acerc

And people wonder why people have issues with being hit!!

BadAzzMaxx

That was easy, just lubed it with your post and came right out.

Might even work for you if you give it a try.

Milton

Milton

eddieC

My Feedback: (2)

Try with a poorly shielded, dirty, wet plug connection. i.e.; real world, not pristine on a bench in a lab. Ever see a dirty distributor cap on a V-8 at night? It can glow like St. Elmo's fire under the right conditions. As for such a condition being 'poor maintenance/preflight' practice, it happens.

Oh, right. You can't be bothered doing a little research. That's OK, I'll do the work for you.

After an interminable 2-minute search:
http://rc.runryder.com/helicopter/t637995p2/ Page 2:
Same thread: http://rc.runryder.com/helicopter/t572943p1/ http://rc.runryder.com/helicopter/t506250p1/ I don't see where anyone called you a name, yet your response to badazz is simply rude. IMO you owe him an apology.
Sticks and stones, old boy...,

dirtybird

My Feedback: (5)

Since I asked you to do so I wiil respond:
I believe all radios, either FM/2.4 can be shot down, or suffer from interference no matter how much they harp on bullet proof, ect. If your flying 2.4 around power lines, or a huge amount of people your going down, or someone is. A phone, cell or land-line in the GHz range can cause problems. May not for some, but I've seen it.

He has an opinion I have mine. They differ. He offers no proof of his.

The BMFA (UK insurance), have made an advisory to all UK clubs that mobile phones should be kept away from flight lines.

You need to remember there are still people flying on 72 or 34(I think that is what the Brits use)

To put it very simply, if the noise level across the band of channels your 2.4gig system is flying on gets loud enough, your receiver won�t be able to decode its incoming data, regardless of its level of encryption or rejection.

Yea you got one. That is absolutely correct. Not very likely though.

t has nothing to do with the frequency we fly on, not even 2.4ghz is immune, it is radiated interference produced by cell phones that (COULD) not will, affect the electronic components inside the transmitter.
Can enyone honestly say they have not heard the speackers of a radio making a strange sound when a cell phone contacts the cell? it is electrical energy pure and simple. You may decide to just ignore the warnings, and never have an issue. But if ever an accident happens and it is down to this issue, will you be able to live with your conscience?

If you are trying to prove interference on 2.4 That is completely off the mark..

HoundDog

My Feedback: (49)

Bull Pucky Had a friend of mine and club member with a large model and a 50 cc motor with electronic ignition.
Long story short Spectrum 2.4 system range checked great with engine off. Every thing (servos) jumped around like a spasdick
as soon as the engine started. Would not range check at 10 feet. Turned out that the electronic inignation cut off was too close to the antenna on one of the satalite receivers. Moved them apart and all interference quit and the Range check passed at over 130 ft. Go Figure.

eddieC

My Feedback: (2)

Your opinion is based on lab tests. I don't fly in a lab.

35 in Europe IIRC. The BMFA recommendation was made after 2.4G phones came out. Again, we're talking real-world experience.

My point is 2.4G is no more 'bulletproof' than the advent of 72 Mhz after 27, PPM, PCM, etc. Each succession was an improvement, but was sometimes a band aid to poor installations. I've known many ace indoor fliers, some sponsored, who had lockouts (not brownouts or failsafe) with early Spectrum 2.4 that locked onto only 2 freqs. Fly near another user also on one of 'your' freqs, and he could knock your bird down. This also happened at Joe Nall a couple years back and was reported here. You'll have to do your own 'search' on that one.

As for '1 amp at full throttle', it's being stepped up to 40,000-80,000+ volts. Voodoo math.

Not that your points aren't valid regarding packets, etc, but the initial discussion was regarding gassers and 2.4. You've even admitted 2-3 times that it's possible. I agree with other system interfering, WiFi in FPV systems, etc.

I fly full-scale and had a client's new avionics 'glass panel' upgrade have issues; GPS and other failures, mainly at start-up. When I called the avionics tech and described what happened, he only asked one question, 'Did you have your cellphone on?' Turns out my cell's 2.4 interfered with the avionics, some of which also use 2.4.

I'm convinced 2.4G is NOT glitch-free. Why then did JR & Spektrum go to frequency-hopping? It's better, but (to me) still not bulletproof.

dbsonic

My Feedback: (3)

Can anyone point me to the errata for some of these RC systems?

speedracerntrixie

My Feedback: (29)

[QUOTE=eddie

As for '1 amp at full throttle', it's being stepped up to 40,000-80,000+ volts. Voodoo math.



