Cell phones and RC signals?
02-01-2005, 08:57 PM
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Cell phones and RC signals?
Ok, maybe I should send my cell phone into the magazines and Futaba, JR, airtronics and all else who say they are fine. I have almost crashed twice, and have marvled myself watching the plane just go nuts on the ground in the pits each time my flying buddy calls me from 50 feet away. I have the GSM/digital phone from Cingular. My last GSM nokia did this as well. It makes the plane glitch super fast, but not a lot of travel, and not ever locking a control surface. Today the gal calls me, I feel it vibrate in my shirt pocket and I watch my Ultra Stick fly jittery and can hear the servos glitching in FLIGHT! I was landing when this happened fortunately. Anybody else have a take on this? It seems to be worse on my foamies with single conversion if that makes a difference... keith
02-01-2005, 09:15 PM
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RE: Cell phones and RC signals?
This has been addressed on several forums, I found it here on RCU as well as this link;
http://mbz.portage.net/cgi-bin/yabb/...num=1058287578
The problem exists with certain radios / chips, the quick solution - turn off ALL Cell Phone at the field. Hey - you didn't want to talk to them that bad anyway! If it really is important "They'll call back!"
http://mbz.portage.net/cgi-bin/yabb/...num=1058287578
The problem exists with certain radios / chips, the quick solution - turn off ALL Cell Phone at the field. Hey - you didn't want to talk to them that bad anyway! If it really is important "They'll call back!"
02-01-2005, 11:09 PM
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RE: Cell phones and RC signals?
Theres nothing wrong with cell phones wait for a while and you will find out.
This has been posted before and boy , you are in for it! Cell's Pagers and a bunch of sh@@# you won't believe![:@]
[8D]
This has been posted before and boy , you are in for it! Cell's Pagers and a bunch of sh@@# you won't believe![:@][8D]
02-02-2005, 07:38 AM
#5
RE: Cell phones and RC signals?
The RCM&E I got yesterday has a manufacturers bulletin from Multiplex that cell phones should not be used within 10' (feet for you outlaw
) of "programable radios". I was surprised when I read it and even commented to my wife about it.
) of "programable radios". I was surprised when I read it and even commented to my wife about it.
02-02-2005, 09:37 AM
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RE: Cell phones and RC signals?
The reason they delineate "programmed" radios is that the RF field emitted from a cell phone can indeed change the contents of stored memory if in close proximity. This phenomena is not unique to hobby radios but is true of any device that contains memory.
RF fields can cause loss of data. So that you can relate to this phenomena just imagine putting a piece of foil in a microwave oven. You'll see the power of a radiated field in the form of sparks jumping about on the foil. The cell phone, albeit lesser in power than a microwave oven, will similarly induce currents into you radio if in close proximity to it.
Just to pass some useful information along, most people don't realize that cell phones periodically transmit even when there's no incoming or outgoing calls.
RF fields can cause loss of data. So that you can relate to this phenomena just imagine putting a piece of foil in a microwave oven. You'll see the power of a radiated field in the form of sparks jumping about on the foil. The cell phone, albeit lesser in power than a microwave oven, will similarly induce currents into you radio if in close proximity to it.
Just to pass some useful information along, most people don't realize that cell phones periodically transmit even when there's no incoming or outgoing calls.
02-02-2005, 10:41 AM
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RE: Cell phones and RC signals?
Anybody want to fly in to my home town and go fly with me that says it wont make a difference is in for a real money loss. Bidding starts at a minimum of $1000. 
02-02-2005, 10:59 AM
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RE: Cell phones and RC signals?
No, I was doing a fuel run, and finally, after 25 minutes of cruise,touch and goes, and slow flight, it died. Ok, all is well.. coming in dead stick. Quiet, no wind, and I hear the phone ring and vibrate and I can hear the servos... Its a hollow wing, makes a lot of servo noise from the drone effect I guess. Whatever... Define close?
02-02-2005, 11:24 AM
#10
RE: Cell phones and RC signals?
I don't know about you guys because nearly everyone at my field has a cell phone and we've never had a problem. I have had mine ring while I was flying and one of my buddies took it off my belt, answered it and talked to my wife while standing right next to me. I am using a JR 8103 radio with both FM and PCM receivers from JR, Hitech and FMA and a Nokia phone. I happen to be on ham freqs, 50 MHz, but all the brands and freqs are represented and no one has complained. I also find it hard to believe that the big meets don't have cell phones all over the place from both contestants and spectators. This is not to mention PDAs surfing the web with wireless. Finally, the density of cell phones is much greater in Europe and Japan. Are they complaining about interference?
