2. 4 Ghz Jammers

[Keith Evans 3]

I have just been reading some disturbing information on R C Universe about the availability and legality of 2.4 Ghz Jammers. They seem to be able to have a wide range and are capable of bringing down R C planes , even Futaba systems. Has anyone had experience of this ? Has anyone left your club under a cloud recently and are members having more unexplained crashes ? Are there detectors for finding such devices? Can someone allieviate my paranoia?

[Former Member]

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[Keith Evans 3]

HI Percy I am not really into the electronic side of the hobby ,I took the statement at face value from R C Universe.

[Former Member]

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[Olly P]

OK, 2 elements to this. I will start with the simple bit, then cover the tricky bit....

1) This kind of jamming technology is illegal in the UK without some specific licences, or exclusions. for example military bomb disposal or electronic counter measures, used to prevent 2.4 systems being used as triggers.

2) Having said the above - It is relatively simple to build a swamping jammer, parts are generic, designs are many. A swamping jammer simply puts out a LOT of noise and the Rx cannot 'find' the right signal.

OK, reassurance, anyone found using a jammer, illegally, faces stiff penalties......That is about it.

In terms of 'even Futaba' (and I fly futaba) a simple swamping jammer will affect any system. To be more focussed then a lot more knowledge is needed.

Finally, I know RCgroups is mostly US, control of this type of equipment is much laxer accross the pond, but malicious use still harshly punished.

[Keith Evans 3]

Hi Percy I am a complete nerd when it comes to putting links in . All I did was to type "R C universe 2.4 Ghz jammers into Google". Hope this helps.

[KingKade]

Now that you mention it, I did have a crash last week when i did a snap at about 6ft above the strip.

i was sure it wasnt my slow thumbs!!! It must have been a jammer!!!!

KK

[Former Member]

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[Phil Green]

...

Edited By Phil Green on 13/05/2014 10:45:39

[John F]

Please excuse my tone but why do 35meg users think they were always safer? It really is not a safer channel to use at all as you have one tiny sliver of bandwidth which, if something else transmits on that frequency you lose everything. It's like riding a bike down an alleyway, if you meet someone else it will invariably mean a crash.

Modern 2.4ghz kit does not have that issue as it travels down many hundreds of alleyways almost at the same time, hopping from one to the other very very fast. If one alleyway is blocked it simply misses that microsecond and returns in the next alleyway no worse for wear at all.

How can 35meg be any better? Whilst there are critics who believe we have a "junk" spektrum it is nothing of the kind. These jammers have to, almost literally, transmit at the same time on every section of 2.4ghz, blocking every alleyway, at the same time, for a long time. Oh, and probably have to do so within sight of your aircraft too as 2.4ghz is readily absorbed by the environment; hills, houses, trees etc etc.

I would definitely feel better flying any model, never mind a large petrol one, on 2.4ghz than fly anything on 35mhz as it simply isn't as bullet proof as some would think.

[KingKade]

Phil, whys your text disappeared?

[Cyclicscooby]

If you're on 35Mhz, legally flying your plane, any muppet, illegally using a 35Mhz system, on the same crystal, say on a boat, or similar, could easily bring you down.. That wouldn't happen on 2.4

Infact, as I just upgraded to a Dx9, i'm converting the Dx6 to two sprung loaded sticks, and using it on ground based stuff... Tamiya Truck, rc mower, etc...

I'd have no problem flying the Dx9 whilst the Dx6 is being used on the ground.. I wouldn't trust 35Mhz to do that, even on opposite-end crystals...

Luv Chrisie.. xx

[fly boy3]

Hi guys, please don't start a 35Mhz via 2.4 gigs war here, all the op asked was about 2.4Gig jammers info. Cheers.

[Devcon1]

Apologies for straying off topic.

This could be moved onto a different thread but I'm fascinated by the the thought of a radio controlled mower for the garden.

Do you have any pictures or designs Chrisie as this sounds brilliant.

John

[Masher]

In response to the OP. For the paranoid, I'm afraid to inform you that it is relatively easy to jam any RF system! This is especially true if the operating signal frequency is known - as with "our" RC links. However, any form of jamming is totally illegal and would soon attract the attention of the authorities. Are there signal detectors that can identify jammers? Yes there are costing multiple 10's of £k but don't waste your money and anyway you would need "certain credentials" to purchase them! Simple spectrum analysis is cheaper but again, leave your money in the pocket. No I have never experienced any known deliberate jamming of RC.

To put this into perspective, pretty much everything we do is susceptible to compromise from the bad people. At one extreme we have terrorists and just think how easy it would be to make our motor cars into a hidden lethal death trap by a malicious person.

