Do Cell Phones Really Interfere with RC Radios?
C Fossa
My guess as an electrical engineer conducting research in the wireless
communications field would be no ... but I have no hard data to back this
up. It seems that a recent thread on this topic has degenerated into a
discussion on whether or not we really "need" cell phones. I'd like to hear
from anyone with actual data on this issue. FWIW here are my thoughts about
cell phones and RC radios:
1. The frequency bands are not even close. In the US 1st generation
(analog) cell phones operate in the 800-900 MHz range. 2d generation
(TDMA/CDMA digital) cell phones operate in the 1800-1900 MHz range. GSM
phones in Europe are in similar frequency bands. This is not to say that
there can be no interference across bands. Intermodulation (harmonic)
frequencies can be generated by cell phone(s) ... but the power would be
really low for IM signals as far away as 72 MHz. There could also be some
"close-in" effects of placing the two antennas right next to each other.
Again, the cell phone Tx power is <0.5 or 1.0 Watts so even close in this is
low. Placing a cell phone Tx next to an RC Rx might cause more problems than
having the phone next to a Tx. The relatively strong cell phone Tx signal
could "drown-out" a weak RC signal at the receiver ... so don't accidentally
leave your cell phone inside your plane :-)
2. There is a bunch of "signaling" that goes on for cell phones. This
includes things like signals from the phone searching for a base station,
pages from the base station to "wake-up" a phone, ringing signals, hand-offs
between base stations etc. These operate differently from the actual phone
call and could cause different problems.
3. Modern cell phones do vary their transmit power based on signals from the
base station. This prevents phones close in to the base station from
swamping out those far away. It does not allow phones to transmit above the
allowed levels of about 1 W. Base stations do have higher power .. but it
is effectively split up between the mobile phones it is talking to. Not all
(if it is 20 W) will be transmitted to one guy.
4. The idea that a cell phone can re-program a digital RC radio is really
interesting to me. I guess this could happen if the signal was strong
enough and it was somehow picked up by unshielded wires in the Tx acting
like antennas. I'd really like to see this in person.
Anyway, I think this is an interesting and valid topic. I personally do not
think there is any risk using cell phones near RC radios. But, as I said at
the beginning of this rant I have no hard data to support this point of
view. If you do have some data on this please share it with the rest of us!
Also speak up if you disagree with my view on cell phones.
Also, if I was using a cell phone at the field I'd be more concerned with
what it is doing to my head than what it is doing to my plane :-) Like your
RC transmitter, cell phone antennas are omni-directional and transmit power
in a "donut" shape with the antenna through the hole of the donut. Hold
your phone to your head, and at least 30% of the transmitted power is being
absorbed by your head. There have been a bunch of studies on this, but no
conclusive answers either way. "Hands-free" devices are starting to become
popular and they reduce the energy absorbed by your melon. You make the
call (pun intended) on that one.
Carl
D SHANNON
you are asking if they interfere and not if they are canceling out like
would be the case if on the same freq. I have seen 3 cases and was prven.
AMA also has documented on the intereference if worn by the pilot and in
close proximity to the TX.
enough said.
"C Fossa" <cfossa...@cablenet-VA.com> wrote in message
news:a4sdv...@enews1.newsguy.com...
spam me_2hinton@attbi.com Charlie
and do not really see how a cell phone could shoot down a plane, however
without doing a series of experiments i would not rule it out as a
possibility
if someone has actually documented cell phone, pager, garage door opener,
keyless car lock interfering with the 72mhz rc airplane band in a real world
setting please post the details
regards
charlie
starcad
anything from the AMA reguarding cell phone usage either on the pilot or in
the pits. This thread is not about interferance but about reprograming the
micro-proccessor in the transmitter. In my early days of computer
programing you had to shine an infared light on an eprom window fo several
minutes to erase the eprom. I'm not 100% certin but it seems to me that the
low power of a cell phone would not erase the memory of a modern computer
radio.
Please share with myself and the rest of the group the three proven cases
where a cell caused interference with a model aircraft as I and many, many
others in this group would like that information. Why do I want it?
Because I like others wear a cell phone when I'm flying (work) and many
others in my club do the same. If there is a problem I would like to be
able to share it with my club members to prevernt a possible accident from
happening.
D SHANNON <airp...@grm.net> wrote in message
news:a4sh6p$5lb$1...@ins22.netins.net...
Dave Stadt
D SHANNON <airp...@grm.net> wrote in message
news:a4sh6p$5lb$1...@ins22.netins.net...