02-02-2005, 11:42 AM
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RE: Cell phones and RC signals?
Yeah, I dont know. But I do know it does ! The good news is, I dont see it as a threat to my plane or any others, it just makes a very fast glitch. Hardly noticable in flight. I just turn it off now.
02-02-2005, 01:43 PM
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RE: Cell phones and RC signals?
Hi!
I have heard Hitech flyers complain of this but being a JR flyer myself since the day one (1980) I have not encounterd it myself and neither have my fellow JR and Futaba fliers in my club. Only Hitech...[8D]
regards!
Jan K
Sweden
I have heard Hitech flyers complain of this but being a JR flyer myself since the day one (1980) I have not encounterd it myself and neither have my fellow JR and Futaba fliers in my club. Only Hitech...[8D]
regards!
Jan K
Sweden
02-02-2005, 04:54 PM
#14
RE: Cell phones and RC signals?
ORIGINAL: Dart373
No, I was doing a fuel run, and finally, after 25 minutes of cruise,touch and goes, and slow flight, it died. Ok, all is well.. coming in dead stick. Quiet, no wind, and I hear the phone ring and vibrate and I can hear the servos... Its a hollow wing, makes a lot of servo noise from the drone effect I guess. Whatever... Define close?
No, I was doing a fuel run, and finally, after 25 minutes of cruise,touch and goes, and slow flight, it died. Ok, all is well.. coming in dead stick. Quiet, no wind, and I hear the phone ring and vibrate and I can hear the servos... Its a hollow wing, makes a lot of servo noise from the drone effect I guess. Whatever... Define close?
02-02-2005, 04:57 PM
#15
RE: Cell phones and RC signals?
ORIGINAL: Dart373
My Futaba/ Futaba 9C combo glitches when its near the plane or radio.
My Futaba/ Futaba 9C combo glitches when its near the plane or radio.
Some radios do glitch if they are too close to the transmitter. We used to call it swamping the RX. I am not an expert on it but have seen it a lot. Never seen a phone affect one, but I am not saying it can't happen either. With electronics, anything can happen.
02-04-2005, 08:59 PM
#18
RE: Cell phones and RC signals?
The problem is not with swamping the reciever. That was pretty common in the dark ages of single channel and escapements and one frequency on 27.255 MHz.
The problem as has happened at our field has nothing to do with the effect on a reciever. We spend thousands of dollars doing RFI testing on our imbedded controllers where I work. Under some circumstances, the ringing of a cellular phone, or the transmitting of a signal, can wipe a computer radios volitile memory where you store your aircraft programs. The radio manufacturers could probably eliminate this problem, but your under $300 dollar computer radio would probably end up costing almost a thousand.
BTW, we used to take our products to a certified lab for RFI testing (It's a federal safety mandate). It used to take two days to a week to run tests and get data, at as much as a $1000/hr, plus engineer and technician time away from the office with attendant motel, restaurant, and travel costs. It sometimes took 5 or 6 trips to even refine the design to where we could take a prototype to the lab to try for final certification. We found a small screen room that fit our needs, used, for ONLY $175000, with basic equipment. ISO calibration of each of the three sensor probes used for measuring field strength runs $1200 and has to be done every two years. Now, we may only spend a day or two at the certification lab and usually get it on the first try. And our current products are much more complex, and harder to protect. One I am doing testing on right now has 5 different crystal frequencies and 6 different microprocessors. A single scan from our standard of 100 Hz to 8 GHz takes about 4 weeks of 8 to 10 hour days. One of our computer transmitters would probably take three or four hours to set up for a susceptability test and a couple days to run.
The problem as has happened at our field has nothing to do with the effect on a reciever. We spend thousands of dollars doing RFI testing on our imbedded controllers where I work. Under some circumstances, the ringing of a cellular phone, or the transmitting of a signal, can wipe a computer radios volitile memory where you store your aircraft programs. The radio manufacturers could probably eliminate this problem, but your under $300 dollar computer radio would probably end up costing almost a thousand.
