SPO15 feedback

[TotenDead]

5 часов назад, JediMaster сказал:

 

There's a reason they were either retired or upgraded and not still in use in 1980's setup in 2025, just like the F-4Es.

Or the F-16A...

But no, there're some unmodified 9.12s still in service here and there

[суховей]

9 часов назад, Harlikwin сказал:

From what I can determine. The blanker board basically is just programmed to turn off the input to the SPO in 3 microsecond intervals (the length of the TX of the N019).

Here is my thoughts about kassette 51 and shutdowning SPO . It is wrote in russian from russian thread. 

The textbook on SPO-15 and technical characteristics of RLPK-29 are used as a basis. 

 

The point of that post is that cassette 51 should recognizes HPRF pulses in normal mode.

Here is raw translating:

I decided to write my thoughts about cassette 51 and disabling the system from HPRF pulses. I'm not an expert, so please don't kick me)

 

1. Cassette 51, among other things, is responsible for selecting the received pulses by DURATION (not by frequency)

Спойлер

2. The system classifies pulses into 4 types (strobe) based on their duration

Спойлер

3. The MiG-29 radar has a pulse duration of 1.25-1.5 microseconds at HPRF. 

Спойлер

4. The system must recognize and classify the HPRF pulse as a t3. Or t2 strobe.

Спойлер

Attention, question. Why should cassette 51 disconnect the system from the effects of HPRF pulses if it recognizes HPRF normally?

Edited October 11 by суховей

[okopanja]

49 minutes ago, суховей said:

Here is my thoughts about kassette 51 and shutdowning SPO . It is wrote in russian from russian thread. 

What are your thoughts on 12, 13, 14?

[суховей]

3 часа назад, okopanja сказал:

What are your thoughts on 12, 13, 14?

There are no cassette 12, 13, 14 according to the textbook. If you mean that. 

EDIT. 

In my post, I wanted to say that the logical scheme of the cassete 51 do not provide for disabling the system from HPRF signals. 

Edited October 11 by суховей

[okopanja]

2 hours ago, суховей said:

There are no cassette 12, 13, 14 according to the textbook. If you mean that. 

In my post, I wanted to say that the logical schemes of the SPO-15 do not provide for disabling the system.

I meant the pages from the SPO-15 document. 

[суховей]

1 час назад, okopanja сказал:

I meant the pages from the SPO-15 document. 

There are prohibition signals. 

The prohibition signals are also used to lock( blank) the station's receiver channels when the aircraft's radar is transmitting. The prohibition signals are synchronized with the locking (blanking) signals of the onboard radar.

Спойлер

With a well-synchronized radar and SPO-15, everything should work.

It's not the HPRF signals that can shutdown the SPO, but rather poor synchronization with the radar.

I edited my previous post.  Change "the logical schemes of the SPO-15 do not provide for disabling the system" to "the logical scheme of the cassete 51 do not provide for disabling the system from HPRF signals". 

https://forum.dcs.world/topic/379025-spo15-feedback/page/14/#findComment-5705172

Edited October 11 by суховей

[AeriaGloria]

4 hours ago, суховей said:

Here is my thoughts about kassette 51 and shutdowning SPO . It is wrote in russian from russian thread. 

The textbook on SPO-15 and technical characteristics of RLPK-29 are used as a basis. 

 

The point of that post is that cassette 51 should recognizes HPRF pulses in normal mode.

Here is raw translating:

I decided to write my thoughts about cassette 51 and disabling the system from HPRF pulses. I'm not an expert, so please don't kick me)

 

1. Cassette 51, among other things, is responsible for selecting the received pulses by DURATION (not by frequency)

  Reveal hidden contents

2. The system classifies pulses into 4 types (strobe) based on their duration

  Reveal hidden contents

3. The MiG-29 radar has a pulse duration of 1.25-1.5 microseconds at HPRF. 

  Reveal hidden contents

4. The system must recognize and classify the HPRF pulse as a t3. Or t2 strobe.

  Reveal hidden contents

Attention, question. Why should cassette 51 disconnect the system from the effects of HPRF pulses if it recognizes HPRF normally?

Great job! I would love to have someone from ED look at this post! Very convincing!!!!!

[суховей]

28 минут назад, AeriaGloria сказал:

Great job! I would love to have someone from ED look at this post! Very convincing!!!!!

I wanted to show the cause-and-effect relationships of the SPO shutdown. They are not the same as described by ED. The reason for the shutdown may not be the HPRF signal itself, but the poor synchronization with the radar.