> to answer shortly on "DO THEY INTERFERE" yes not all the time but yes .
> you are asking if they interfere and not if they are canceling out like
> would be the case if on the same freq. I have seen 3 cases and was prven.
Care to give the details and the method used to prove the interference.
Dave Stadt
To add to your question why would a cell phone re-program the
micro-processor but the transmitter and digital circuitry that is part of
the RC transmitter would not. Nor does the transmitter of the guy standing
next to you which is on almost the same frequency as yours cause a problem.
Sounds like urban legend to me. No one has provided proof. Some have gone
so far as to invented electronic theories to support their positions. There
are thousands of cases where transmitters of hundreds of watts output and
microprocessors are operated in close proximity without any problem. If
someone wants an example go look at a police car or an airplane.
starcad <sta...@mindspring.com> wrote in message
news:a4sll5$gr7$1...@slb0.atl.mindspring.net...
D SHANNON
flying......upon takoff when the plane came into exactly across from us on
the runway it went crazy all servos jerking and the plane was just breaking
ground.. this caused to plane to take a dive and terminated this takeoff..
when we walked up to the plane all servos were going crazy and the student
still had the tx in his hand... I out of curiousity asked him to shut his
phone off and when he did the servos quieted down and were calm. turned
phone back on and same thing....... he passed the tx to me I walked a few
feet away and was fine.. seemed that when the phne and tx were close it was
somehow interfering with the output of the tx. this was a plain ol 4 channel
futaba and a nokia 5100 series phone. another incident happened another
day with same basic story as the first.... then the third was a pilot just
taking off and his spotter was wearing a phone now this one we can not
totally prove it was the phone but it was the crash that implemented our
rule.
as far as the info from AMA , I attained this when talking with them on us
having to look for another field, I called to inquire about being along the
interstate as I know from experience that a lot of truckers run High powered
CB's ... I know this is illegal but i know of 4 people who can do this to a
cb by doing nothing more that opening the case and hooking up to a RF meter
and crank it up , then by soldering in a jumper can increase the modulation
to 135% ... this will make a cb capable of transmitting over 30 miles as I
have done it and is clear as can be. there is also alot of them running on
channels below 1 and above 40 .. I am still trying to locate my channel
chart that is given after this "upgrade" when I do I will post the exact
freq that is being trans on when doing this. anyhow when I inquired I was
informed of the cell phone usage, and directed to Wess Decou to discuss
further with him.. he never returned my call.
oh I found the paper on the channels some of the freq being trans on are the
26, 27, 28,29
and I do believe this thread was also talking of the interference I was
referencing as well.
"starcad" <sta...@mindspring.com> wrote in message
news:a4sll5$gr7$1...@slb0.atl.mindspring.net...
Ray Haddad
wrote:
>Again, D, I ask you where your getting your information as I have yet to see
>anything from the AMA reguarding cell phone usage either on the pilot or in
>the pits. This thread is not about interferance but about reprograming the
>micro-proccessor in the transmitter. In my early days of computer
>programing you had to shine an infared light on an eprom window fo several
>minutes to erase the eprom. I'm not 100% certin but it seems to me that the
>low power of a cell phone would not erase the memory of a modern computer
>radio.
Don't take this as a put down, because it's not. The light source was
Ultraviolet, not Infrared. That's an easy enough mistake to make.
>Please share with myself and the rest of the group the three proven cases
>where a cell caused interference with a model aircraft as I and many, many
>others in this group would like that information. Why do I want it?
>Because I like others wear a cell phone when I'm flying (work) and many
>others in my club do the same. If there is a problem I would like to be
>able to share it with my club members to prevernt a possible accident from
>happening.
I also don't know of any condition other than a reset to the
microcontroller of the receiver that will cause any reprogramming to
occur. To make that happen would require that you turn the receiver on
from dead off and hold a digital line low on the EEPROM at the same
time as sending a very specfic set of instructions in the exact
correct order to the EEPROM that will reset it. The likelyhood of that
happening? Probably one in a trillion or higher.
As to proven cases, here's one you can try yourself easily enough. Put
your mobile phone on top of one of your airplanes. Leave the
transmitter on or off, your choice. Call your mobile from your home
phone and just before it rings and after the first ring, watch the
servos. If they are like every plane and receive I tested recently,
they will glitch once before the first ring and one time afterwards.
Otherwise, there is no effect.
