RFDefence®

Jamming effects estimation for typical applications

Views: 164 Author: Trayman Publish Time: Origin: RFDefence®

In theory, the jamming effect's estimation is a theoretical value based on the premise of the ultimate vacuum environment without any barrier. And the estimates can only provide a concept of order of magnitudes, but the real jamming effect is subject to the field test.


Many factors can easily influence the radiofrequency equipment, for example, the different altitudes, different seasons, the density and height of buildings and surrounding vegetation, the weather condition like raining or sunshine days, etc. The working environment strongly affects the RF signal transmission, so it is hard to provide a standard to identify accurate coverage. It must be subject to the actual transmission and working environment. Or the application engineer can have references on the existing coverage models (like Ericsson's suburban Chicago model).


1.1 Interference effects upon Improvised Explosive Devices (IED) 

As VHF and UHF systems, jamming frequencies are usually working as interference frequencies on IED jamming projects. Still, to a great extent, it must satisfy certain conditions: The Jammer will take effect only when they have a certain distance among the controller, Jammer, and IED. We have never heard any better solutions without these premises.


ECM-Electronic Countermeasures, Counter IED - Illustration

LD-Ld >6

RemoteJammer 1Jammer 2Jammer 3
12.5KHz, 1W1MHz, 100W(1.25W)10MHz, 100W(125mW)100MHz, 100W(12.5mW)
Distance (m)Ld (m)Ld (m)Ld (m)
1051.5

0.5

20103.21
502582.5
10050165
2001003210
5002507925
100050015850


1.2  Off-network Walkie Talkie Jamming

We take field intensity suppression as an example to explain the difficulty with interfering Off-network Walkie-talkie as follows:

Military Convoy Bomb jammer - Active by a Walkie-talkie - Illustration

RemoteJammer 1Jammer 2Jammer 3
12.5KHz, 1W1MHz, 100W(1.25W)10MHz, 100W(125mW)100MHz, 100W(12.5mW)
Distance (m)Ld (m)Ld (m)Ld (m)
1010.4

0.2

2020.70.4
5061.81.1
100113.62.2
200227.14.4
5005617.911.1
100011135.722.2


1.3 In-network Walkie-talkie Jamming

The working-mode for in-network walkie-talkie is similar to Public Cellular Mobile system.

Interference upon Pubic Cellular telecommunication system

 

1.4. Public cellular mobile system Jamming

Please refer to DCS1800 as an example as follows. 3G and 4G systems for 1800MHz adopted spread spectrum anti-jamming system which leads more complicatedly on theory estimation, therefore the anti-jamming effect gets good than DCS 1800MHz system under the same frequency range and bandwidth. 

Mobile Jamming System - Example

1.5 Drone Jamming

The interference upon UAV gets more complicated, as it mainly relates to the below factors:

Clarify main purposes: general interference (Interfere Video, Interfere Control part or kill it down)? Or capture (It should be totally different device if need to capture UAV).


Typical test application should be: The distance between Controller and UAV is much further than the distance between Jammer and UAV.

Drone Jamming System - Example

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