5 ms·

Anti-radar devices will have to go the Russian route and just blast the shit out of every frequency to disrupt radar. It won't help that the radar is shifting f

Anti-radar devices will have to go the Russian route and just blast the shit out of every frequency to disrupt radar. It won't help that the radar is shifting frequencies over time if every channel and frequency is filled with strong noise from a jammer.

vonmoltke 11y ago
Barrage noise jammers (to which you refer) have always been the most difficult jammers to deal with in the sensor. The usual countermeasure to them is "region blanking", where the sensor simply stops listening for returns on the azimuth of the jammer. Fortunately, barrage noise jammers are the easiest to deal with using AGM-88 HARMs. Edit: Also, I should note that barrage noise jammers have limited bandwidth, and have to trade off bandwidth for power. If the APCN system keeps its operating frequency sufficiently masked it may require multiple jammers to actually interfere with the system sufficiently.
- wlesieutre 11y ago
  > The AGM-88 High-speed Anti-Radiation Missile (HARM) is a tactical, air-to-surface missile designed to home in on electronic transmissions coming from surface-to-air radar systems. Figured that's what it was, but I'll save everyone the googling.
dogma1138 11y ago
Well not really.... 1) Jammers are a realy good target for anti-radiation missiles. 2) Jammers are also limited in power and frequency you can't make a jammer that can saturate every frequency multi-spectrum jammers allow you to jam different frequencies but usually not at the same time because you are power limited. So even if you have a jammer with say 50 different physical transmitter if you operate all of them each transmitter will operate at 1/50th of the peak transmission power. Wide spectrum jamming is usually done using timing, radars send pulses based on some specific cycle so what you do is attenuate your jammer to the cycle and frequency which allows you to "effectively" jam multiple radars because you don't have to be transmitting all the time to create false signals. So this (#2) is what this whole new "encrypted radar" concept is supposed to combat which is cheap and effective wide spectrum radar jammers because today anyone with an SDR and a hacked TV dish can make quite an effective jammer.
- giardini 11y ago
  "Jammers are a realy(sic) good target for anti-radiation missiles." Yes, but jammers are cheap and lightweight; missiles are expensive and bulky. And there are other types of jammers that mimic a target: they listen for a radar ping and respond with the simulated target's echo. Such jammers are smarter, more difficult to ignore, and more expensive but they still cost far less than a missile (and weigh far less too).
  - vonmoltke 11y ago
    Barrage noise jammers with sufficient power and bandwidth to effectively shut down radar systems are neither cheap nor lightweight. The ones that are both are merely a nuisance.
    - giardini 11y ago
      You're right. I spoke too soon. I was thinking of _decoys_, which are typically cheap, light and inexpensive and provide, in the most optimistic of circumstances for the target, a multitude of other indistinguishable "targets."
jasonwatkinspdx 11y ago
It's not as effective as you imagine. Noise radar can still operate when the return signal is below the noise floor. It's very difficult to jam because the jamming is uncorrelated with the noise signal. The low power levels make it harder to detect even with modern direction finding / interferometry arrays.

vonmoltke 11y ago

Barrage noise jammers (to which you refer) have always been the most difficult jammers to deal with in the sensor. The usual countermeasure to them is "region blanking", where the sensor simply stops listening for returns on the azimuth of the jammer. Fortunately, barrage noise jammers are the easiest to deal with using AGM-88 HARMs. Edit: Also, I should note that barrage noise jammers have limited bandwidth, and have to trade off bandwidth for power. If the APCN system keeps its operating frequency sufficiently masked it may require multiple jammers to actually interfere with the system sufficiently.

wlesieutre 11y ago
> The AGM-88 High-speed Anti-Radiation Missile (HARM) is a tactical, air-to-surface missile designed to home in on electronic transmissions coming from surface-to-air radar systems. Figured that's what it was, but I'll save everyone the googling.

dogma1138 11y ago

Well not really.... 1) Jammers are a realy good target for anti-radiation missiles. 2) Jammers are also limited in power and frequency you can't make a jammer that can saturate every frequency multi-spectrum jammers allow you to jam different frequencies but usually not at the same time because you are power limited. So even if you have a jammer with say 50 different physical transmitter if you operate all of them each transmitter will operate at 1/50th of the peak transmission power. Wide spectrum jamming is usually done using timing, radars send pulses based on some specific cycle so what you do is attenuate your jammer to the cycle and frequency which allows you to "effectively" jam multiple radars because you don't have to be transmitting all the time to create false signals. So this (#2) is what this whole new "encrypted radar" concept is supposed to combat which is cheap and effective wide spectrum radar jammers because today anyone with an SDR and a hacked TV dish can make quite an effective jammer.

giardini 11y ago
"Jammers are a realy(sic) good target for anti-radiation missiles." Yes, but jammers are cheap and lightweight; missiles are expensive and bulky. And there are other types of jammers that mimic a target: they listen for a radar ping and respond with the simulated target's echo. Such jammers are smarter, more difficult to ignore, and more expensive but they still cost far less than a missile (and weigh far less too).
- vonmoltke 11y ago
  Barrage noise jammers with sufficient power and bandwidth to effectively shut down radar systems are neither cheap nor lightweight. The ones that are both are merely a nuisance.
  - giardini 11y ago
    You're right. I spoke too soon. I was thinking of _decoys_, which are typically cheap, light and inexpensive and provide, in the most optimistic of circumstances for the target, a multitude of other indistinguishable "targets."

jasonwatkinspdx 11y ago

It's not as effective as you imagine. Noise radar can still operate when the return signal is below the noise floor. It's very difficult to jam because the jamming is uncorrelated with the noise signal. The low power levels make it harder to detect even with modern direction finding / interferometry arrays.