I am an electronics engineer by training and am now retired from that
line of work. I worked extensively in design of keypad interfaces for
Phillips/Sony in 1995, 1996 and 1997. The digital signal paths are
critical and they are the cause of most of the extraneous noise
generated by cellular phones.
The other thing is the IF or intermediate frequency stages which can,
on rare occasion, cause problems in receivers. The more sensetive the
receiver, the worse the problem is. To demonstrate this, take any two
portable AM or FM radios and place them near each other while they are
playing the same or any other station. You will clearly hear buzzing
from one or both of them because of the IF stages drifting and
detuning. This is caused by the coils in each IF stage stealing a bit
of the 455khz signal from the other radio and beaming a bit back
simultaneously.
With all of that being true, I still find no real reason not to use a
mobile phone in the pits or on the flight line. Distances over 1 meter
were enough to keep any interference from causing problems. I tested
two different types of mobile phone recently with the only glitch
coming as I described above.
There is one condition I didn't test for and that was when the phone
was being used to play a game. The microprocessor is heavily involved
in that mode and would likely cause some glitches when played near a
receiver.
It is absolutely correct to say that the fundamental frequencies of
the mobile phones (2 to 2.5ghz) and model aircraft (29 - 75mhz) share
no common harmonics above 3db and are safe to use near each other.
Naturally, a strong enough signal from either can mask any other RF
but that would required at least a bigawatt (joke here) of power. I'm
not sure how much power, just lots more than any cell phone or RC
transmitter can emit without an external amplifier. The way that works
is for all diode junctions to be swamped as they decode RF from
circuits overdriven with RF for which they are not normally tuned.
Unfortunately, the problems with any interference don't come from the
fundamental frequencies of either device but from a most unlikely but
unsurprising source. They occur because of the commonality they have
with microprocessor circuits.
Ray
The Natural Philosopher
Dave Stadt wrote:
>
> To add to your question why would a cell phone re-program the
> micro-processor but the transmitter and digital circuitry that is part of
> the RC transmitter would not.
Right. It *is* possible. Not likely, but possible.
Flash memory - the sort of thing that holds its state even when switched
off - depends on tiny charges being stored for a very long time - its a
bit like a lot of tiny Nicads in silicon to hold the programming.
Normally, it works the way its intended to, and holds its state until
specific conditions are applied to teh circuits to make them change.
BUT situations where extremely high field strengths are involved, can
cause flash memory to erase itself. There is no doubt that a high power
RF field can do this. It can also effect tge operation of any
ewlectronics, by inducing currents in teh circuitry that they are not
desiggned for. The lower power the circuitry themore prone it is to this
effect. Flash RAM is (almost) zero power in normal operation....
Why doesn't eh TX itself do this? Because teh manufactureres make sure
that it isn't doing enough close enough....but that is *not* the same as
having a mobile phone antenna less than an inch from the flash RAM. Also
teh frequencies (900 or 1900 MHz, depeninding on USA/Europe/Style of
phone service) are much higher, and the chance of resonance in the TX
PCB increasing the signals to dangerous levels is far more than at 27,
35 or 72Mhz.
As to wehehr it does actally happen? I would guess that once in a blue
moon, with a phone in a breast pocket and the tranny clutched tight to
it, it might.
So if you are into seripous safety and fly big fast models, leave the
thing in teh car.
If you are a sport flyer who can take their eyes off the model for tens
seconds while you asnwer the call from your broker in time to sell Enron
short and make a million....well its up to you.
Personally, I have run my futaba and 1800Mhz phone in close proximity
many many times with no ill effect.
But my local club is strict and insists that I do not carry the phone
onto the flying field, and when I fly there, I respect their position.
Chris Dugan
My local has a problem with a mobile phone mast sat right next to the field,
they have even documented proof of interference and had to move the flight
line to the other end of the field (and put restrictions on the flying
area). Me I don't fly there any more as the risk to myself/people and my
aircraft/heli's is too much to risk. I have now found an alternative club,
and all because of blóódy Vodaphone.
One thing about the relative strengths of a cellphone and r/c TX is to
remember that an r/c TX puts out about 100mW which is 5 to 10 times less
than the power put out by a cellphone. So all this argument for using cell
phones at the flight line is just asking for trouble its going to get
swamped by the signal of a cellphone
We have an obligation to fly in a safe and responsible manner at all times,
please everybody remember that is the primary rule of all flight model and
fullsize.
Don't risk trying anything stupid such as cellphones at the field for
exactly the same reasons that you would carry out a range check and
mechanical/airworthyness check before each flight.
