Matt Carlton Posted April 17, 2022 Share Posted April 17, 2022 Hello, After a couple of flights where I seemed to suffer a bit of interference, I wondered if the number of mobile devices in various pockets might be affecting things. Bluetooth, I believe, works on 2.4Ghz, and although range is limited, ones own pocket or even car is usually quite near the tx! Possible? Obvious solution is to leave BT off when flying, but still. Ditto data transmission and satellite guidance for agricultural vehicles? Not BT obviously but a potential cause of issues? Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted April 17, 2022 Share Posted April 17, 2022 Leave mobiles back in the pits / car? BMFA News, Manny’s musing referenced this very thing. 1 Quote Link to comment Share on other sites More sharing options...
Graeme White Posted April 17, 2022 Share Posted April 17, 2022 Our fields rules are phone in the car park, not in pits or flight box unless for safety if flying solo etc Quote Link to comment Share on other sites More sharing options...
Matt Carlton Posted April 17, 2022 Author Share Posted April 17, 2022 Generally we do leave the phones in the car, but with the number of devices using BT, I was just wondering. I hadn't read the Manny's Musing bit, I'll dig it out. With the frequency getting more and more congested, maybe its time to go back to 35 ? Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted April 17, 2022 Share Posted April 17, 2022 It would need someone on here who is really clued up on rf data protocols to give an informed opinion on this. I believe, as said, Bluetooth uses a 2.4Ghz band, but probably a totally different protocol to our sets. I think the latest FrSky txs use Bluetooth for the wireless trainer link, which suggests it doesn't cause issues with the model rf link? Quote Link to comment Share on other sites More sharing options...
Trevor Posted April 17, 2022 Share Posted April 17, 2022 FWIW, the incident which prompted Manny's article concerned a transmitter apparently changing modulation methods in mid flight. Coincidentally or not, the pilot's phone (in his pocket) received a text message just before the model went out of control. I'm all for taking precautions, but I think it's important to be clear that, in this case at least, the issue seems to have been the electromagnetic susceptibility of the transmitter's digital circuitry rather than interference with its 2.4Ghz transmission. 1 1 Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 17, 2022 Share Posted April 17, 2022 You can also buy bluetooth units that go in your Tx and transmit telemetry to your phone. Multiplex also do a bluetooth dongle that plugs into their Wingstabi Receivers to allow you to program them from your phone. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted April 17, 2022 Share Posted April 17, 2022 I use the BT buddy system with my FrSky TXs and, to date, there have been no issues. I tend to leave my mobile back in the pits but I do not take off my Apple Watch! Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted April 17, 2022 Share Posted April 17, 2022 2.4ghz was adopted by the military to operate in crowded environments, and may frequency hop or other to maintain a signal. Just look at the flightline at a model show with 10 and 20 pilots in the air at one time, and countless hundreds of onlookers with phones in their pockets, just feet away. The airwaves are more crowded then ever, but 2.4ghz does its magic operating sucessfully. We give it the best chance we can, by charging battery packs, having a frequent voltage check routine, and fitting and aligning aerials and antenna as best we can. Drop outs and fades will occur, but the equipment 're-acquires in milliseconds. Installation and adequate power are key. 5 Quote Link to comment Share on other sites More sharing options...
john davidson 1 Posted April 17, 2022 Share Posted April 17, 2022 On a some what related issue, my Nissan has forward radar for emergency braking, at a T junction 100 metres from my house it 9times out of ten must pick up a signal and goes out of service. If I want it back I must stop and switch off to reboot, which is a bit annoying. Is this Bluetooth related does anyone know? Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted April 17, 2022 Share Posted April 17, 2022 I don't believe it, being British on a French field I actually answered my phone once and did rolling circles at the same time, yes I can be a p,,,,,? Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted April 17, 2022 Share Posted April 17, 2022 Just now, Paul De Tourtoulon said: I don't believe it, being British on a French field I actually answered my phone once and did rolling circles at the same time, yes I can be a p,,,,,? Ps you can't do that on mode 1? Quote Link to comment Share on other sites More sharing options...
John Minchell Posted April 26, 2022 Share Posted April 26, 2022 You can if you're on hands free with an earpiece! Quote Link to comment Share on other sites More sharing options...
Paul De Tourtoulon Posted April 27, 2022 Share Posted April 27, 2022 7 hours ago, John Minchell said: You can if you're on hands free with an earpiece! Yes so you can talk to yourself and make people think that you are on the phone,,,? Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted April 27, 2022 Share Posted April 27, 2022 All of the advanced 2.4 GHz systems (Bluetooth, Zigbee, Spread Spectrum, etc) are designed to be almost totally immune to interference. Yes, ultimately you will reach a point where the signal is totally overwhelmed and control is lost, but until you get very close to that point, you will be totally unaware. The rate of data transmission is so high on modern RC systems, that even if half the "packets" are lost, you are unlikely to notice any difference. The much more likely scenario is the RF bursts from a mobile phone breaking directly into the transmitter circuits. I'm sure you've all heard interference from a mobile phone on a HiFi system, or transistor radio, or even a wired intercom when a phone is close. A mobile phone can send out quite powerful, short duration bursts of RF that will break directly into poorly screened electronics. Most modern RC is pretty thoroughly screened anyway, as to meet CE and FCC standards, they are not permitted to radiate spurious signals from their own internal electronics. This works both ways, and makes them less susceptible to external RF breaking into them as well. Some older transmitters may not be as well screened against this kind of breakthrough. I am aware of one popular brand from a few years ago that seemed to be quite susceptible to this. Most current systems seem to be pretty bomb-proof on this front. The best screening is to use a metal cased transmitter - as in days of yore! However, nearly all current systems use some kind of plastic for the case - prettier and cheaper, but not nearly as good for the purpose! Usually the plastic contains some kind of conductive material, or has a conductive layer on the inside, to make it act as a Faraday Cage: https://en.wikipedia.org/wiki/Faraday_cage (Yay! Bring back vinyl clad aluminium transmitters! ? ) Most modern radios are remarkably immune to the interference from mobile phones. If they were not, we would be hearing about far more than the odd isolated incident... -- Pete 1 1 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted April 27, 2022 Share Posted April 27, 2022 21 minutes ago, Peter Christy said: Most modern radios are remarkably immune to the interference from mobile phones. If they were not, we would be hearing about far more than the odd isolated incident... Back on topic and a very informative post Peter. ? Quote Link to comment Share on other sites More sharing options...
John Lee Posted April 27, 2022 Share Posted April 27, 2022 Agree with Peter. I use a Bluetooth dongle plugged into my Tx to feed telemetry, in particular vario tones, into wireless bud earphones so as not to annoy my fellow flyers with constant beeps etc. The Bluetooth module (from Amazon) can be seen in the bottom left of the photo. Jeti telemetry includes 'Q' which monitors the signal quality (packets dropped) on the round trip Tx>Rx>Tx. The addition of the Bluetooth module & Bluetooth earpieces does not produce any measurable drop in the 'Q' and I have been using it for a couple of years flying 3metre gliders at the limit of my eyesight. The DS-24 Tx does have a full metal faraday cage case but I also have a DS-12 Tx which is plastic cased and again the module/earpiece works on that without any issue. Quote Link to comment Share on other sites More sharing options...
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