CW vs. Pulse-doppler

[veit]

Just a general avionics question regarding russian vs. US BVR modes. I understand the EM theory behind both CW and pulse-doppler. It makes sense to me that that the US aircraft can alter pulse frequency in BVR mode from HI/low/ILV. However, from my understanding, all the Russian aircraft modeled only operate with CW radar, so how is it that they can alternate pulse frequency if they don't implement pulse doppler? Or do they implement pulse doppler in BVR mode?

 

I've also heard of something called CW pulse doppler but I'm not sure what that's supposed to mean exactly...

[Guest IguanaKing]

PRF is independent of whether your radar has doppler filtering ability or not. PRF is a transmitter characteristic, its just a variation to how many times per second the Magnetron "rings". :)

[tflash]

Are you sure those Russian radars are pure CW? In my view they are pulse-doppler radars. On a pure CW radar there is no such thing as PRF, since there is no pulse.

[Bimbac]

Hello everybody,

 

I think the truth is something in between. For example, the MiG-23M and its derivatives had some special radar system. As far as I know the radar wasn't a pure CW, not a pure pulse although it also wasn't Doppler.

 

This particular system was reported to be so effective, that notching won't work at all and you could track a target 90 degrees off your logitudial axis. So this system was reported to be more effective and more deadly than the radar system on MiG-29.

 

This knowledge comes from the real pilots that flown MiG-23s in Czech Air Force.

[Pilotasso]

Unfortunatly the Mig-23 was one of the fighters that had the worst combat record. To me its no coincidence that the Mig-21 is out living it by far. So there must have been some heavy downsides to that system.

[Guest IguanaKing]

Are you sure those Russian radars are pure CW? In my view they are pulse-doppler radars. On a pure CW radar there is no such thing as PRF, since there is no pulse.

 

I think you're right. I can't imagine something as powerful as a fighter radar being CW.

[Pilotasso]

CW were not vulnerable to beaming and notching but they were mostly useless looking down, so...

[veit]

Well perusing the Lock On manual, it states that while the Russian and American fighters have different radar systems, they both employ pulse doppler radar (both the N-019/01 and AN/APG-63 radars were pulse dopplers). That pretty much answers the question, but I have another question. I can understand how CW radar can't tell distance, but it seems that a pulse doppler radar should be able to tell distance simply by observing the time it takes for each pulse to return from a specific source (Of course the antenna would have to be directional to discriminate sources). However, I think only on the F-15 does this information show up (at least I think). Anyone know why?

[Guest IguanaKing]

Any type of radar can tell distance. RADAR=RAdio Detecting And Ranging. :smilewink: Are you maybe referring to closure rate or NCTR?

[GGTharos]

What do you mean 'only on the F-15 does this information show up'?

 

When you see your target on the Russian HUD, it is drawn at a given distance corresponding to what the radar sees, unless the target is jamming.

[veit]

Oops, you're right, I wasn't looking at the HDD, hehe

[nscode]

You didn't have to.... it's drawn on HUD too :)

[Bimbac]

Unfortunatly the Mig-23 was one of the fighters that had the worst combat record. To me its no coincidence that the Mig-21 is out living it by far. So there must have been some heavy downsides to that system.

 

Yes, you are right. But there are many things to consider:

 

1) MiG-23s sold to Middle East countries had a different set of avionics. For example, MiG-23S and MS sold to Syria and Lybia had avionics from MiG-21, including radar system. The pilots were also poorly trained and used obsolete tactics. They were no match to well-trained and battle-hardened Israeli veterans.

 

2) The radar system itself was quite sophisticated (in its timeline, of course) but also very complicated both to use and to maintain. The aircraft maintenance cost was just too high and that's the reason why many countries reverted back to MiG-21s.

 

3) MiG-23 was also the very first Russian fighter to implement the Radar/EOS combo.

 

According to my sources, the MiG-23ML/MLD should be more deadly opponent in a BVR fight than MiG-29, as I said before.

 

Regards.