I'm convinced 2.4G is NOT glitch-free. Why then did JR & Spektrum go to frequency-hopping? It's better, but (to me) still not bulletproof.[/QUOTE]


Sure it's stepped up to high voltage but it does not have much power behind it. Think ESD, lots of voltage but not much power.

sensei

I have been flying models since the 60s and 2.4 since 2006. That said my experience sides with Dirtybird because in 2007 I in fact setup a two battery system in a 40% gas model hooked up to a single switch providing power to a single 2.4 receiver and ignition module on the same circuit as a test bed. I have also flown that airplane and setup 100s of flights without a single hiccup, so just my own experience on the subject. Can 2.4 be hit, who knows for sure. My advice is to setup your airplane using best shop practices and get your own experience.

Bob

HoundDog

My Feedback: (49)

I'm not trying to start a Radio War but it seems that certain brands of radios have many more unexplained crashes "FOR NO PARTICULAR REASON". Saw 2 this week end Both same radios brand. One a big gasser with a large 4.8 volt battery and an apprentice. They both just dove into the corn. Nose Dived as the media would report it'

HoundDog

My Feedback: (49)

Just because U have flowen the same airplane for years doesn't mean that 2.4 can't have radio interference. I've seen it first hand a lot. But then again it always happens more with certain brand's of radio's. Also the question could be WHY is always the same people 99% of the time. May be just bad instillation practices. If U look in some of my planes it looks like a rat's nest of wires but never seem to ave any glitches.

HoundDog

My Feedback: (49)

I challenge anyone to start a "CRASH LOG" at their field and keep track of:
Pilot, Radio system, Battery voltage, Battery type and size. and neatness of instillation 1thru 5.
I did this one year and it showed some surprising facts. Mostly who was crashing a lot.

TRY IT U MAY BE ENLIGHTENED.

dirtybird

My Feedback: (5)

I dont have a lab. All of my instruments are portable. I can take them to the field if necessary.
I dont know what frequencies the brits use for cell phones. I do know the AMA has never issued a warning not to use cell phone at the field.
At my field there are at times 50 fliers at the field. I can guarantee every one has a cell phone in their pocket. There has never been an incident in the 14 years I have been here.
I worked at Boeing for 20 years. My daughter and son still work there. I know Boeing would never use a garbage channel like our 2.4 for anything. There are plenty of frequencies dedicated for A/C use that they could use. I think your tech is all wet.
My point is our 2.4 is far more bullet proof than 72 using anykind of modulation.
2.4 is not glitch free. There is a thing called multipath but thats another story.
I will not respond to any more of your posts

sensei

Hello,

Maybe you need to go back and read my post again... I stated Can 2.4 be hit, who knows for sure. My advice is to setup your airplane using best shop practices and get your own experience. In another post you stated he was flying a large gasser on 2.4 with 4.8 volts, I would not do that either, but maybe that is just me. I still agree with Dirtybird 2.4 is far more bullet proof than 72 using any kind of modulation, and I would not ever consider going back to 72...

Bob

rgburrill

As an EE who has worked with spread spectrum systems perhaps you can answer this question - do 2.4GHz RC systems use an IF in their receivers? One of the biggest problems that came about when 72MHz went to narrowband was the "23 channel" separation issue. Nearly all radios at the time, no matter what band they operated in, used a final intermediate frequency of 455KHz before demodulation. The difference in frequencies between two radios 23 channels apart was 460KHz. So if both were on a "beat" frequency was generated that could interfere with wide-band receivers that were even on completely different channels.
I realize this is simplistic and may not represent what is happening at 2.4GHz but it shows that if an intermediate frequency is used ignition noise could be interfering with it since it is downstream from all the protection one gets from frequency hopping and spread spectrum RF transmission. Isn't that why the recommendation is to keep the ignition control unit 12 inches away from the receiver?
BTW, I saw this happen in a most unusual situation one day. I used channel 47 FM and another of our guys used channel 24 FM. Both of us had narrow-band equipment. However we had another guy who had an older 5 channel PCM system of channel 40. While the first two of us were operating he turned on his system and his plane started jittering on all surfaces. Since I was only doing ground tests I turned my system off and his jittering went away. After that all of us started pulling frequency pins that were 23 channels away from our frequency when we pulled our channel.

dirtybird

My Feedback: (5)

I do not believe SS receivers use an IF system. Remember, SS is operating on many different frequencies. How they determine which frequency to accept is beyond my knowledge. You might ask Jim Drew on RC Groups.
The kind of problem you delineated will be eliminated with SS
.
I did a google search for ss receiver design and found this

http://web.ornl.gov/~webworks/cpr/v823/misc/109341_.pdf

It says SS does indeed use an IF. However an image frequency should not be a problem as it would not have the code

eddieC

My Feedback: (2)

I've known a couple folks who worked there, not a great place in their book but a steady paycheck.

