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[blowdown]

Has anyone experienced interference from aircraft transmissions to their 2.4 model radio control equipment or was it a trick of the imagination whilst sailing my 1 metre yacht today on Lake Windermere. Was sailing steadily on a reach when a Hercules transport plane appeared flying directly up the lake at about 150 feet height and passed directly over the boat. An impressive sight but my boat turned and sailed directly away from me out of control. Control was regained after about 20 secs just about at the limit of the transmitter range. It may be significant that the Eurofighters use this same flight path but at about 650 m.p.h. roughly every hour without any effect on the radio equipment. Do we have to get early warning of the approach of a Hirkibird ?

                                                             From blowdown.

[dodgy geezer]

There would be quite a wind hitting the lake surface for quite some time after a Herc passed at that height - could this have had an effect?

[blowdown]

Thanks dodgygeezer for your response. We thought of this but the two other boats rounding the mark in close proximity were not affected. They were using steam radio rather than 2.4 which made me wonder if the older planes use a type of radar which affects the 2.4 gear, in which case it would be wise to avoid areas giving air displays. Could this be a shortcoming of a very succesful and convenient piece of equipment.         

[dodgy geezer]

What radio were you using?

My understanding of the 2.4Ghz protocols is that other transmissions shouldn't affect them unless the whole band is swamped. And if the plane was swamping the 2.4Ghz band, it would be causing a lot more than interference to R/C - everyone's computer networks would be going down, including shops and offices. I can't see the RAF being that popular if this was a standard feature of their aircraft.

Of course it's possible that they were testing some kind of jammer, or using a ground sweeping radar of some kind.... I wonder if it's worth sending a letter to the commander of the local air base, explaining the problem and asking it it might be them...? 

[Colin Bishop]

When it comes to the Military, anything is possible. When I had my own boat it was generally acknowledged that GPS was unreliable in Portsmouth Harbour due to the naval radars!

Colin

[malcolmfrary]

Just found this

http://www.bbc.co.uk/news/uk-scotland-highlands-islands-17574089

Mostly about GPS being jammed, but the last line reads "Comhairle nan Eilean Siar said jamming had also been blamed for affecting internet connectivity and mobile phone and satellite TV."  And, of course, internet wireless broadband largely runs in the 2.4GHz band, so its not a big leap to assume that the military have toys that produce swamping interference.

[AlisterL]

Bruce @ RCModelReviews.com has done some work testing various 2.4GHz systems and this covers how interference can cause problems with 2.4GHz signals.
Two of the interesting articles are:
http://rcmodelreviews.com/spreadspectrumtests.shtml and
http://rcmodelreviews.com/dx8dsmxreview.shtml

The latter is interesting as it has the links to previous tests of DSM2 equipment.

I'm neither endorsing or condoning any type of equipment, not can I speak to the integrity of the tests, but lets just say it's interesting what is shown...

[dodgy geezer]

It looks from this as if a 2.4Ghz FH system is pretty immune to any radio interference (unless it's a jamming signal specifically designed to impact the 2.4Ghz band).

If that's the case it's probably worth informing the powers-that-be (military or the Home Office Radio Regulatory people) about a possible impact. If the military want to jam signals they will need to do a risk analysis and inform users of the band, and if no one realises that models use it they could easily be forgotten. As was mentioned earlier, model aircraft giving a display at an air show might be a particular danger...

[Netleyned]

I would not have thought that military aircraft at an air show would be operating ECM

Ned

[dodgy geezer]

On second thoughts, you are right - probably not. More possible over some range or test facility. Of course, these are often in remote areas, and a simple risk analysis might suggest that it's reasonably OK to disrupt GPS or mobile phones in these places for a short period of, say, 30 seconds. But if there happens to be a model flying club there, and they are flying jets because this remote area is nice and safe, it could be a bit of a problem.

It still seems a good idea to me to make the Military/Radio Regulatory people aware that this might be an issue...