--
Chris (UK)
Remove the "nospam." from reply address to reply
Kurt Dorsey
at home (I use it for all long distance calls) using my hands free set
and I was working on my plane during this. I flipped on the RX and
anytime I waved my cell phone around near the RX the servos
fluttered... it would happen anytime I was within 6 or so inches of
the RX or the TX. I have a Futaba 6XA TX. Yet at my feild I see
people on there Cell phones in the pit all the time and I am unaware
of any crashes that were related. So I guess unless I were to put my
Cell inside my plane there probably wouldnt be any problems...
Kurt
"D SHANNON" <airp...@grm.net> wrote in message news:<a4ssok$j8j$1...@ins22.netins.net>...
starcad
Ray Haddad <rha...@iexpress.net.au> wrote in message
news:ibv37ugvbq947u74r...@4ax.com...
> On Mon, 18 Feb 2002 21:48:45 -0700, "starcad" <sta...@mindspring.com>
>.
>
> Don't take this as a put down, because it's not. The light source was
> Ultraviolet, not Infrared. That's an easy enough mistake to make.
> Ray
Mavric
its sound and start playing the nearest radio station! That thing will not
come any where near my plane.
Justin Behr
"C Fossa" <cfossa...@cablenet-VA.com> wrote in message
news:a4sdv...@enews1.newsguy.com...
Henry
other antenna picking up that extra power 8^.
-- Snip --
Also, if I was using a cell phone at the field I'd be more concerned with
what it is doing to my head than what it is doing to my plane :-) Like
your RC transmitter, cell phone antennas are omni-directional and
transmit power in a "donut" shape with the antenna through the hole of
the donut. Hold your phone to your head, and at least 30% of the
transmitted power is being absorbed by your head. There have been a
bunch of studies on this, but no conclusive answers either way. "Hands-
free" devices are starting to become popular and they reduce the energy
absorbed by your melon. You make the call (pun intended) on that one.
-- Snip --
Jimmy Huang
On Tue, 19 Feb 2002 05:13:51 GMT, "Dave Stadt" <dhs...@ameritech.net>
wrote:
> There
>are thousands of cases where transmitters of hundreds of watts output and
>microprocessors are operated in close proximity without any problem. If
>someone wants an example go look at a police car or an airplane.
Dave,
A Police Car and an airplane would be a BAD example. If I recall
correctly, when they first started installing those computers into the
police cars, they had *all* sorts of problems, as the radio would
interfere with the computer, and vice versa. It took some engineering
to make that work right.
As for the airplane, there has been 2 documented cases where a cell
phone caused the airplanes navigational system to go off the deep end,
and the plane flew miles and miles off course. Even today, when you
get on an airplane, first thing the pilot tells you to do, turn off
all "electronic gadgets" if you want to survive this flight. Think
about that!
RC manufacturers spend far less money and time trying to track
interference down (as compared to FAA and Police Car engineers). I
don't doubt for a second there are some strange interactions between
certain combinations of cell phones and Transmitters or Receivers.
I just wish D SHANNON could have been more specific about the cases he
has witnessed. Transmitter Model/Make transmit mode, FM/AM/PPM/PCM?
Receiver Model/Make. Cell phone model/make and technology used, main
frequency. Channel of RC Transmitter, etc.
I personally think a policy wide ban on cell-phone(s) in pitts area or
flight line is too ridiculous as the problem is probably very specific
to Transmitter/Rx/Channel/Cell-phone model combos. It probably makes
more sense to figure out what's acting up and getting the manufacturer
to FIX it, as they have done with the police cars.
Jimmy
starcad
details, type of phone, distance from T.V. etc. I really think we'ed all
like to get a better understanding of this.
Mavric <be...@tznet.com> wrote in message
news:oUyc8.111199$d34.8...@bin8.nnrp.aus1.giganews.com...
starcad
get him to provide the very thing your asking for - specifics. I did not
want to push him any farther as I don't want to upset him thinking that I'm
trying to provoke a response. D, that is not the case. I think your right
on the money Jimmy and we all really need to find out if something is really
happening and causing interference or reprogramming of our radios. Here is
what I do know. Manufactures are building cheaper and cheaper equipment.
My Question is are they using cheaper components and thus causing greater
amounts of interference?
Jimmy Huang <jimm...@kuentos.guam.net> wrote in message
news:68o57ukv8jpebp5p3...@4ax.com...
