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2.4 Glitches - It Does Happen!

Old 06-07-2010, 04:58 PM
  #51  
JIMF14D
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Default RE: 2.4 Glitches - It Does Happen!

Ithink he does not test FASST because Futaba will not send him one.
Old 06-07-2010, 05:25 PM
  #52  
fatfreddy17
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Default RE: 2.4 Glitches - It Does Happen!



Loopman, usually a resistor plug has an R wriiten on the model number.

But this is not always the case, for my Homelite engineI installed a Champion 5851. My original plug was a DJ7Y ,and the 5851 replaces that plug and the RDJ7Y ( a resistor plug ). The nice lady behind the counter called the factory rep and asked if the 5851 is indeed a resistor plug - the answer is yes. Why it doesn't have a R in the number I don't know.

Bottom line the 5851 fixed the glitches I was getting.

Old 06-07-2010, 05:49 PM
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dirtybird
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Default RE: 2.4 Glitches - It Does Happen!

Here is what Jim Drew has to say about the guy that writes RCModelreview.

I wouldn't send this guy anything, and I wouldn't believe a thing he has to say either. He has zero ability to review anything. Let me explain...

Bruce Simpson is not an RF engineer. He never has been, nor will he likely ever be one. This is a guy who lives in New Zealand and one day he decides that he was going to build a working cruise missle (for measely sum of $5,000). After supposedly building it, he claims to have hidden it from the New Zealand and U.S. goverments. He got the attention of our CIA. There was a special either on 20/20 or 60 minutes about this guy. Because he refused to turn over this "cruise missle", the New Zealand government was kind enough to audit him. This put him in a bit of trouble, and he talks about it in the interview. The CIA realized that this guy didn't have the know-how to build a cruise missle, let alone one for $5,000, so they simply ignored him (but I am sure he is on some potential terrorist list somewhere - we don't forget). This is one of those genius guys that made a pulse jet engine and strapped it to go cart frame, and instead of placing it behind him, he placed it over top of his head - glowing hot - and no form for protection. Are you getting the picture yet?

So, sometime during the course of bashing our system he becomes a consultant for one of the Chinese 2.4GHz manufacturers and is suddenly an expert. Some people might remember him by his RCGroups name "XJet".
Old 06-07-2010, 06:03 PM
  #54  
JIMF14D
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Default RE: 2.4 Glitches - It Does Happen!

Well he was smart enought to figure out Hitec 2.4ghz was pretty good and Futaba is still hiding.
Old 06-07-2010, 06:08 PM
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dbspl
I'm not sure I follow this. There are 83 available channels in the 2.4Ghz band. Are you saying the data rate is reduced on just one of those channels, or the entire 2.4Ghz band? It would seem to make more sense if it were just 1 channel, but that also would leave you another 82 channels that would be uneffected.
The spread spektrum concept is that every .4 seconds the signal is transmitted over a different channel of at least 75 out of 83 channels available in a 30 second period.
Every 30 seconds the system has transmitted on at least 12 channels. As soon as you get 80 people flying (40 in the case of Spektrum) you are going to be sharing channels. As soon as you get 2 or more people flying you will have competition for those channels and that competition increases exponentially as the number of users increases. It also increase the amount of lag due to open channel searching and loss of data.

Channel sharing (multiple users on a single carrier frequency with digital identification) is almost identical to the technology used in ethernet (WIFI and wired). Sharing the channel reduces the data through put for each user on the channel. This has been the bane of computer networking for years and it is always a problem, not a solution.
Old 06-07-2010, 06:27 PM
  #56  
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dirtybird
....build a working cruise missle (for measely sum of $5,000)....
Without the warheads, that is about the right cost and pretty easy to make. Check the amateur rocket clubs. They build the equivalent of cruise missles all the time.
A nuclear bomb is even easier and cheaper to make as well. It is the weapons grade plutonium that is tough and expensive to get.

R&D is what costs a lot. Manufacture is pretty simple. I wouldn't trust either to hobby grade RC though.

