PLAN Type 052C/052D Class Destroyers

Discussion in 'Navy' started by Jeff Head, Mar 14, 2014.

  1. DDr
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    DDr Just Hatched
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    If you say so, bucko :)

    Carry on with the rumor-mongering as usual.
     
  2. Max Demian
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    Max Demian Junior Member
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    I was reading "Type 346 inherits the design feature of the prototype of grouping four transceivers into a 100W peak power T/R module with its own power source." as if the 100W per module was for the production model.

    Alternative explanation might be that the "peak power' for AESA and PESA might not mean the same. It could be peak power at some nominal duty cycle which is not specified. If your read the article about the NIIB AESA: http://www.ausairpower.net/APA-2009-06.html you can see that in the low duty cycle regime the L-band power transistors can exceed 500W. Also here for Dutch L-band power transistors.

    I think the Japanese had AESA radars fielded back then. The US fielded the PAVE PAWS AESA radar in the early 80s: https://en.wikipedia.org/wiki/PAVE_PAWS . That behemoth had "only" a 320W peak power per T/R module for a total peak of 580kW per face. Its duty cycle was quite a bit higher than SPY-1, at 18%.

    Could also imply average, instead of peak power.
     
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  3. Tam
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    Tam Senior Member
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    For a specific reason, pulse doppler doesn't work well on PESAs.

    https://en.wikipedia.org/wiki/Pulse-Doppler_radar

    Antenna[edit]
    Pulse-Doppler radar is generally limited to mechanically aimed antennas and active phase array.

    Mechanical RF components, such as wave-guide, can produce Doppler modulation due to phase shift induced by vibration. This introduces a requirement to perform full spectrum operational tests using shake tables that can produce high power mechanical vibration across all anticipated audio frequencies.

    Doppler is incompatible with most electronically steered phase-array antenna. This is because the phase-shifter elements in the antenna are non-reciprocal and the phase shift must be adjusted before and after each transmit pulse. Spurious phase shift is produced by the sudden impulse of the phase shift, and settling during the receive period between transmit pulses places Doppler modulation onto stationary clutter. That receive modulation corrupts the measure of performance for sub-clutter visibility. Phase shifter settling time on the order of 50ns is required. Start of receiver sampling needs to be postponed at least 1 phase-shifter settling time-constant (or more) for each 20 dB of sub-clutter visibility.

    Most antenna phase shifters operating at PRF above 1 kHz introduce spurious phase shift unless special provisions are made, such as reducing phase shifter settling time to a few dozen nanoseconds.[13]


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

    Active phased array[edit]
    Active electronically-scanned arrays (AESA) elements incorporate transmit amplification with phase shift in each antenna element (or group of elements). Each element also includes receive pre-amplification. The phase shifter setting is the same for transmit and receive.[32]

    Active phased array do not require phase reset after the end of the transmit pulse, which is compatible with Doppler radar and pulse-Doppler radar.

    Passive phased array[edit]
    Passive phased arrays typically use large amplifiers that produce all of the microwave transmit signal for the antenna. Phase shifters typically consist of waveguide elements controlled by magnetic field, voltage gradient, or equivalent technology.[33][34]

    The phase shift process used with passive phased arrays typically puts the receive beam and transmit beam into diagonally opposite quadrants. The sign of the phase shift must be inverted after the transmit pulse is finished and before the receive period begins to place the receive beam into the same location as the transmit beam. That requires a phase impulse that degrades sub-clutter visibility performance on Doppler radar and Pulse-Doppler radar. As an example, Yttrium iron garnet phase shifters must be changed after transmit pulse quench and before receiver processing starts to align transmit and receive beams. That impulse introduces FM noise that degrades clutter performance.

    Passive phased array design is used in the AEGIS Combat System.[35] for direction-of-arrival estimation.
     
    #3043 Tam, Mar 4, 2019
    Last edited: Mar 4, 2019
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  4. Tam
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    Tam Senior Member
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    Posted by cirr at the PDF. This might be the 17th 052D.


    D17.jpg
     
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  5. DDr
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    DDr Just Hatched
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    [​IMG]

    :p

    So we've moved from "traditional sources are inadequate for the mighty PLA" to verbatim quoting Wikipedia articles. Progress! :)

    It again doesn't show any real comprehension of how the DB values that you mock are actually used in the sim, and therefore whether it makes sense to include them in non-air platforms or not, but it's a step up. Come on, you can do it ;)

    (The funniest thing is: There have long been people making PLA-related requests in the CMANO forums, and these are processed just like all others. So the whole "CMANO DB is outdated on Chinese systems" shtick around here and elsewhere is more accurately expressed as "we're not bothering to take the fragments of accurate facts flying around, put them together into a coherent picture, separate reality from wishful thinking and put forward a solid case". Ya know, like others do :))
     
  6. vincent
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    vincent Junior Member

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    Holier-than-thou BATMAN!!!
     
  7. Bltizo
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    Bltizo Lieutenant General

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    For the purposes of PLA watching, the "wishful thibking" you describe has been demonstrably ahead and superior to mainstream public outlets and sources.
    I don't think this is a matter of debate anymore. It has been repeatedly demonstrated year over year, project by project.

    For the purposes of trying to code in capabilities for something like CMANO, it becomes more difficult because exact specifications and comparative capabilities are often harder to substantiate, however I would wager that the estimates of experienced PLA watchers are likely closer to reality than others who rely on mainstream sources.


    My personal preference would be to simply not have PLA systems represented whose capabilities are under sufficient secrecy that sensible estimates cannot be made.

    Or conversely to allow the capabilities of all systems to have their specifications varied and redefined as part of the client without having a centralised database that only the devs can modify.
    The current system where the devs rely on "accurate facts" for PLA systems is obviously flawed because PLA watching does not have anywhere near that level of detail which observing other military forces are privileged with. In which case it would be better to not code in a system at all rather than code in a system with a capability whose simulated performance is dubious at best.
     
  8. Tam
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    Tam Senior Member
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    Do note that two of the CMANO entries are as equally dubious as the Type 346A.

    Why?

    They are of the SPY-1D and the SPY-6. Nothing to do with Chinese radars, these are US radars.

    US NAVAL radars who has no business with Look Down Shoot Down because that only works for AIRCRAFT RADARS. Unless for some reason you want to shoot a sub underneath your Burke with your Standards.

    Pulse Doppler doesn't work well with PESA such as SPY-1D, yet the entry mentions it. The two separate Wiki articles make it clear that there is an issue that makes Doppler ambigious using a PESA type radar. Never mind that for longer frequency search radar applications, the preferred method would be MTI or Moving Target Indicator as opposed to PD.
     
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  9. Max Demian
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    Max Demian Junior Member
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    Can someone walk me through again the forum lore about the Type346 ESA radar on the 052C?

    If I remember way back in the mid 2000s, the logical thinking was that the radar has to also perform the guidance role in absence of dedicated FCR radars. For that purpose, S-band would not be adequate. Knowing that the HT-233 for the land version of HQ-9 is C-band, and has a search functionality in addition to missile guidance, it was reasonable to assume the Type 346 would share many of its aspects.
    The other thinking was that the radar is search and track only and the missiles themselves are ARH, based on the FT-2000.

    It was only in 2016 when someone posted a novella on the wiki page for the Type 346 that the forum lore shifted to the idea of dual S-band/C-band.

    Can we entirely dismiss the possibility that the 23rd institute (or whoever designed the C-band APAR) won afterall?
     
  10. Bhurki
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    Bhurki Junior Member
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    Undergoing fitting?.. Because 17th has already been launched in late Feb..
     
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