The Natural Philosopher
Kurt Dorsey wrote:
>
> I too have had this same sort of thing happen. I was on my cell phone
> at home (I use it for all long distance calls) using my hands free set
> and I was working on my plane during this. I flipped on the RX and
> anytime I waved my cell phone around near the RX the servos
> fluttered...
Did you have the TX on?
RX's are sensitive to interference when not recieving a valid signal
WasdenDon
problems. Our transmitters and receivers are on 72 mega hertz. Old mobile
telephone and pagers were on 150 mhz. Cellular phones are on 800 and 900 mhz.
No chance for interference. Our field is within 1/4 mile of a cell site and we
never have a problem. It's called frequency separation.
PDW
D SHANNON
"WasdenDon" <wasd...@aol.com> wrote in message
news:20020219195514...@mb-cf.aol.com...
D SHANNON
5135 and Tx on 38 FM... the recver would be a common one that would come
with such a Futaba set up.... no one is going to make me upset... the mind
doesnt always remember to include all such things, and if you dont ask I
dont know.... hope this helped... cause I too would like to know if there is
a specific trend or not... as the third instance was also a Futaba Attack
4chnl FM on 50 but all I know on that recver is it was a wideband .. which
shouldnt have been used in the first place... but the CELL I dont know what
it was.. I will ask the guy and see if he can tell me. now dont get me wrong
here but all instances were involving a Futaba radio .. not to say that any
other brand is immune. Dell
"Jimmy Huang" <jimm...@kuentos.guam.net> wrote in message
news:68o57ukv8jpebp5p3...@4ax.com...
>
Fritz the Cat
interference:
Futaba 8UHP with CAMPAC
Erickson flip phone
US Models so 72Mhz Tx and Cingular carrier on the Cell.
I had several models programmed including a V tail glider on PPM and a
Heli on PCM in the Tx main EEPROM memory. Everything was fine for
over a year. Then I got the Cell phone. During trips to the field I
tucked the activated phone next to the TX in my fieldbox. After a
couple of trips I noticed one servo on the V tail setting had reversed
itself. The glider was flow several times in the preceeding weeks and
no programming changes were done. The backup program in the CAMPAC
was correct. After a few more trips one of the PMIXes in the Heli
program INHibited itself. Again model was previously flown, no
program was changed and the CAMPAC backup was correct. Both changes
take a bunch of button presses to change and I did not open either
program because I already had then tuned months previously.
I read a note on the newsgroup about interference from cellphones and
data changes in a 8U so I made sure the cellphone never got nearer
than 3 ft to the Tx after the second incident. For the last couple of
years no other resets/changes occured with the original phone, Nokia
replacement and now Sprint PCS.
Actual event - draw your own conclusions - I'm sayin' nothin'.
Fritz
Chris Dugan
can but I don't have money to burn and I think that people who take their
phone with them and try their luck are going to get bitten one day.
There is ALLWAYS a risk of interference if there is another RF source
nearby, or even if there is a large metal structure nearby.
At home I can get interference on the cable TV signal from my 35Mhz and
27Mhz gear but not 40Mhz gear, so I say bollocks to those who say "the
frequencies are different ... then there's no way they can interfere". That
may be true in an ideal world but not this one.
--
Chris
steve
"Chris Dugan" <cdu...@nospam.ntlworld.com> wrote:
Not sure whether anyone posted this in this thread, but I took this from the
futabarc website:
<quote>
Is there any risk to using cellular phones in close proximity with my radio?
There are two separate parts to this question -- frequency transmission
interference vs. computer processor interference.
FREQUENCY: While most fields do not recommend the use of cell phones for
liability reasons, there should never be a frequency problem between cell
phones and radio systems. The FCC makes sure that neither cell phones, nor
R/C frequencies are close enough in range to interfere with each other and
they enforce this policy actively. We have many fliers in high cell phone
use areas, who have never encountered frequency problems related to cell
phones, but once again, with the volume of cell phones today, and for safety
sake, it is best not to fly during a large amount of cell phone use in the
area of the flying field.
PROCESSOR: There have been a few reported cases of modelers seeming to
encounter strange programming issues with their computer radios when used in
the vicinity of an operating cell phone. We have never seen this nor can we
replicate it; however, when it comes to safety we always recommend the
modeler err on the side of caution and avoid use of your radio equipment in
close proximity with a cellular phone which is turned on.
It is always best to take all possible precautions to avoid a situation that
could potentially harm someone. Therefore, we recommend limiting the
proximity of powered-on cellular phones to at least 1000 feet from any radio
in operation.