Lets get back to the topic: 2.4Ghz RC
Old 06-07-2010, 06:28 PM
  #57  
cloudancer03
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Default RE: 2.4 Glitches - It Does Happen!

yes the rf enviornment isnt perfect.but the fm frequencies work well too.but I fly at various field and parks in florida over the winter and I am far more comfortable with 2.4 than fm and an honor system.as for glitches ,sadly my first 2.4 a few back was a DX7 and last winter it happened ..I breifly lost my signal and in a matter of 10 minutes I lost 2 very expensive planes due to a brown out.I had to buy a regulator from spectrum and decided to go back to futaba and never have had a problem since.and for the record I had a few glitches over the years unexplained flying FM.yup our radios can brownout but I gather the newe dx systems addressed that issue .and futaba never a proble,

2.4 was the best thing to come along in our hobby !! and hitec makes the aurora a very good system.

if you live in a rural area and nobody is competing for your frequency I am the first to agree why switch.but if and when you buy a new system it only makes good sense to go 2.4.I am thinking of buying the 2.4 module for my 9c tx and just be 2.4 I love the tecnology ..
Old 06-07-2010, 06:37 PM
  #58  
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Default RE: 2.4 Glitches - It Does Happen!

That is why the Hitec 2.4ghz system is so nice. You can use the Rx SPC port with a seperate battery or your EP lipo up to 35 volts. As I understand it, that way your Rx is protected from voltage drops from servo loads. You might still get a temporary link drop from RF problems but the Rx will fail safe and you should fly through it. Of course if it happens when you are doing a snap roll at 20 feet then you may have to use your garbage bag to take your plane home.

It will be interesting to see if new Spetrum stuff comes up with a copy of the SPC port for when the Dx8 comes out.

Jim D.
Old 06-07-2010, 06:39 PM
  #59  
dirtybird
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Default RE: 2.4 Glitches - It Does Happen!

ORIGINAL: dbcisco


ORIGINAL: dbspl
I'm not sure I follow this. There are 83 available channels in the 2.4Ghz band. Are you saying the data rate is reduced on just one of those channels, or the entire 2.4Ghz band? It would seem to make more sense if it were just 1 channel, but that also would leave you another 82 channels that would be uneffected.
The spread spektrum concept is that every .4 seconds the signal is transmitted over a different channel of at least 75 out of 83 channels available in a 30 second period.
Every 30 seconds the system has transmitted on at least 12 channels. As soon as you get 80 people flying (40 in the case of Spektrum) you are going to be sharing channels. As soon as you get 2 or more people flying you will have competition for those channels and that competition increases exponentially as the number of users increases. It also increase the amount of lag due to open channel searching and loss of data.

I think you are talking about frequency hopping here

Channel sharing (multiple users on a single carrier frequency with digital identification) is almost identical to the technology used in ethernet (WIFI and wired). Sharing the channel reduces the data through put for each user on the channel. This has been the bane of computer networking for years and it is always a problem, not a solution.
We are not talking about single frequency sharing here.
Lets look at what Wikiepia has to say about the generation of DSSS.
"Direct-sequence spread-spectrum transmissions multiply the data being transmitted by a "noise" signal. This noise signal is a pseudorandom sequence of 1 and −1 values, at a frequency much higher than that of the original signal, thereby spreading the energy of the original signal into a much wider band.

The resulting signal resembles white noise, like an audio recording of "static". However, this noise-like signal can be used to exactly reconstruct the original data at the receiving end, by multiplying it by the same pseudorandom sequence (because 1 × 1 = 1, and −1 × −1 = 1). This process, known as "de-spreading", mathematically constitutes a correlation of the transmitted PN sequence with the PN sequence that the receiver believes the transmitter is using."

Thus the data is spread over the frequency band of the channel in use.
Multi users can be accommodated by simply changing the seed for the PRN generator.
Old 06-07-2010, 06:44 PM
  #60  
Fs one
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Default RE: 2.4 Glitches - It Does Happen!

Have used Spektrum dx7 no problem whatsoever.2 guys that fly in the same club fly heli and airplane for 4yrs now.No problems at all.

