4 ms·

Jamming is a mixed bag, because a) you lose your own drone capability in that area and b) you broadcast a loud beacon that says "HERE IS THE APPROXIMATE LOCATIO

Jamming is a mixed bag, because a) you lose your own drone capability in that area and b) you broadcast a loud beacon that says "HERE IS THE APPROXIMATE LOCATION OF A HIGH-VALUE ASSET". The Ukrainians have had some big wins from triangulating weird-looking RF signals and unleashing hell on whatever is radiating it - you can jam a drone, but you can't jam a 155mm shell.

Manuel_D 3y ago
Jamming can avoid "friendly fire" through a variety of means. Directional antennas can emit RF in the direction of the enemy, but not your own assets. You can also jam on different frequencies than you're using to operate your own drones.
- scrps 3y ago
  That and larger drone comms for russia I would guess are satellite based which is harder to jam and sadly out of budget for the Ukrainians. That being said I wonder if you could control small drones over satellite or if that is a $900 solution to a 99 cent problem.
  - Manuel_D 3y ago
    Satellite communications also has the issue of bigger form factor and larger power requirements. Not an issue for a predator drone, but your DJI isn't going to be using satellite comms any time soon. The more promising areas are optical communications (but this has issues with fog and atmospheric attenuation), or directional antennas. Like, a yagi on a gimbal constantly pointed at the control station.
- _ea1k 3y ago
  That's all fine and dandy, but if you can use the source to approximate a location, you can hit it with himars. Alternatively, send gps guided drones with optical targeting. If the jamming system has inadequate air defenses, it might not be jamming for long.
- jdietrich 3y ago
  >You can also jam on different frequencies than you're using to operate your own drones. That's an arms race with exactly one step. If you're using a commercial system, then you're using FHSS across the whole of the 2.4GHz ISM band for your control link and most of the 5.8GHz band for digital VTX. If you're designing a system for military applications, then either you use SDR to go frequency agile across everything from VHF to the S or C band, or you're in the wrong job. The Nash equilibrium is for everyone to use all practical frequencies all of the time and the technology to do that is largely mature. >Directional antennas can emit RF in the direction of the enemy, but not your own assets. How directional? If it's very directional, then you've got a drone gun, which relies on you being able to see and track incoming drones. If you can see and track, you've already solved the hard part and making a hard kill is comparatively easy. If it isn't especially directional, then you've created a conical area of denial that is only marginally more problematic for your enemy than for yourself and still fairly easy to triangulate. There is maybe a viable strategy of coordinating the frequency hopping of your jammers and your drones and using a distributed network of low-cost jamming transmitters to avoid painting a target on your own back, but it's well beyond the technological capabilities or the budget of either Russia or Ukraine. I have no doubt that DARPA are working on something along those lines, but the base rate probability of a DARPA project actually getting to the battlefield is fairly low. For my money, the near-future of counter-drone technology is kinetic. The Flakpanzer Gepard was considered obsolete a decade ago, but it's arguably the most valuable asset in the Ukrainian arsenal for dealing with drone threats. Most current hard-kill active protection systems should be fairly straightforward to upgrade to reliably deal with loitering munitions.
  - Manuel_D 3y ago
    Regarding directional antennas, I'm referring more to a log periodic antenna that roughly directs RF in a 45-60 degree arc [1]. Placed around the perimeter of a base, there's enough directivity that an incoming drone is being hit with 100-1,000x more RF energy than things inside the perimeter. It's not a "drone gun", it's still jamming an area. It's just wedge shaped area facing away from you. And yeah, the most effective way of avoiding EF friendly fire is spread spectrum communication where the jammer is synchronized to avoid the frequencies being used for communications. But that can be tricky to set up, since you have potentially many different radio systems with their own spread spectrum scheme. 1. https://www.tutorialspoint.com/antenna_theory/images/uni_directional_log_periodic.jpg https://www.tutorialspoint.com/antenna_theory/images/uni_dir...
scrps 3y ago
you can jam a drone, but you can't jam a 155mm shell. This is both a fantastic line and wisdom.

Manuel_D 3y ago

Jamming can avoid "friendly fire" through a variety of means. Directional antennas can emit RF in the direction of the enemy, but not your own assets. You can also jam on different frequencies than you're using to operate your own drones.

scrps 3y ago
That and larger drone comms for russia I would guess are satellite based which is harder to jam and sadly out of budget for the Ukrainians. That being said I wonder if you could control small drones over satellite or if that is a $900 solution to a 99 cent problem.
- Manuel_D 3y ago
  Satellite communications also has the issue of bigger form factor and larger power requirements. Not an issue for a predator drone, but your DJI isn't going to be using satellite comms any time soon. The more promising areas are optical communications (but this has issues with fog and atmospheric attenuation), or directional antennas. Like, a yagi on a gimbal constantly pointed at the control station.
_ea1k 3y ago
That's all fine and dandy, but if you can use the source to approximate a location, you can hit it with himars. Alternatively, send gps guided drones with optical targeting. If the jamming system has inadequate air defenses, it might not be jamming for long.
jdietrich 3y ago
>You can also jam on different frequencies than you're using to operate your own drones. That's an arms race with exactly one step. If you're using a commercial system, then you're using FHSS across the whole of the 2.4GHz ISM band for your control link and most of the 5.8GHz band for digital VTX. If you're designing a system for military applications, then either you use SDR to go frequency agile across everything from VHF to the S or C band, or you're in the wrong job. The Nash equilibrium is for everyone to use all practical frequencies all of the time and the technology to do that is largely mature. >Directional antennas can emit RF in the direction of the enemy, but not your own assets. How directional? If it's very directional, then you've got a drone gun, which relies on you being able to see and track incoming drones. If you can see and track, you've already solved the hard part and making a hard kill is comparatively easy. If it isn't especially directional, then you've created a conical area of denial that is only marginally more problematic for your enemy than for yourself and still fairly easy to triangulate. There is maybe a viable strategy of coordinating the frequency hopping of your jammers and your drones and using a distributed network of low-cost jamming transmitters to avoid painting a target on your own back, but it's well beyond the technological capabilities or the budget of either Russia or Ukraine. I have no doubt that DARPA are working on something along those lines, but the base rate probability of a DARPA project actually getting to the battlefield is fairly low. For my money, the near-future of counter-drone technology is kinetic. The Flakpanzer Gepard was considered obsolete a decade ago, but it's arguably the most valuable asset in the Ukrainian arsenal for dealing with drone threats. Most current hard-kill active protection systems should be fairly straightforward to upgrade to reliably deal with loitering munitions.
- Manuel_D 3y ago
  Regarding directional antennas, I'm referring more to a log periodic antenna that roughly directs RF in a 45-60 degree arc [1]. Placed around the perimeter of a base, there's enough directivity that an incoming drone is being hit with 100-1,000x more RF energy than things inside the perimeter. It's not a "drone gun", it's still jamming an area. It's just wedge shaped area facing away from you. And yeah, the most effective way of avoiding EF friendly fire is spread spectrum communication where the jammer is synchronized to avoid the frequencies being used for communications. But that can be tricky to set up, since you have potentially many different radio systems with their own spread spectrum scheme. 1. https://www.tutorialspoint.com/antenna_theory/images/uni_directional_log_periodic.jpg https://www.tutorialspoint.com/antenna_theory/images/uni_dir...

scrps 3y ago

you can jam a drone, but you can't jam a 155mm shell. This is both a fantastic line and wisdom.