[Святой]

According to my sources, the MiG-23ML/MLD should be more deadly opponent in a BVR fight than MiG-29, as I said before.

Looks like TRUE. It's confirmed by all of Mig-23Mxx pilot's opinions I heard on different russians aviation forums. Mainly the Sapphire-23's can perform single target tracking more stable than Mig-29's N-019, which usually lost it's target if it perform any maneuvers and change it's aspect. Reliability and perfection level of N-019 is considerably less than the Sapphire-23 has.

Germans using their MIG-29 only in joint with F-4 groups because without of F-4's radars fighter group will blind.

[Святой]

Сообщение от Pilotasso

Unfortunatly the Mig-23 was one of the fighters that had the worst combat record.

But MiG-23's kill ratio better than Mig-29's. There are 3 confirmed victory of soviet MiG-23 fighters over iranian helicopters, which were shut down on Afganistan and USSR teritory. May be Iraqi's MiG-23's shut down anything during Gulf War 1980-1987. MiG-29 everywhere was victim only.

[Pilotasso]

2) The radar system itself was quite sophisticated (in its timeline, of course) but also very complicated both to use and to maintain. The aircraft maintenance cost was just too high and that's the reason why many countries reverted back to MiG-21s.

 

Thats interesting, I never knew that.

 

According to my sources, the MiG-23ML/MLD should be more deadly opponent in a BVR fight than MiG-29, as I said before.

Regards.

 

Depends, a fighter combat potential is not only as good as its pilot training but also depends on the missile to get to target. The AA-7 Apex was even worse than the R-27 series in that regard and could even be outmanuevered by fighters.

 

The Mig-23 may have a good radar (comapretively of course) but the missiles werent too good. To make things worse, the main IR missiles the 23 saw most of its life time were AA-2 Atols and AA-8 Aphids. Both were rear aspect but the later required even more a favourable 6 o clock position because of its shorter range, and that required the Mig to do something it wasnt designed to do: To be a manueverable beast. Its was only matched with the F-4 phantom wich itself wasnt all that grand to outmaneuver the mig-21.

[GGTharos]

Sooo will these radar problems be modelled in LO? :)

 

 

And Pilotasso: Latest MiG-23 variants can carry, IIRC, R-27 and R-73.

[Pilotasso]

I said most of its life time. ;)

 

Their usefullness is less than good these days, and those missiles would be better off mounted on Mig-29's wich BTW were more unfortunate than the 23 only because of circunstances. Most of the 23's were destroyed well within visual range where a good piloted 29 would be better. But that was over 20 years ago, now things would be different with shots being taken further away.

[MiGMadness]

I said most of its life time. ;)

 

R-23T & R-24T was produced at the same time as their radar guided brothers.

 

[Pilotasso]

Thats the AA-7 Apex I talked about. And the belly missiles is the AA-8, what a horrible place to mount them. Seriously limiting.

[Святой]

Sooo will these radar problems be modelled in LO?

It's a joke?

[GGTharos]

Not really. I believe if an aircraft or weapon has certain problems in real life (that are not related to maintenance) then they should be modeled, so I would hope to see radar sets modeled accurately as well in this respect.

[Guest Hell Sqn Protos]

It's a joke?

 

S~!

 

Why? Is realistic radar modelling funny??

[Святой]

There are more important unmodelled aspects of radars and other avionics than devices''s troubles and problemms, but .... ED already spoke about this.

Information about russian avionic's problemms more accessible for us than same info about western devices. If troubles of devices of both sides will not be modelled it may destroy balance.

[GGTharos]

On one hand, I agree.

On the other, because the MiG-29 has effectively parity in radar capability and small missile superiority with R-77 in LO, things are not as they are in real life against F-15C or Su-27.

 

I believe that the simulation should aim to make people use realistic tactics, and because of how things are modeled now, realistic tactics cannot be used in many cases.

 

I hope in the future, as ED makes things more realistic, LO or its successor will require use of realistic tactics in BVR combat :)