                       Spektrum is where it's at.Go with the best and forget the rest!
Old 06-07-2010, 06:48 PM
  #61  
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: Loopman

it's an NGK BPM6F.
Loopman

Wrong plug, you need the BPMR6F. "R" for resistor
I get mine at NAPA auto parts.
Pete
Old 06-07-2010, 07:04 PM
  #62  
cloudancer03
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Default RE: 2.4 Glitches - It Does Happen!

as I said it was an earlier DX& and they acknowledged some issues the cost to resolve that was 6.00 and you plugged it into an open channel .2.4 system are inherently sensitive to voltage drops particularly below 4.8 which is why I switched all my batteries to 6.0 for some redundancy ..flying 4.8 ditigals etc on 4.8 is probably not the wisest descion thesedays.
Old 06-07-2010, 08:11 PM
  #63  
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Default RE: 2.4 Glitches - It Does Happen!

i just have to say it because it has come up .
there are poeple on here that are so insistant that 2.4 would NEVER GLITCH
it kills me to hear that it has and does !! ANYTHING electronic can glitch!!
and i do mean ANYTHING!!!
would just like to get it into some poeples thick heads ! i cant remember what it was that we were discussing ,but i was concerned as i was some that if it went wrong ,poeple could get
seriouslly hurt or killed , but when i mentioned it , it was like "oh i am useing 2.4 so i dont
have to ever worry about it "
Old 06-07-2010, 08:14 PM
  #64  
dbcisco
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Default RE: 2.4 Glitches - It Does Happen!

The more complicated things become, the more things that can go wrong... and will.
Old 06-07-2010, 08:48 PM
  #65  
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dirtybird

Spectrum does not have a patent on SS technology. That was patented by Hedy Lamar in 1939.
"THAT'S HEDLEY"
Old 06-07-2010, 09:18 PM
  #66  
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: rcslsafut

i just have to say it because it has come up .
there are poeple on here that are so insistant that 2.4 would NEVER GLITCH
it kills me to hear that it has and does !! ANYTHING electronic can glitch!!
and i do mean ANYTHING!!!
would just like to get it into some poeples thick heads ! i cant remember what it was that we were discussing ,but i was concerned as i was some that if it went wrong ,poeple could get
seriouslly hurt or killed , but when i mentioned it , it was like ''oh i am useing 2.4 so i dont
have to ever worry about it ''
WoW ! What happened to the original problem/question? Why is everybody so intent on proving the other one wrong about 2.4 glitching or not? Just read the owners manual they can and do brown out glitch out and whatever,which is why you should set up your failsafe settings and do a range check each time you go out to fly. It's not perfect but if you have been shot down a few times by someone turning on their radio then switch like I did. and set that failsafe We just had a guy land his plane and then have it go to full throttle when it browned out?? whatever, and came at us before nosing over.the guy didn't even know what fail safe was. Now what about that spark plug glitchy thing what solved the problem?
Old 06-07-2010, 09:21 PM
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Default RE: 2.4 Glitches - It Does Happen!


If you consider there are 50 dedicated channels in the 72 MHz band (total approx. 1 MHz), and the 2.4 GHz band is 85 MHz wide; you would think that if the 2.4 band were split up into dedicated frequencies (like 72), then the number of dedicated aircraft frequencies the 2.4 band could support would be aroud 4,250. It seems really odd that as few as 40 2.4 transmitters would be the limit using spread spectrum. I don't really believe that, but if it's true, it seems like an awfully inefficient use of bandwidth.

dbspl

Meeting adjourned...It Is?
Old 06-07-2010, 09:56 PM
  #68  
dbcisco
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Default RE: 2.4 Glitches - It Does Happen!

That is what the FCC dictates. 83 channels which are 1Mhz wide frequency bands. A channel is a simply another way of saying a frequency band. FM channels are also frequency bands. The difference is you have a channel all to yourself (hopefully) with FM. In spread spektrum you are not on the same channel for more than .4 seconds. One of the ideas behind this is that interference rarely happens accross an entire frequency spectrum. Sadly, this notion is, a priori, wrong. Noise, by its very nature and definition. is a wide spectrum phenomena.
Old 06-07-2010, 10:00 PM
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dbspl
the 2.4 GHz band is 85 MHz wide; you would think that if the 2.4 band were split up into dedicated frequencies (like 72), then the number of dedicated aircraft frequencies the 2.4 band could support would be aroud 4,250.
You have a range from 2400Mhz to 2483.5Mhz in 1Mhz increments. That is 83 1Mhz bands(channels).
Old 06-07-2010, 10:03 PM
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dbcisco

That is what the FCC dictates. 83 channels which are 1Mhz wide frequency bands. A channel is a simply another way of saying a frequency band. FM channels are also frequency bands. The difference is you have a channel all to yourself (hopefully) with FM. In spread spektrum you are not on the same channel for more than .4 seconds. One of the ideas behind this is that interference rarely happens accross an entire frequency spectrum. Sadly, this notion is, a priori, wrong. Noise, by its very nature and definition. is a wide spectrum phenomena.
Interference from noise (a very strong one) on the 2.4G frequency probably will never be encountered, unless somebody purposely wanted to do it.
Old 06-07-2010, 10:15 PM
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Default RE: 2.4 Glitches - It Does Happen!

