Cellphone interference?

No they won't - that is utter drivel.

Handheld GSM devices put out a maximum of 2W on a bad day with a tail wind (1W for GSM1800 handheld devices). And the "maybe more now" argument? Like some hidden cabal of no-gooders have spontaneoulsy and arbitrarly gone and changed the GSM standard? Causing the dastardly "swamping" of innocent chips and all their data?

I'll say it again - the microcontroller in the average R/C radio is a fairly feeble beast by comparison to almost any device on the market - their design and power is agricultural by comparison to an Ipod or a PDA, or a laptop.

Yet these *far* more complex and infinetly more powerful devices manage to survive *constant* close proximity to cell phones doing all their evil RF things, and they strangely, against all odds, survive.

Is it some conspiracy by JR & Futaba to make their devices distinctly suceptible to RF? Or perhaps it is some widespread slip-of-the-mind by the designers that they somehow make standard microcontrollers and memory extraordinarily vulnerable to RF, all to be placed in extremely close proximity to a R/C transmitter that pumps out, on average, *far* more RF power than a humble cell phone?

Bull. But please, tell us where you read this.

Do the math. Most cell phones have a single LiPo/Li-ion cell. So the voltage is 3.6 - 4.2 volts. Assuming 4 volts, you'd need to draw at least 5 amps from the battery to put out 20 watts, and that assumes that the transmitter is 100% efficient (and none is. 50% efficiency is a lot more likely, which would require 10 amps.)

And if you've ever tried to use a cell phone battery to power a plane, you'll realize that they can't put out 5+ amps reliably, especially the little ones.

| It's part of their housekeeping routine. The power out depends on | how far away from a tower they might be at the moment.

That much is true. But the _maximum_ power is less than 2 watts, and the typical power emitted is probably closer to 0.25 watts.

However, if your cell phone is only inches away from your R/C TX, the signal from it will be many orders of magnitude larger than the signal received by the R/C TX from the cell phone tower which is a few hundred yards away, even though the cell phone tower is probably transmitting with somewhat more power (it doesn't have to worry so much about draining a battery or the effects of RF on meat) and is transmitting to lots of cell phones at once.

You may find

to be informative.

| Don't believe me? Contact Motorola or Nokia. They'll tell you.

Yes, they just might, if you can find the right people. But they won't tell you 20+ watts.

Peak power is a long way from average power, if they are talking peak power it can easily be 4-6 times average power depending on how the signal is modulated, I don't know for sure what wattage these phones are capable of but I am skeptical that they would interfere with our R/C channels.

flierbk

| Peak power is a long way from average power, if they are talking peak power | it can easily be 4-6 times average power depending on how the signal is | modulated

And it is. Peak power = 1-2 watts, average power = 1/4 watt.

| I don't know for sure what wattage these phones are capable of but I | am skeptical that they would interfere with our R/C channels.

As am I. However, cases have been found where they do interefere with computer R/C transmitters under certain conditions, and these cases can be reproduced pretty much at will.

Personally, I think a cell phone is more a danger as a distraction than as something to interfere with your transmitter, but ...

| > You may find

to be informative.

You may as well. He measured the power output of a GSM phone ...

"Charlie Funk" wrote in news:d77gij$p3g$ snipped-for-privacy@news.valueweb.com:

Jest curious, I saw the video of its demise. What caused that fantastic big multi-turbine powered B-52 to dork in?

======== The "expert" analysis on this newsgroup concluded pilot error. Too slow, too much bank, stall, crash. Who really knows?

That is not the proposition. The proposition is that they interfere with the computer memory chips in the transmitters. Particularly the non volatile RAM. Given the incredibly tiny amounts of power needed to change a RAM cells contents, its certainly possible.

There is a reasonable amount of evidnce that they do do just that.

>

Pilot error and wind.

| > Peak power is a long way from average power, if they are talking | > peak power it can easily be 4-6 times average power depending on | > how the signal is modulated | | That is not the proposition.

Actually, in that case what I didn't cut out _is_ the proposition. (We've got a few proposition's going around.)

Recently, Chuck Jones claimed that

GSM phones can burst Tx up to 20W (last I read, maybe more now)

and I responded and basically said `no way', then Flierbk responded and said `Peak power is a long way from average power' which is certainly true, but the peak is 1 or 2 watts, not 20 watts ...

| The proposition is that they interfere with the computer memory | chips in the transmitters. Particularly the non volatile RAM. Given | the incredibly tiny amounts of power needed to change a RAM cells | contents, its certainly possible. | | There is a reasonable amount of evidnce that they do do just that.

Yup.

The Natural Philosopher wrote in news: snipped-for-privacy@spandrell.news.uk.clara.net:

From the video, seeing that it was bad weather rolling in, I was surprised someone would try flying. I don't know how many turbines he had, but it must have been at least 4. How many were there?

"Carrell" wrote in news: snipped-for-privacy@comcast.com:

They say an expert is a has been drip under pressure.

I'm curious how many turbine engines he had in that thing, must have cost him a fortune.

At least a modern .40 sets one back under $100, ducted fan higher. 4 ducted .40 fans = say 4 x $200 = $800. 4 turbines x $5,000 = $20,000.

Someone has money to burn.

It had eight Wren turbines. It's my understanding they were supplied under sponsorship by Wren. In EZone there is a thread mentioning that he's built a second Buff which has also crashed. It stated that AUW was some 60 pounds lighter than the first. Didn't mention how many engines, though. Bill(oc)

Wrong. I once designed cullular telephone stuff (both mobile and cellsite). The cellsites pump out _way_ more power than the mobiles. Mobiles put out somewhere between 0.1 and 3 watts. Handhelds only get up to about 0.3W. Cellsite transmitters are putting out a hundred times that.

True. The cellphone would have to be very close to the receiver to cause much interference.

That is seriously wrong. The cellsite PAs I remember working with put out at least 30W and some put out up to 100W. That was 800MHz AMPS stuff, but I'm pretty sure the same basic physics applies to other systems.

Like, um, cellphones for instance? ;)

Yea, that's it...

....as long as somebody doesn't start wrapping clothes hangars and tin-foil wrap around their transmitter antenna...it might start inteferring with the Police radars out on the nearest highway,... ;-)

Scroll about a third of the way down this site:

You'll see two videos about B-52 crashes. One is the model and the other is a real one. The two crashes are frightenly similar. The real Buff has "issues" with respect to it's lack of conventional ailerons. All it has are spoilers on the top outboard portion of each side. Basically they lack the authority to recover it from extreme attitudes. The pilot is responsible for keeping the aircraft within its flight envelope. The videos show two pilots who failed to do so.

Eight!

It would not surprise me to find out that today the power is much lower. However, I know what I read. Granted, it was several years ago and I no longer have the DoD white paper I read it in. But that doesn't make it any less incorrect. Nor does the fact that you have not personally experienced it.