Mig-21bis NEEDS a lower BR

Took my Finnish Bis for a spin, and:


Looks like it can detect RADAR locks just fine to me.

What’s more, the SPO-10 can detect H, I and J RADAR bands, and that includes every single F-4 Phantom’s RADAR in the game. Even the Kurnass 2000 only has a J band RADAR. Every other Phantom is an I band.

yeah the same way a Cr.42 can beat a F-15J

feel free to test any jet of your choosing against my MiG-21bis

1 Like

Mad that someone pointed out you were wrong? :-)

A) Customs are irrelevant to game balance discussion you ketchup drinker due to nature of being custom battles. Also thats why i said

B) F-104J(10.3), F-104S and F-104S (both 11.0) really arent

(to be absolutely pedantric no F-104 is at 9.7, A and C sit at 9.3 in RB).

Both S and TAF get actual flares.

Mention me if he takes up your challenge.

How do you know it’s an F-4 track?

This is what GJ says…

SPO-10 doesn’t detect radar signals with PRF lower than 800 Hz and higher than 8000 Hz, which means that it can’t detect MPRF and HPRF pulse-doppler signals.
As such not SPO-10 not detecting AIM-7F launches in Simulator battle are intended.
However, we plan on updating the info cards for RWR to reflect different game mode.](Community Bug Reporting System)

APQ120 works at about 9.7GHz, so…
Interestingly enough, SPO10 picks up ZSU23 and 2S6 normally, both of which work in Ku band (J) and they regularly show on SPO10’s display in Test flight.

IMO, GJ is doing a shitty job of attempting to “balance the game” ™, something they often do where nobody asks them to do so.

The APQ-120 / APG-59, really the Aero 1A FCR derivatives and some other radars that were in service alongside the Conical Scan seeker equipt Sparrows (AIM-7C / -7D / -7E / -F) don’t use Pulse Doppler derived waveforms for Sparrow guidance, that’s exclusively used by the Teen series of fighters(except for the F-14 & F-16A-15ADF), they use a (Frequency modulated)Continuous Wave illuminator (see the trumpet waveguide in the subsequent photo) and and as such why they don’t detect the launch signal being generated, because there is no Pulse Repetition Frequency used for range & range rate encoding.

The Pencil requires a scrifice.

Not sure what you mean…care to elaborate?


There are two types of Sparrow Guidance Waveform;

(FM-)CW, Frequency Modulated Continuous Wave


PD-ILL / PDI, Pulse-Doppler Illumination

In short the issue is that FM-CW due to being a continuous signal doesn’t have a PRF (A property of of the encoding / Waveform, separate to the Carrier frequency of the FCR)

and otherwise the PDI Waveform is outside the Scanned range of the SPO-10.

Its not too dissimilar to the MiG-23’s tracking signals being outside the AN/ALR-45’s receiver range and so many western aircraft not being able to detect it.

SPO10 works in X/Ku band, same as APQ120.
What can an APQ120 do that SPO10 can’t see?
I mean, PRF of little relevance if the RWR can pickup the carrier wave.
Ok, it may not recognize the exact mode, but it most certainly can recognize the presence of the active radar.

There is a second Traveling wave tube and antenna setup specifically for Sparrow guidance that can and does operate independently of the Radar. the radar is used to point the co-axial horn Antenna towards the target.

How exactly do you think radar modes are characterized?
In order to be able to tell the difference between Search, Track and Guidance waveforms?

That depends on how the RWR is actually doing the processing and the particulars of each filter / check / each entry in the look up table;

In the SPO-10’s case it may well be discarding the returns due to the PRF being outside its range, or discarding the returns for any number of potential reasons.


How can PRF be outside SPO10’s range, when it’s several orders of magnitude lower than radar frequency?
SPO10 is a rather primitive device with little, if any filters, so it’s gonna pick up pretty much anything within and on the fringes of its op.freq.band and just toss it at the pilot in the cockpit, to figure out what’s what.

I know, but dunno much about it.

Due to the second pulse either, occurring outside the reference frame if the rate is too low, or an inability to sample the returns sufficiently to make a determination due to bleeding into adjacent sample timesteps if the rate is too high (and further reducing the effective Duty cycle and and so reduce the apparent received energy) and so cause issues with signal detection and classification.

It doesn’t matter how analog or digital the system is, it is still composed of tuned circuits and so has to chose between resolution or a wide spectrum, and since there are limits imposed on the resolution for workable classification of the signals, the width of the received spectrum is thus also limited.

Yeah, ok, but we’re talking about CW here.
It’s most likely the highest PRF allowed by a carrier frequency, so it’s well within SPO’s range.
I mean, what’s the point of a CW if it’s PRF is below H band? The resolution becomes way too low for the AAM guidance.

That makes no sense, PRF is used by pulse systems to demine the maximum unambiguous range / range rate that a target can have before it becomes ambiguous (e.g. second time around returns) or gets lost in clutter (staggering the pulses or interleaving has a number of tradeoffs).

The issues with a low PRF becomes one of polling, where target returns are not gathered often enough to be sufficiently useful, Where High PRF’s have issues with low efficiency (power) and range.

A continuous wave cannot have a PRF, it is in the name; the signal is either Continuous or pulsed not both, CW is effectively a special case where the waveform has an 100% duty cycle / pulse width (the same way a square is a special form of rectangle), so with a single transceiver element there is no time left to listen for the returns in any given cycle.

Ok, we getting sidetracked here…of course the CW has PRF, it’s just 100% of what TWT is giving out, as you correctly concluded later, in your own words…and radar in CW mode doesn’t listen, SARH missile does.

Anyway, this is the theoretical background behind SPO10’s practical ability to pickup search, TWS, STT, or CW signals in its operating bandwidth.

It doesn’t matter if it can or can’t pickup CW / Tracking emissions since it can’t differentiate between the two, which is why it doesn’t have a separate dedicated launch warning, since detecting a Track or Launch signal would need to be respected and conservatively interpreted as a launch warning to avoid issues.

This was an issue with the F-15 (PDI Sparrow / AMRAAM guidance) / Tornado for a period of time.

Also the fact that auxiliary Sparrow launch methodologies that did not rely upon the radar for Antenna training Error correction are not (yet) implemented, makes the point almost entirely moot in effect due to most aircraft lacking sensors or the ability to independently employ them and as such a radar track must precede launch, even though this was not true in many cases.

e.g. F-14 via IR / EO / IIR sensor(s)

Well, it DOES matter since neither track, or CW are available in game and they should be.
That’s the point of this whole discussion. Also, SPO10 doesn’t recognize launching sequence, but a skilled pilot can figure it out, on his own, since the RWR has next to none filters.

I don’t think they are ever going to add an aural channel to RWRs since that’s towing the line on accurate portrayal of tactics, let alone modeling it for modern, or current systems across the threat spectrum, that would need far more technical information, let alone each specific system’s modes of operation.

Yeah, but it’s not that important after all.
However, SPO10 should really get back its fundamental use, since, as it is, Bis is rather useless in Sim Air, particularly in EC.