AN/APG-77 vs DRFM jammer

avon1944 wrote:A B-52 (or a Tu-95, etc.) with banks of broadband jammers plus lots of power. Jamming that covers entire spectrums. In that case, the jamming source would have to eliminated.

wrightwing wrote:The only way you could jam the APG-77/81, is to have enough emitters to cover the entire frequency spectrum, and at this point you become a pretty obvious target. The most you could hope for is to degrade their performance, and that would still require a large number of frequencies being jammed.
There's no way that the jammer could predict the next frequency the radar would be operating on, and the ESM systems would likely detect the jamming if there was any variance from the original signals. Another thing to consider is that the radar would only need be used very sparingly, due to very fast search rates, ESM systems, and 3rd party targeting information. When combined with LPI, it would prove very challenging to counter.

Airborne detection of stealth aircraft may already be an operational capability. In a series of tests at Edwards AFB, Calif., in 2009, Lockheed Martin’s CATbird avionics testbed—a Boeing 737 that carries the F-35 Joint Strike Fighter’s entire avionics system—engaged a mixed force of F-22s and Boeing F-15s and was able to locate and jam F-22 radars, according to researchers.

The effectiveness of a modern fighter radar is determined by a combination of its radiating power and Low Probability of Intercept (LPI) features that prevent the radar from tripping off alarm systems in a target. These typically include using a narrow beam that is hard to spot from off its boresight; only transmitting radar pulses when necessary; spreading the radar pulses over a wide band so there will only be a very small signal on any one band (Frequency Hopping); or varying transmission parameters such as pulse form, frequency, or PRF, jumping around in an unpredictable fashion, not staying in one place long enough to register.

The radiated power is largely dependent on the antenna aperture.

Increasing the radiated power will increase the range of the radar but unless it is accompanied by LPI it will also announce the presence of the radiating aircraft to sensors on an enemy fighter that still does not have you in its radar range.

In an AESA radar individual TR modules can be assigned the role of Radar Warning Receivers allowing a radiating aircraft to be picked up the target aircraft, instead of the other way around!

For example, the AN/APG-77 fitted on the F-22 Raptor has 2,000 TR modules. Operating purely as an RWR it can pick up enemy aircraft's radar from distances of up to 460 kilometers (250 nautical miles). The higher the energy radiated by the enemy aircraft radar, greater the APG-77's detection range. With all modules operating as radars, the APG-77 can acquire pick enemy targets up to 220 kilometers (125 nautical miles). Its use of LPI does not alert the enemy aircraft to its own presence.

Broadly speaking Russian radars tend to rely on radiated power for their effectiveness, leveraging the higher apertures of their radars facilitated by larger aircraft size and nose cross sectional area. American AESA radars blend radiating powere with LPI. Their higher software maturity levels facilitate use of the AESA for communication, gathering information electronic intelligence, locating electronic systems, classifying them, and warning the pilot of possible threats or high-priority targets.

SpudmanWP wrote:The problem with that news story is that nothing was said about what modes the -77 was using (eg max range, max LPI, etc).

popcorn wrote:

SpudmanWP wrote:The problem with that news story is that nothing was said about what modes the -77 was using (eg max range, max LPI, etc).

I'm surprised they disclosed the story in the first place.

able to locate and jam F-22 radars

delvo wrote: My guess is that it's like shining a light in your enemy's eyes in an otherwise not-so-bright or dark environment: (s)he might be too blinded to see anything anywhere for a while, or might only be unable to look at things too close to the direction of the light source

tacf-x wrote:The "damage" part was referring to speculation that the F-22's radar may be able to serve as a directed energy RF weapon to overload enemy electronics like a portable E-bomb/EMP weapon. Whether or not an F-22 can do this in real life I have no idea. If it could it may still not serve as a viable DEW due to the issue that the radar can only shoot an energy beam in front of it in a + or - 60 degree arc in elevation and azimuth. With no turret it won't be able to aim very well.

delvo wrote:Sometimes I do wonder exactly what F-22s have that we're hiding from foreigners that F-35s don't have.[\quote]

Ranges of the new lines of AESA radars are classified. But they are estimated at about 90 mi. for the smallest (aimed at the F-16 radar-upgrade market). The F/A-18E/F and F-35 (with radar ranges of 100 mi.) are followed by the F-22 (110-115-mi.). The largest is carried by the upgraded F-15Cs and Es (125 mi.). By comparison, the range for a mechanically scanned, F-15C radar is 56 mi. according to Russian air force intelligence. U.S. aerospace officials agree that an AESA radar "at least doubles" the range over standard military radars.

When coupled with the electronic techniques generator in an aircraft, the radar can project jamming, false targets and other false information into enemy sensors. Ranges for electronic attack equal the AESA radar plus that of the enemy radar. That could allow electronic attack at ranges of 150 mi. or more. The ability to pick out small targets at a long distance also lets AESA-equipped aircraft find and attack cruise missiles, stealth aircraft and small UAVs.

thestealthfighterguy wrote:

delvo wrote:Sometimes I do wonder exactly what F-22s have that we're hiding from foreigners that F-35s don't have.[\quote]

Ranges of the new lines of AESA radars are classified. But they are estimated at about 90 mi. for the smallest (aimed at the F-16 radar-upgrade market). The F/A-18E/F and F-35 (with radar ranges of 100 mi.) are followed by the F-22 (110-115-mi.). The largest is carried by the upgraded F-15Cs and Es (125 mi.). By comparison, the range for a mechanically scanned, F-15C radar is 56 mi. according to Russian air force intelligence. U.S. aerospace officials agree that an AESA radar "at least doubles" the range over standard military radars.

When coupled with the electronic techniques generator in an aircraft, the radar can project jamming, false targets and other false information into enemy sensors. Ranges for electronic attack equal the AESA radar plus that of the enemy radar. That could allow electronic attack at ranges of 150 mi. or more. The ability to pick out small targets at a long distance also lets AESA-equipped aircraft find and attack cruise missiles, stealth aircraft and small UAVs.

http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=awst&id=news/aw020909p2.xml&headline=null&next=0

I thought this quote and link could help. Most people don't know the F-22 can do these things and it can do alot more. King of the sky baby! TSFG