With a well-synchronized radar and SPO-15, everything should work.

Edited October 11 by суховей

[Кош]

As far as description of SPO goes, blanking signal from radar is connected parallel to internal band(U1 U2) selection logic ANDs. Blanking from radar overrides internal blanking oscillation on band selection. Chips that, by description, accept blanking commands, can work at frequencies up to 1.5 or up to 3 MHz depending on model. Even worst case scenario is 10 times faster than HPRF. So, if any design flaw is taking place it should be somewhere in radar block N001-35-11. Otherwise it's either faulty connections or board components.

[суховей]

7 часов назад, Кош сказал:

So, if any design flaw is taking place it should be somewhere in radar block N001-35-11. Otherwise it's either faulty connections or board components.

However, in real life, there is no SPO shutdown on serviceable aircraft.

This is confirmed by the words of real pilots and flight manuals. Only incorrect indications may occur, which is normal. 

Edited October 12 by суховей

[суховей]

Maybe ED just doesn't know how to implement incorrect indications? Which happen sometimes and are a vague concept to implement, and it was easier for ED to disable the SPO?

 

[Harlikwin]

On 10/11/2025 at 4:52 AM, суховей said:

I wanted to show the cause-and-effect relationships of the SPO shutdown. They are not the same as described by ED. The reason for the shutdown may not be the HPRF signal itself, but the poor synchronization with the radar.

With a well-synchronized radar and SPO-15, everything should work.

Yeah this is my interpretation of the documents we have. Moreover the "flase" signals displayed are what actually happens when the SPO starts to go out of synch. 

As for how ED implements this correctly, IDK. Maybe just a special option to fly with the broken SPO. And then have a "perfect SPO" as the default option. Ideally maybe they have errors that start to appear (desynch) after some random amount of flying time. What we lack is info on rapidly the spo would desynch, could be minutes, or tens of hours. And then to reset it, well that takes a radar technician to reset it with his gear. 

[addman]

On 10/12/2025 at 11:27 PM, Harlikwin said:

Yeah this is my interpretation of the documents we have. Moreover the "flase" signals displayed are what actually happens when the SPO starts to go out of synch. 

As for how ED implements this correctly, IDK. Maybe just a special option to fly with the broken SPO. And then have a "perfect SPO" as the default option. Ideally maybe they have errors that start to appear (desynch) after some random amount of flying time. What we lack is info on rapidly the spo would desynch, could be minutes, or tens of hours. And then to reset it, well that takes a radar technician to reset it with his gear. 

Sounds like a never ending rabbit hole IMO. But yeah, having a toggle between "perfect condition SPO" and "worn out/de-synched 1990's Yugoslav SPO" would probably satisfy most people.

[суховей]

В 14.10.2025 в 15:49, addman сказал:

Sounds like a never ending rabbit hole IMO. But yeah, having a toggle between "perfect condition SPO" and "worn out/de-synched 1990's Yugoslav SPO" would probably satisfy most people.

By the way, the average uptime of the SPO-15 is 300 hours. After that, it needs to be serviced.

[Кош]

21 час назад, суховей сказал:

By the way, the average uptime of the SPO-15 is 300 hours. After that, it needs to be serviced.

Or 33 calendar days, whatever comes first. Thankfully there are devices for automatic diagnostics.

Edited October 16 by Кош

[-SunAx-]

As I understand it, this module simulates a specific Polish aircraft with specific maintenance deficiencies. In addition to fully digitizing the visual representation, it would be necessary to also conduct a diagnostic check for defects. It might suddenly turn out that due to metal fatigue, the wings of this aircraft will fall off under an acceleration of over 5g. And the simulator has negligently failed to take this into account.

[AeriaGloria]

I did some signal strength tests with the intent of finding changeover from X category to F for F-14, F-15, F-18, etc. 

F-14 is complicated, so that’s another day. 
 

First off, CW detection is naturally not as good as non CW as it requires 2 bar signal strength to pass threshold rather then 1. And at these ranges where these planes are mistaken as Hawk (X category), it can only tell that it’s CW. 
 

F-15 is first detected around 80 km. F-18 around 75 km. From there both slowly increase to 5 signal strength X category until 25 km, where they transition to 1 bar X and F category, and then both exponentially increase to near full signal strength at merge (F-18 was a few bars short of full at merge, F-15 was full). 
 