BTW, we used to take our products to a certified lab for RFI testing (It's a federal safety mandate). It used to take two days to a week to run tests and get data, at as much as a $1000/hr, plus engineer and technician time away from the office with attendant motel, restaurant, and travel costs. It sometimes took 5 or 6 trips to even refine the design to where we could take a prototype to the lab to try for final certification. We found a small screen room that fit our needs, used, for ONLY $175000, with basic equipment. ISO calibration of each of the three sensor probes used for measuring field strength runs $1200 and has to be done every two years. Now, we may only spend a day or two at the certification lab and usually get it on the first try. And our current products are much more complex, and harder to protect. One I am doing testing on right now has 5 different crystal frequencies and 6 different microprocessors. A single scan from our standard of 100 Hz to 8 GHz takes about 4 weeks of 8 to 10 hour days. One of our computer transmitters would probably take three or four hours to set up for a susceptability test and a couple days to run.
02-04-2005, 09:23 PM
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RE: Cell phones and RC signals?
ORIGINAL: 50+AirYears
The problem is not with swamping the reciever. That was pretty common in the dark ages of single channel and escapements and one frequency on 27.255 MHz.
The problem as has happened at our field has nothing to do with the effect on a reciever. We spend thousands of dollars doing RFI testing on our imbedded controllers where I work. Under some circumstances, the ringing of a cellular phone, or the transmitting of a signal, can wipe a computer radios volitile memory where you store your aircraft programs. The radio manufacturers could probably eliminate this problem, but your under $300 dollar computer radio would probably end up costing almost a thousand.
BTW, we used to take our products to a certified lab for RFI testing (It's a federal safety mandate). It used to take two days to a week to run tests and get data, at as much as a $1000/hr, plus engineer and technician time away from the office with attendant motel, restaurant, and travel costs. It sometimes took 5 or 6 trips to even refine the design to where we could take a prototype to the lab to try for final certification. We found a small screen room that fit our needs, used, for ONLY $175000, with basic equipment. ISO calibration of each of the three sensor probes used for measuring field strength runs $1200 and has to be done every two years. Now, we may only spend a day or two at the certification lab and usually get it on the first try. And our current products are much more complex, and harder to protect. One I am doing testing on right now has 5 different crystal frequencies and 6 different microprocessors. A single scan from our standard of 100 Hz to 8 GHz takes about 4 weeks of 8 to 10 hour days. One of our computer transmitters would probably take three or four hours to set up for a susceptability test and a couple days to run.
The problem is not with swamping the reciever. That was pretty common in the dark ages of single channel and escapements and one frequency on 27.255 MHz.
The problem as has happened at our field has nothing to do with the effect on a reciever. We spend thousands of dollars doing RFI testing on our imbedded controllers where I work. Under some circumstances, the ringing of a cellular phone, or the transmitting of a signal, can wipe a computer radios volitile memory where you store your aircraft programs. The radio manufacturers could probably eliminate this problem, but your under $300 dollar computer radio would probably end up costing almost a thousand.
BTW, we used to take our products to a certified lab for RFI testing (It's a federal safety mandate). It used to take two days to a week to run tests and get data, at as much as a $1000/hr, plus engineer and technician time away from the office with attendant motel, restaurant, and travel costs. It sometimes took 5 or 6 trips to even refine the design to where we could take a prototype to the lab to try for final certification. We found a small screen room that fit our needs, used, for ONLY $175000, with basic equipment. ISO calibration of each of the three sensor probes used for measuring field strength runs $1200 and has to be done every two years. Now, we may only spend a day or two at the certification lab and usually get it on the first try. And our current products are much more complex, and harder to protect. One I am doing testing on right now has 5 different crystal frequencies and 6 different microprocessors. A single scan from our standard of 100 Hz to 8 GHz takes about 4 weeks of 8 to 10 hour days. One of our computer transmitters would probably take three or four hours to set up for a susceptability test and a couple days to run.
You're wasting your breath, err, finger movements! I explained this anomaly numerous times in these forums but it simply isn't understood....few understand what we're talking about.
It's a curious quirk in life that appliances that are familiar to the masses instills a false notion to them that they actually understand what's happening when using the appliance. Few understand, or have ever heard of radiated rfi/emi.
Do your own search on this subject in these forums and you'll see that those of our ilk are shouted down by a few that use these appliances and have by virtue of using them declared themselves "electronics experts".......
Can of worms? Yep!
02-04-2005, 09:24 PM
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RE: Cell phones and RC signals?
It is hard to put the lid back on a can of worms
Cheers.
