[miketery]

This article is sparse on details.

How much energy, how long is the pulse, how close were the drones?

Regardless I think the primary challenge with these systems will be energy on site and a surge of it during waves of attacks. Charged up capacitors can only handle so many waves.

[hwillis]

> How much energy, how long is the pulse, how close were the drones?

1 millisecond pulses and 70 kW continuous usage[1] which is roughly equivalent to the AN/TPQ-53[2]. 2 km range.

> Regardless I think the primary challenge with these systems will be energy on site and a surge of it during waves of attacks. Charged up capacitors can only handle so many waves.

That is not how this kind of thing works. Capacitors are a terrible energy source. Their voltage drops off exponentially as they discharge and almost all electronic are very particular about the voltage they require. A railgun wants current and does not care about voltage. Radio transmitters care a lot about voltage.

Regardless, a 70 kW generator fits on a small trailer. Smaller than the weapon itself. It will run for days on a good sized tank of diesel.

[1] https://www.twz.com/land/army-puts-50m-bet-on-next-gen-leoni...

[2] https://en.wikipedia.org/wiki/AN/TPQ-53_Quick_Reaction_Capab...

[topspin]

> Regardless, a 70 kW generator fits on a small trailer. Smaller than the weapon itself. It will run for days on a good sized tank of diesel.

At full load and a thermodynamic efficiency of about ~31% a 70kW generator is about 300hp mechanical. Those fit on a trailer. Not a "small" trailer. A dual axle type trailer with ~1.3 tons of capacity (Cummings C70D2RE.) Military generators tend to be heavier than commercial units. It will burn about ~175 gal/day of diesel, so yes a "good sized" tank about: about ~3.2 55 gal drums every day.

Now, they're imagining "625 element" systems for adequate coverage of a high value site, like an air base. About 2000 bbl/day. That's a little more than 10 large tanker trucks of fuel.

Logistically non-trivial. The Russian's have learned that large fuel trucks are short-lived in drone-dense environments.

Of course, that all for 100% 24/7 operation. I suspect that any real system will quickly become adept at running far less than 100%.

[bigiain]

> Capacitors are a terrible energy source.

They're a pretty good way of storing energy in a way you can deliver it _really really_ fast. Sure, not in a way your carefully designed electronic circuits can make use of it, but if you need a really really big ZAP! capacitors are a reasonable option. After all, clouds and dirt are not the most efficient choice for capacitor plates, and air is not an ideal dielectric, but lightning goes ZAP! quite satisfyingly.

As I posted elsewhere here,you might enjoy Lightning On Demand's Lorentz Cannon: https://www.youtube.com/watch?v=lix-vr_AF38

[WastedCucumber]

I was wondering the same thing, but haven't found much. Sounds like it's only ever been a mobile installation - on a trailer, stryker, and a ship. Except for the ship, that probably means a relatively limited power supply. And its limited range probably means that stationary installations don't make much sense.

Sure seems like NATO would love to get a hold of some of these.

[giantg2]

Potentially collateral damage too. You zapped some drones 100 yards away, but what about that airplane a couple miles out?

[hwillis]

Cruising altitude is ~40k feet or 12 km and the range of the weapon is 2km. The system only works because of all the exposed wiring on quadcopters; everything in a plane is enclosed in a highly conductive aluminum shell and is very well protected. The windows are large enough to let in microwaves, but not very well. Some antennas might be in danger but in general planes are built to survive lighting. It would be a real freak accident for something to break.

[giantg2]

I'd be more concerned about small planes or other drones. But if a little shielding fixes it, then this will quickly be obsolete as it's trivial to dd shielding if you're a malicious actor.

[JumpCrisscross]

> what about that airplane a couple miles out?

Are these Masars? If not, square cubed to the rescue.

[hwillis]

Lasers and masers are not inherently collimated or straight lines. The only thing specific to lasers/masers is that all the light is the same wavelength. Beam, parabolic and phased antennas are all very capable of making much tighter beams than your average laser.

In fact at the limits of performance lasers (and particularly masers) are quite bad at generating straight beams, because they are quite small sources of light and divergence is inversely proportional to the width of the emitter. It is a misconception that they are low-etendue.

[mitthrowaway2]

Lasers are coherent emitters, which means that they behave like a perfect point source and the beam forming is limited only by diffraction. The collimation is limited only by the lens diameter and quality.

[giantg2]

I assumed they would be masers or at least something with high directional gain. Otherwise your zapping a bunch of other stuff. Someone else said it's only a 2km range.

[bigiain]

And also - what about the payload that drone was delivering, aimed at the target and doing 150kmh or more when your microwaves zapped it and killed off all the electronics. It'll only take it 2 unpowered/unguided seconds to cover that last 100m, so it'll have dropped 20m on a ballistic trajectory. It won't have hit your tank right in the crew hatch, but it's still delivered its explosive way too close for comfort. Perhaps not a problem if the target is an armored vehicle, but it'll probably still set your ammunition store or fuel dump on fire.