</quote>
The url (for anyone interested) is
http://www.futabarc.com/faq/product-faq.html#q278
Steve
---
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Mark
missing the problem. The power from a mobile phone is capable of doing a fair
amount of damage. It is not so much a case of interference with the RC
transmitted signal as much as it is to do with electromagnetic interference
directly at component level on the circuit board inside the transmitter. Modern
RC's have microprocessors inside which themselves can be "crashed" by external
RF signals. A micro crashing tends to "jump" to an undetermined point in it's
program. The amount of power required to acheive this could be quite small and
is directly related to the design of the equipment and the exact position of
the mobile phone relative to the RC radio. The effects or RF energy are curious
to say the least and are too complex to go into too far here, but in short,
without very careful consideration at the design stage, anything is possible,
and with most RC equipment being packaged in plastic cases caution is very
definately advised.
Where code changes have been observed, it is likely that the microprocessor has
crashed and done a "jump" of execution to a random location. This could easily
execute the code to save info to the non-volatile memory where the saved data
exists. If the "save" code is executed without being set up correctly, it is
likely that it will write random data to a random location in the memory block.
The result of this as far as the RC is concerned is that settings which are
stored can suddenly change .... any setting, to any value... . Whilst every
effort is made for the transmitter micro to recover from a crash, once a
setting has been altered it will stay altered.
The other side effect could be during flight where the micro is interpreting
control signals etc, if it crashes, it will send random control signals to the
RX and again although the control micro will be designed to recover from this,
your airplane may not be in a location or attitude to do the same.
I know this will probably pose more questions than answers but as I said
before, just be careful with mobile phones etc..
The Natural Philosopher
Was the TX switched on when the changes occurred? Or off?
If off, the theory about random code jumps (perfectly valid IMHO) was
not teh case, it sounds much more like EM fields scrambling the flash
RAM.
To those who say 'the frequencies are different' I would suggest a we
search on EMP..mine came up with this sample...
http://www.geocities.com/CapeCanaveral/5971/emp.html
basically any strong EM field can do various things, from altering
computer memory, to burning out devices. Cell phones at millimeter
distances to sensitive electronics definitely have the potental to
disrupt MOS based digital circuitry, thoug the power stegs of a TX are
far less likeley to succumb.
The easy way to solve this is to maintain distances between the cell
phone and the TX. Inches are probably good enough...but slapping a
powered up cellphone againts a Tx case is the worst possible scenario.
Even if te TX is not switched on...
>
> Fritz
starcad
-snip-
Jack Goff
flight box, far away from my TX. It's not around me when I fly so I can't
answer it, but someone else can, or I just get the voice mail or caller ID
after I land. There's zero danger to anyone or any plane when I'm talking
on it at the tables or the fence, while people are flying 25+ feet away on
the flight line. Just use some "common sense"...
Jack
"Mark" <mst...@atlas.co.uk> wrote in message
news:IBUc8.1287$AX5....@news-binary.blueyonder.co.uk...
D SHANNON
like this idea as well as the ban from flight lines.
"Jack Goff" <cg...@sc.rr.com> wrote in message
news:uGXc8.22609$rs6.10...@typhoon.southeast.rr.com...
Jack Goff
consider the "flight line" to be the pilot's stations... and I do not take
the cell phone out there. Nor do I take it into the shed where the
transmitter table is. I don't want it next to my TX, so why would I want to
expose anyone else's?
Jack
"D SHANNON" <airp...@grm.net> wrote in message
news:a51tms$rk$1...@ins22.netins.net...
Micheal H. Gordon
tap!
--
Mike Gordon AMA 320990
Remember; RC Pylon Racing, the Ultimate Thrill,
when sex and drugs just ain't enough
Micheal H. Gordon
right there with you every minute of every day you need one of three
things. 1. Caller ID - 2.voice mail - 3. a life. Ya can't talk and fly
at the same time. If you think you can your full of "it".
--
Stephen
Same here. I keep it with me for emergencies, and leave it on my belt.
That keeps at minimum of a foot distance between it and any
transmitter, whether its mine, or one of my buddies. More than safe
enough based on the comments of experienced engineers, theory, and
testing they have performed, and the very few reports of possible
issues.
I never put it right next to any transmitter, nor do I talk on it
while in the pits or on the flight line. If I need to return a call, I
land, check caller ID, and call from inside my car.
If you really do need to keep them with you, keep then on your belt
when not in use, and only return calls from outside the pits or flight
line.