Easy to check if you would be so motivated. I understand 2.4 is the predominant standard all over the world. There are plenty of other examples of cell phones disturbing helis on the RR site, over 10 years of incidents, many in the US.

Lol. Now I know you don't know what you're talking about. He does all my client's avionics installs, has been at it 30+ years like me. He was hand-picked by the company prez where he works just for his knowledge and skills, always in the know on new products and practices. He's the best I've ever seen, and I trust my life to his work.

Well then, my work here is done. (Joking) Not trying to offend, but there are other folks out there with experiences different than your own. You should keep an open mind.

There have been plenty of crashes with folks using 2.4, many of which had nothing to do with 2,4 itself, probably a bad installation, dumb-thumbs, etc. The troubling ones are the sponsored pilots with seemingly bulletproof installs, jet and heli guys with great installs, but seemingly impossible failures. Some have gone back to 72. Those failures are the troubling ones. There are also incidents reported of flying sites near power lines where 2.4 had the highest crash rates.

dirtybird

My Feedback: (5)

World standard fo cell phones,2.4?
check this out:
http://en.wikipedia.org/wiki/Cellular_frequencies.
I see only China listed as using 2.4

Your crashes near power lines is probably due to multipath.
If you dont know what that is try google

speedracerntrixie

My Feedback: (29)

Bob, I'm with you. I would NEVER use 4.8V on a 2.4 system. I too have been using 2.4 exclusively since 2008. I have had 2 crashes because of radio failure. The first was a regulator failure. The voltage input wires fatigued and broke free from the PCB. The second one was be caused I mistakenly used a receiver that had been crashed. These are what I call self inflicted failures. My current gasser would keep some guys awake at nite. The RX batteries are 2" away from the ignition, the throttle servo is 3" away from one of the plug wires and 1.5" away from a header. I use a Tech Aero IBEC. This airplane has about 40 rock solid flights. Part of that success ( although quite early in its lifespan) is that I'm using a power expander and all servo and power leads are twisted. Twisted wires are a subject of debate however even if there is no benifit, there is no downside either. Being that I have been flying models for 36 years, I can honestly say that these days I see far fewer radio related crashes then ever before and I see far more poor installations then ever.

sensei

Just about all my radio gear installations since I started using 2.4 include at least the throttle servo and batteries placed within 3 or 4 inches of the ignition module as illustrated in pics below with no issues at all. I have done this in several airplanes now so I don't suspect that you will have any issues with your installations either. I too see more poor installation on everything these days then ever before, that is why I made the statement a couple of posts back to use the best shop practices when installing whatever in airplanes. I know you have probably seen these pictures before but others may not have.



Bob

raptureboy

This is alot like the old tv show to tell the truth. Will the real electronics engineer please stand up. You have to scratch your head sometimes and wonder; the gas engine manufacturers sell small engines for 60 size planes which don't have enough room for the so called seperation needed for radio equipment and the radio manufacturers sell radios that claim to be bullet proof but just in case they say always follow proper installlation standards. I guess it all comes down to doing the best you can at trying to avoid trouble and count on the ability of the equipment to do the rest. I told ya dirtybird you better put on your flak vest

dbsonic

My Feedback: (3)

It's unclear to me the level of RF immunity in any of the ICs in the RX. Without knowing the shielding design and level of signal integrity checking in their effort to reach the market, I think it is best to follow the manufacturers advice as they have most likely done some RF environment vector testing during characterization.

acerc

Talk about the pot calling the kettle black, best shop practices would be to follow mfg's rec's. LOL! But I do the same plus a choke servo as well, plus a couple with a smoke pump right next to the ign just to piss it off......
Haven't pissed one off yet.

speedracerntrixie

My Feedback: (29)

This makes good sense, I'm betting that our cheapie radios use fairly low rated components or as industry calls them Class 1 and class 2. dbsonic, where do you fly? we may know one another.

dbsonic

My Feedback: (3)

pm'd ya