DF of Noise generators (jammers) , in particular anti-drone, anti-mobile jammers?

Hi Kraken, thanks a lot for achieving a really professional approach and sharing huge work with the people.
The question is:

  1. Does it matter if a jammer has chaotic/special phase modulation and/or white noise spectrum distribution - will the KrakenSDR find such jammer and how it will affect on detection accuracy in this case?
  2. Is the KrakenSDR mostly applicable for DF of anti-drone, anti-GPS, anti-mobile jammers?
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IIRC most common COTS drones like a DJI operate on the same ISM band as wifi - so near 2.4 and 5 GHz. Unfortunately the Kraken can’t go past 1766 MHz, or 1.7 GHz. If you want to DF a drone, you’ll probably have to use a WiFi yagi and something like an Ettus B200 or an ADALM Pluto to get your LOBs.

As for GPS, in theory you could as GPS operates under that 1766 MHz limit. I personally have never used it for this purpose, and you’d have to get five identical SMA GPS antennas.

In terms of cell phone/radio handset jammers then as long as its under that 1766 MHz limit then you could probably DF those emitters. So a jammer jamming the 850 band of GSM could be detectable, but probably not the 1800 band. Just know that any man-packable solution may have an antenna array either too big and unwieldy to transport, or too small to be highly accurate, requiring more LOBs and thus more movement.

That being said IIRC the Kraken doesn’t demodulate a signal, just finds where it’s coming from so I don’t believe modulation will be an issue. May be wrong though.

Thank you w122!
Yes I meant jammers under 1766 Mhz, those for 433-866 Mhz and GPS.
I supposed that not the kind of a usual modulation itself, but the quick intentional chaotic sharp phase “bouncing”, will hinder Kraken’s DF algorithm.
If not, it would be perfect.

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Correct. KrakenSDR does not demodulate when using the DOA application.

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The modulation doesn’t really matter. The main issue is the possible use of spread spectrum or hopping signals. If the jammer signal is hopping all over different frequency bands, the Kraken will only be able to track it when it hits an active VFO frequency set in the Kraken web gui.

A simple jammer would just be transmitting a strong blocking signal on those frequencies, so yes it would be no problem to find the jammer. If it’s some sort of more sophiscated frequency hopping jammer, it might be a bit more difficult.

Also as others mentioned, the top end frequency of the KrakenSDR is 1.766 GHz, and at frequencies above about 1 GHz you do need to be quite precise in the manufacturing and use of your antenna array and cabling.

Thank you very much)

HI people)) Let’s say I want to find the source of a constant signal from a GPS jamming device (1227.6 MHz and 1575.42MHz), at what distance the Kraken will find it in an open area if the antenna array is on the roof of the car, and how much the direction finding range will increase if the antennas are raised 5 meters above the ground. I also saw in the video where the Kraken’s antennas are installed on the roof of the house and a direction finding range of up to 30 km sounded in it, can the Kraken take direction in such a static position?

Hi, knowing the range is quite a difficult question to answer as it entirely depends on specific local parameter’s, like the terrain, height of the TX, power of the TX etc.

For perfect line of sight, you can always use path loss formulas to calculate received power. Of course at 1.2, 1.5 GHz there is more path loss, and more loss from blocking objects. The goal with raising the antennas off the ground would be to achieve better line of sight to the TX.

As long as the signal can be received with good line of sight you can get a bearing on it.

One more question if possible) I signed up with Tim Chapman ( Owner, Arrow Antenna, LLC ) and he said that their array of 440 MHz dipole antennas ( Kraken Software Defined Radio Antennas ) could handle the bearing at GPS frequencies.

Here is his answer - … Please confer with the maker of the Kraken SDR. That is Carl Laufer. I think our 440MHz elements will work for that, but I would want his opinion…

So your opinion is extremely important
P.S. As far as I understand, Carl Laufer is you ?

Yes that’s me, but I think he misunderstood. The 440 MHz elements can be used for higher frequencies (e.g 800 MHz), but for GPS at 1.575 GHz that is pushing it too far out of spec.

For 1.575 GHz you will need a more accurate array and precisely cut cables. There’s probably no commercial array solution available for those frequencies. Use the excel spacing calculator, and then you can lay out 5 SMA’s on a PCB design. Then tune five 1.575 GHz whip antennas for it.

For the cables I’m afraid it’s probably either expensive phase matched cables, or hand tuning a set yourself with a VNA.

Thank you very much for answers