Stephen
Kurt Dorsey
there was flutter. The RX was the 7channel RX that Futaba bundles
with there TX and the phone was a nokia 61xx
The Natural Philosopher <a@b.c> wrote in message news:<3C72F2DB.ADB79E9A@b.c>...
The Natural Philosopher
Kurt Dorsey wrote:
>
> Yes, both the RX and TX were on, but I was not touching the TX when
> there was flutter. The RX was the 7channel RX that Futaba bundles
> with there TX and the phone was a nokia 61xx
>
Mmmm.
Thats a weird one.
So it was teh *RX* that was picking it up then, even when on full
carrier?
Not the TX digital circuits being affected.
I am not totally surprised at short ranges tho.
However, apart from field testing, your mobile phone is't likely to be
near the model in flight :-)
Thanks for replying. I am building up a mental picture of what does
interfere and what doesn't, which is useful...
The overall answer seems to be 'can interefere with boty rx and Tx, but
mostly it doesn't happen with cases of
- receivers picking up at close range (you)
- TX switched OFF being reprogrammed at veryt close range
No one yet seems to have had a TX affected whilst switched on, or have
they?
René
wrote:
Did u not forget the variable HF output from cellphones?
Aside - funny how this thread gets regurgitated on an ~ annular basis.
Good to see the correct answers also stay the same :-)
--
- René
Kevin Kline
"René" <r...@xs4all.nl> wrote in message
news:kd6d7ussqo6k72d9m...@4ax.com...
............................SNIP..................................
> Aside - funny how this thread gets regurgitated on an ~ annular
basis.
> Good to see the correct answers also stay the same :-)
> --
> - René
You mean the ones that say:
A. I am a self appointed expert!
B. I tried a few things (but by no means all possible combinations)
without any problems so the rest of you are just full of hooey!
C. I am a self appointed expert!
You meant like that? :)
K. Kline
Chris Dugan
news:0BKc8.5993$7X7.39...@news-text.cableinet.net...
>
<snip>
Thank Steve you couldn't have said it better myself:
Don't risk it.
Dave Stadt
Chris Dugan <cdu...@nospam.ntlworld.com> wrote in message
news:R6Ad8.16972$Ah1.2...@news2-win.server.ntlworld.com...
It sounded like a bunch of words that say nothing to me.
Ray Haddad
wrote:
It's far better than being a "Kevin" appointed expert. That means no
qualifcations what so ever except a rude, lying point of view.
Herbert M. Winston
What are you saying? Do you mean that Kevie's rude & has a lying point of
view? Nooooo, it can't be.
I'm devastated. (sniff) <V,VBG>
--
Herb Winston AMA 50438
28250 Pine Haven Way, #80
Bonita Springs, FL 34135-2841
USA
"He may look like an idiot,
and he may sound like an idiot,
but don't let him fool you.
He really is an idiot."
Mark Twain
"Ray Haddad" <rha...@iexpress.net.au> wrote in message
news:atge7u8gbd9i0j3g8...@4ax.com...
Dan Thompson
I fly at a field that has a cell phone tower within 400 feet on the pit side.
Also next to it is a FM radio station tower. Both of these towers have multiple
antennas on them. I don't know of any one that has had a problem that was
attibuted to them. I have scanned until I am blue in the face and have yet to
detect anything that I can say would cause trouble.
Dan
In article <R6Ad8.16972$Ah1.2...@news2-win.server.ntlworld.com>, "Chris
Dugan" <cdu...@nospam.ntlworld.com> writes:
>> FREQUENCY: While most fields do not recommend the use of cell phones for
>> liability reasons, there should never be a frequency problem between cell
>> phones and radio systems. The FCC makes sure that neither cell phones, nor
>> R/C frequencies are close enough in range to interfere with each other and
>> they enforce this policy actively. We have many fliers in high cell phone
>> use areas, who have never encountered frequency problems related to cell
>> phones, but once again, with the volume of cell phones today, and for
>safety
>> sake, it is best not to fly during a large amount of cell phone use in the
>> area of the flying field.
Dan Thompson (AMA 32873, EAA 60974, WB4GUK, GROL)
Remove POST in email address
Kevin Kline
The main problem being discussed is with the cell phone itself causing
problems with computer radios which are usually turned off. It has
nothing to do with the towers.
K. Kline
"Dan Thompson" <wb4...@aol.comPOST> wrote in message
news:20020223055003...@mb-fg.aol.com...