So............ yes there is a risk but fortunately our society seems to be fairly well behaved in this type of activity so don't worry about it. Just carry out your normal pre-flight checks and go flying

[Shaunie]

On the downside our Txs are very low power and a wideband jammer could swamp our small signals with ease.

On the upside we usually fly in the middle of a field away from everybody. People could use a directional antenna from some distance away, the question is why would you want to? I know some people feel strongly about our hobby but they would also need to have the technical skills.

What about WiFi spectrum analysers, would they be sensitive enough?

IMHO, It's possible but I think the likelihood is small.

Shaunie.

[Former Member]

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[StarLoc FiveStar Adhesives]

The jammers sold for stopping phones, take down every phone near by, easily , completely illegal to do this as its so dangerous for emmergencys etc, they do take down rc systems but only close by due to power of them they have no range

The ones you usually get for sale a range of about 5 meters , cost about £40 to 60 , any more range than that and the cost is much higher

people use them to take down surveilence equipment and trackers etc in there cars and offices, but they are totaly illegal in the UK without a licence

Do a saerch for mobile jammer, hundreds of people sell them on lline 

Edited By StarLoc FiveStar Adhesives on 19/05/2014 14:44:48

[John F]

The items are intended for WiFi jamming at very short range, mainly for gimmicks but are also able to stop mobile phone signals. These claims are very wild and similar to the completely frenzied advice about LiPo's that some people offer, this has gone into urban myth territory.

Lots of tales of person walking down the street to set off every mobile phone he walks past etc. (obviously he can't as he has a jammer but doesn't stop the kids on the forums saying 'cool I want one' )

A lot of American sources argue that these are needed "With such state of things all connected housewares may become eyes and ears in your own house, serving as exposure of your privacy to the government." and fear of airbourne spies "Though most part of those robots are operated with the help of remote controls, so to be absolutely sure that no spy drone will be used for surveillance on your private meetings, business operations or any other events of your life, you need to use Remote Control Jammers."

Bonkers!

Some folk have properly experimented and produced a jamming signal to stop a Rx from getting inputs but they literally had to stand between the heli and the Tx to have any effect.

I think a lot of this is based on fear and over-reactions similar to the Bird Flu and Mad Cow disease scares and a lot of a " friend of a friend of a friend who saw this with his own eyes" tales.

Unless someone has a magic invisibility cloak and sneaks in unseen around you I don't think there is any need to worry.

Obviously the next person to see their aircraft nose dive for no reason are going to say "I know that was because of a 2.4ghz jammer!"

[GONZO]

You don't have to be near by. High gain directional aerials are readily available from the Bay. 26dB is approx 400x the input power in the beam, plus 4W amps are also available. Thus 100mW into a 4W amp gives 4W o/p. Put that into the high gain aerial, 4W x 400 = 1600W erp in the beam. But, lets turn it down a bit and say at least 1000W. Thats a good bit more than our 0.1W(100mW). Also, dont forget that full cert 'Hams' can use up to 400W in the first part of the 2.4gHz band.

[john stones 1 - Moderator]

Invisible man !!!!!!

Where ?

John

[John F]

Behind you!

[David...]

My Taranis uses ACCST (Advanced Continuous Channel Shifting Technology) and it is my opinion that the probability of jamming the whole band is low enough for me not to worry about this issue.

[Andy Ennis]

Funnily enough, I was browsing Gumtree the other day, and saw a Jammer for sale locally.

It was advertised with a 4W output, a range of 100 yards and capable of jamming from 2400mhz to 2500mhz.

I know nothing about all the different forms modern 2.4 radios use, but I would think this could interfere with a radio whatever sort of frequency hopping it uses (after all, if the whole band is swamped, I would assume there is nothing free to latch on to)

With a range of only a hundred yards, we probably wouldn't have to worry too much about someone in a car passing by when using one illegally, but it could be a concern if a club had a neighbour or somesuch that had a grudge (and there are plenty of clubs who have had trouble with a "nasty" person)

[GONZO]

You don't have to 'jam' the whole band. A strong enough signal, even outside the band, will probably 'block' the front end of an RC Rx as AFAIK they have little or no RF filtering/selectivity.

Yes, a grudge neighbour with this jammer and a directional aerial as in my previous post. Only the plane that it was aimed at would be affected and nothing else, leaving the pilot believing it was some sort of failure with his plane.

Or, as per a previous thread on this forum, someone using a power amp and a directional aerial to feed a signal to a remote location. Fly through the beam and ????.

The saving factor is that most flying sites are rural so all this is of little or no concern. More of a concern if the flying site is in an urban location.

Food for thought