Radio signal jamming countermeasures

Think in terms of a fictional military application:
If radio signals are being intentionally jammed what can be done to overcome it?
Somethings come to mind:

  • Destroy/disable jamming technology
  • Boost power of transmitter
  • Multiple transmitters
  • Closer transmitters

I really need to stretch the limits of what really can be done here.

This is a subject of considerable real-world military interest.

This may not fit what you’re looking for but for years Cuba has been jamming radio and tv signals from the US. Their jamming equipment is usually carried in boats, consequently Cubans know that times of bad weather are ideal for watching US broadcasts because the boats can not be at sea.

More recently Cubans have taken to building illegal receivers/decoders for satellite signals and get the US channels that way, for some reason it does not appear that the Cuban government can jam satellite signals.

Both these methods do not overpower or disarm the jamming, but rather circumvent it.

What is being jammed,voice,morse(I know thats old hat but you might be writing a story set in the past)or what?

Voice, data, and keeping with the fictional application power over the air.

My advice will be out of date but some of it might be useful.

Burst tx. is very,very difficult to jam because of its incredibly short transmission time(fractions of a second if you’re using top of the range) remember to jam you the baddies have to know what are using though they could use broad spectrum jamming.

They may not want to use this because it may interfere with their own comms.or it may annoy third parties that they dont wish to annoy(powerful neutrals maybe)by interfering with their comms.

Also you must bear in mind the system you’re transmitting over,VHF radio waves are mostly directional,line of sight(with part of the signal following the contours of the ground) and are comparitivly short range.

HF used for long range will be aimed at and bounced off of the ionosphere,and can if aimed right circumnavigate the globe.

To get through when theres a jamming threat you could use massive power but its not favourite.

Use freq.hopping tx,message sent in continuous sequence but split into tiny portions on changing freqs.
I expect that this hasn’t been overly helpful in todays terms but it might give you a starting point for your ponderings.

I’ve experienced hostile jamming quite often in the past and you can actually work through it
(Or could back in the stoneage when I was doing it)
Good luck.

Radar Jamming

Raspberry! I HATE raspberry!

Depending on circumstances, you can circumvent RF jamming with laser emitter/detector equipment.

A “satellite dish” is a highly directional antenna. It has a very small “field of view,” so to speak, and therefore it needs to be aimed carefully at the satellite. This means it’s not affected by a transmitter outside that field of view. A really powerful jamming signal may be able to overcome it, but it’s much harder than jamming a terrestrial TV signal.

You can do the same on earth, of course - use highly directional microwave antennas to avoid jamming. But microwaves only travel straight, so it’s only good for line-of-sight communications. If even that is jamming, you can switch to optical communication (modulated laser beam).

Boosting power is not a good way to overcome jamming - unless it’s a really BIG boost in power.

The basic rule is this: Picture an S-Meter on a radio. The signal is reading S-7. The guy who is talking says he is transmitting with 50 watts. For his signal to move to an S-8, he would have to increase his power to 100 watts. To increase to an S-9 the power output would have to be 200 watts! Every increase of 1 S-unit requires a doubling of output power.

The receiving antenna and the sensitivity of the receiver does more than a transmitter power increase. And when the transmitting station in the USA is transmitting 10,000 watts, and a jamming station in Cuba is completely covering that signal, you would conservatively need 300,000 watts to even start to overcome the jamming.