Couldn’t find distance of 50/90 light turning on for F-18, but for F-15 was 10 km and 13 for F-14. 
 

F-4E was special, not being high PRF it can be detected further, up to 200 km. Will pass middle of strength gauge between 45-25 km. F-14 went from max detection at 150 km to middle signal strength at 45 km, and exponentially increased to about 10-12 bars around 10-15 km. 

Of course. If emitter is from 80-120 degrees off nose, the signal strength will be much lower the closer to 90 degrees it is.
 

And at long range detection, two front azimuth lights will light up at shorter range then one. While signal strength is added for both so that stays the same, it simply has a slightly higher threshold to fully light up the two sectors compared to one as it is hitting them slightly off boresight. So for example, only left or right “10” light will show at first (at very long range, you may see bearing before signal strength or category appear) even if directly at 12 o’clock. Then as it can categorize it (even falsely, such as putting 4th gen’s at “X” at medium to long range) you should be able to get the more precise azimuth measurement of being able to have an adjacent pair of two antenna sectors lighting up. 

Edited Tuesday at 01:44 AM by AeriaGloria

[sylkhan]

On 10/5/2025 at 9:13 PM, AeriaGloria said:

SPO will still show radars it does not recognize just not categorize them and thus give them very low priority. Then there are many radars it might confuse as enemy 

Doesn't seems to work that way, i did some test with su-27 and spo-15 behave the same way, friend or foe.

Edited Monday at 09:38 PM by sylkhan

[AeriaGloria]

7 minutes ago, sylkhan said:

Doesn't seems to work that way, i did some test with su-27 and spo-15 behave the same way, friend or foe.

I wouldn’t be surprised if it’s confusing it for some western 4th HPRF/MPRF signal. Which would of course reduce any utility against 4th gen’s. Not sure what it couldn’t confuse at this point

[AeriaGloria]

More testing. 
 

F-14 shows as flashing X like other 4th gen at long range, but then shows P + X within 60 km. Perhaps it is AI turning on CWI early 

When it launches sparrow, switches to P & C category interestingly 

F-4 made much more sense. C normally then P & C for launch. 
 

F-16, perhaps it is the radar mode AI is using, but was identified as flashing X + F much further then F-15/18, around 40 km, and total max detection of 50 km as flashing X. 
 

But within 30 km, flashing X disappears and is 100% identified in F category. 
 

Then I tested Fox 3. 
 

Everyone was scared becuase Q&A said average 2-4 sec warning, but I was pleased with the results 

First detected as 2 bar X category at 8 km, 5 bars at 5 km, and under 3 km rapidly goes from 6-10 bars. 
 

Just wonder how MPRF modes of F-15/18 affect things and why F-14 shows C category and no F. 

 

Edited Tuesday at 04:17 AM by AeriaGloria

[Dudikoff]

6 hours ago, AeriaGloria said:

Just wonder how MPRF modes of F-15/18 affect things and why F-14 shows C category and no F. 

Perhaps because AWG-9 uses Pulse (LPRF) at closer ranges? It has no MPRF modes, IIRC.

Edited Tuesday at 11:11 AM by Dudikoff

[AeriaGloria]

7 hours ago, Dudikoff said:

Perhaps because AWG-9 uses Pulse (LPRF) at closer ranges? It has no MPRF modes, IIRC.

I also wonder if it’s becuase P category was also often used for “Naval” radars as they were often CWI. 

[Muchocracker]

Wouldnt be surprised if the AI do things differently. Probably would be better to test using a player controlled aircraft. 

I can't think of any reason why would switch to pulse search mode just because it's at closer ranges. AWG wouldn't do that

Edited Tuesday at 04:57 PM by Muchocracker

[Dudikoff]

16 hours ago, AeriaGloria said:

I also wonder if it’s becuase P category was also often used for “Naval” radars as they were often CWI. 

And the C category is probably because it uses LPRF Pulse mode to keep target in track as the HPRF PD mode might lose track when the target turns to the side or to run away.

More modern PD radars would use MPRF here.

Edited 16 hours ago by Dudikoff

[AeriaGloria]

8 hours ago, Dudikoff said:

And the C category is probably because it uses LPRF Pulse mode to keep target in track as the HPRF PD mode might lose track when the target turns to the side or to run away.

More modern PD radars would use MPRF here.

Makes sense! Thanks!!!!

Do you know if this is for all locks or just during STT missile guidance? 

Edited 8 hours ago by AeriaGloria