René
wrote:
>
The correct answers are the ones uttered by intelligent, well informed
and learned modellers. The ones I agree with, that is. :-^}
--
- René
Chris Dugan
> >
> >
> > Thank Steve you couldn't have said it better myself:
> >
> > Don't risk it.
>
> It sounded like a bunch of words that say nothing to me.
>
I meant to write ' Thank you Steve, couldn't have said it better myself'
>
> >
> > --
> > Chris
> >
> > Remove the "nospam." from reply address to reply
> >
> >
> >
> >
>
Blóódy Dyslexia.
Chris Dugan
news:20020223055003...@mb-fg.aol.com...
>
> I fly at a field that has a cell phone tower within 400 feet on the pit
side.
> Also next to it is a FM radio station tower. Both of these towers have
multiple
> antennas on them. I don't know of any one that has had a problem that was
> attibuted to them. I have scanned until I am blue in the face and have yet
to
> detect anything that I can say would cause trouble.
>
> Dan
>
Dan what frequencies do you fly on? It might be that in the US the towers
don't interfere with R/C flying but I'm in the UK and flying at that field
on 35Mhz has been proven by independent testing to be prone to interference.
I don't know what qualifications you have re: electronics or radio testing
but the club did pay for proper testing by government approved testers (who
reported to us, Vodaphone and the local council), so its not just my word
you are relying on.
Their report said that there was intermittent interference being generated
on and around the 35Mhz band by the cellphone mast and that we would have to
put up with it as Vodaphone have paid for the mast.
Dan Thompson
I know that alltimers is taking its toll on me. But, if I do remember the
thread is about cell phones interfering with RC. I do remember somewhere in the
cell phone threads a reference to flying near towers. Maybe it was the other
thread.
However, I think you will agree that cell phone towers operate on the same
frequencies as the cell phone we all have and at much greater power. I was
simply adding my experience since probably not too many fly as close to a cell
phone tower as we do.
In article <a57v5b$h1h$1...@bob.news.rcn.net>, "Kevin Kline" <kli...@erols.com>
writes:
Dan Thompson
Dugan" <cdu...@nospam.ntlworld.com> writes:
>Dan what frequencies do you fly on? It might be that in the US the towers
>don't interfere with R/C flying but I'm in the UK and flying at that field
>on 35Mhz has been proven by independent testing to be prone to interference.
>
>I don't know what qualifications you have re: electronics or radio testing
>but the club did pay for proper testing by government approved testers (who
>reported to us, Vodaphone and the local council), so its not just my word
>you are relying on.
We fly on 72, 50 and 53 MHz. The IF's are 455 KHz and 10.7MHz the same as
everyones.
The only testing I did was with a hand held scanner some time ago. I tried
hetrodyning several of the freq's to see if any would result in any of the IF
frequencies which could cause interference with a strong enough signal. I did
not do any spectrum anaylsis or elaborate testing as none was needed.
Matthew Orme
> at the same time. If you think you can your full of "it".
Really? Do it all the time, wehter it is with the other pilot standing bnext
to me, a spotter, or any other human around. Why would a cell phone with
hands free be any different?
Some of us CAN walk and chew gum at the same time. It's called multitasking
keith s.
>From: "Matthew Orme" Fred.Fl...@orme.org
>Date: 3/29/02 11:12 AM Pacific Standard Time
>Message-id: <z03p8.667$id3...@nwrddc02.gnilink.net>
Matthew, I bin away awhile(lurking) looking for places to fly in great NW(myth)
couldn't help but asking, "All well and fine my good man BUT can you fly
aerobatics whilst spouting off colour limericks and (1)keep a straight face (2)
not crash or (3) laugh."
I just can't seem to find any place to fly up here...dang.
Nefarious Necromancer 42nd class
oilburning hondas riden daily.
The more people I meet the more I like my dog.
Take out the crap to reply
Dave Stadt
Matthew Orme <Fred.Fl...@orme.org> wrote in message
news:z03p8.667$id3...@nwrddc02.gnilink.net...
Those folks in the big airplanes do it all the time also.
Six_O'Clock_High
"keith s." <sschi...@aol.comnilfeces> wrote in message
news:20020329143747...@mb-mn.aol.com...
Rider scale . . .
keith s.
>Rider scale . . .
>
>
sorry old boy that's a cheat and next time utilze the rudder to coordinate that
turn...
androidsma...@gmail.com
> Do Cell Phones Really Interfere with RC Radios?
>