, D, E. If each element emits a slightly different frequency from each other, it will cause the beam to steer in one direction. All elements need to emit at the same frequency for the beam to go straight.


What causes the frequency to change from one radiator element to another is a slight delay getting the signal at the line feed.

The array is fed at the bottom and at the side, and the signal goes through all these loops you see at the side of the array, feeding each radiator element serially, not all at the same time.

st68u-ant (1).gif

This is why you see the array has this arrangement on the side.


11730557516_cb8550c33e_b.jpg

This is the American equivalent called SPS-48. This array is used with all US carriers, LPDs, and LHDs, so its a very important radar in the USN inventory.

vtygn2i0-900.jpg


SPS-48 might be a better example of the type because its a conventional textbook example.

What I'm not sure about Top Plate is that each radiator may also have a series of transmitting elements, and as the feed goes from left to right, there is a slight delay feeding each element along the length of the radiators which causes the beam to steer horizontally, while at the same time,feeding the radiators serially causes the beam to steer vertically. The result is a beam that steers across the face diagonally, and the array has to be aligned offset, so the beam ends up being steered vertically.

On top of that, the radar has another array on the back, on a slightly different angle, running on a higher frequency, so its dual backed, and dual frequency. The radar tutorial article makes it appear one band is in the L-band (D-band), while the other is in the S-band (E-band). The wiki article on the Type 382 describes the Chinese derivative having one array on the S-band and the other on the C-band. Most articles simply say the radar works in the S-band. I am assuming one side works on the longer range of the S-band and the other on the shorter range.

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I don't know why MR-710 Fregat "Top Plate" needs to work this way compared to other frequency scanning radars, and why its the only radar that works this way. The designers of the radar never really said their reasons. Every other frequency scanning planar array is set like you see with the SPS-48. The Type 381 radar, which is China's first radar of this type and used on the 051B, also has a vertical layout. The search radars used with SAM batteries also have the conventional layout. Adding to the questions is that the same company's other radars of this type don't feature the same arrangement.

Fregat MAE-4K-2.JPG36aac2fc9c8ab967889bdf6c27b28378.jpg
 

Tetrach

Junior Member
Registered Member
Hey, can someone quickly explain me the method to name ship classes ? with type 52D is named like this ?
 

Tam

Captain
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Hey, can someone quickly explain me the method to name ship classes ? with type 52D is named like this ?
The way the PLA code their ships is strange, just like the PLAAF code their serial numbers on the planes.

I am not sure how countries that use "Type" this and that, explain their numbers, like the Royal Navy with Type 42, 45, 26, 31 and so on.

With the PLAN, the Type numbers seems to indicate what type, mission, displacement, and engine propulsion type.

Type 00X--- Carrier
Type 01X --- Reserved
Type 02X --- FAC
Type 03X --- SSK
Type 04X --- Reserved, possibly SSK
Type 05X --- Surface warship
Type 06X --- Reserved, possibly surface warship
Type 07X --- Assault vessel, LPD, LHD
Type 08X --- Reserved, possibly assault vessel or transport
Type 8XX, 9XX --- Auxiliary
Type 09X --- Nuclear Submarine

Then it gets a bit complicated how ships are named within a segment.

Type 051 --- Luda
Type 051B --- Shares nothing with the Luda, only the principle of steam power.
Type 051C

Interestingly there is a bit of DNA shared among these ships, but otherwise, they differ greatly with each other. 052 and 051B are contemporaries, why the 052 instead of 051 suffix likely relates to the gas turbine used.
Type 052
Type 052B
Type 052C
Type 052D

Type 053X family are all these small, diesel powered frigates that goes back to a Soviet ancestor. Note how you go to a destroyer, and suddenly to a frigate.

Type 054X family are intermediate sized diesel powered frigates. Will a gas turbine powered intermediate sized frigate still get a 054X designation? Or will it be a new one? Some speculate it might be Type 057.

Type 055 --- Suddenly you jump to a large ship here.

Type 056 --- Then you jump back to a small corvette here. Corvette does not exist with the PLAN, this is a "light" frigate.

Note that if you go smaller, like a FAC, its not a 05X number. You have an entire series --- 02X --- that is only being used by one ship, the Type 022.

Is the Type sequence also due to the time the project development started? The subs seems to follow this sequence of development, but the Type 071 LPD vs. the Type 072 LST does not. Neither does the Type 052 vs Type 053 Jianghus. Also interesting is the Type 031 test sub vs. the Type 039 submarines, or for that matter, Type 055 vs 056.

This is a long way to say, there is no clear method, we just go what the rumors are sounding this ship will be numbered like.
 

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