ORIGINAL: Loopman

Well,
The distance from the engine to the receiver was 19 inches and the receivers antennas were positioned perpendicular to each other.
Loopman
How far from the engine was your closest servo? On another forum a guy set up his Giant Super Sportster with the throttle servo right beside the gas engine OUTSIDE the firewall. He got two flights before it crashed. A servo with those coiled windings is one big inductive RF receiver that pumps EMI back into the radio receiver via the wired connections. Does not matter the Rx/Tx frequency as a spark discharge is a broadcast on ALL frequencies. Keep the servos at least 8" away from the sparkplug, electronic ignition or magneto/coil.
Old 06-07-2010, 10:52 PM
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Default RE: 2.4 Glitches - It Does Happen!

ORIGINAL: nonstoprc

Interference from noise (a very strong one) on the 2.4G frequency probably will never be encountered, unless somebody purposely wanted to do it.
There is loa t of noise/interference on 2.4Ghz. You (RC) are sharing the same band with cordless phones, bluetooth and wireless computing and more. Does anyone use a bluetooth PDA, wireless router or cordless phone near your field? (and how would you know without searching houses and every car that drives by) They can all interfere with your 2.4Ghz gear. Guess what, they have priority over your plane as afar as the FCC is concerned. They can file complaints against you but not vice versa. I won't even mention my original Amana RadarRange that we use over three times a day (I could be crashing your planes a few miles away with that noise generating cyclotron).
All this nonsense about 2.4Ghz having no interference is just that...nonsense. Yes, FM does have problems with EMI/RFI, so does 2.4Ghz. As for as Spektrum, Futaba Et Al; scare tactics sell new products even if those new products are just as prone to problems.
I can't wait until the next generation of RC radio tech, everyone will be saying how bad 2.4Ghz and for a few hundred or thousand dollars everything will be perfect if you just buy the newest expensive offering from...
Old 06-07-2010, 11:00 PM
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dbspl


If you consider there are 50 dedicated channels in the 72 MHz band (total approx. 1 MHz), and the 2.4 GHz band is 85 MHz wide; you would think that if the 2.4 band were split up into dedicated frequencies (like 72), then the number of dedicated aircraft frequencies the 2.4 band could support would be aroud 4,250. It seems really odd that as few as 40 2.4 transmitters would be the limit using spread spectrum. I don't really believe that, but if it's true, it seems like an awfully inefficient use of bandwidth.

dbspl

Meeting adjourned...It Is?
The 72 frequencies are limited to a bandwidth of 10 KC
DSSS uses a channel 1mhz wide. Spectrum uses two channels. Some others use three.
FHSS skips over the entire 83MHZ band.
You have to give up something to get the plus factors you have on 2.4GHZ.
I would guess if you could get all the systems you need, you could get close to 4000 SS systems operating at the same time on the 2.4 GHZ band. You would probably have some degradation of performance
Old 06-07-2010, 11:19 PM
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dirtybird
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Default RE: 2.4 Glitches - It Does Happen!


ORIGINAL: dbcisco

ORIGINAL: nonstoprc

Interference from noise (a very strong one) on the 2.4G frequency probably will never be encountered, unless somebody purposely wanted to do it.
There is loa t of noise/interference on 2.4Ghz. You (RC) are sharing the same band with cordless phones, bluetooth and wireless computing and more. Does anyone use a bluetooth PDA, wireless router or cordless phone near your field? (and how would you know without searching houses and every car that drives by) They can all interfere with your 2.4Ghz gear. Guess what, they have priority over your plane as afar as the FCC is concerned. They can file complaints against you but not vice versa. I won't even mention my original Amana RadarRange that we use over three times a day (I could be crashing your planes a few miles away with that noise generating cyclotron).
All this nonsense about 2.4Ghz having no interference is just that...nonsense. Yes, FM does have problems with EMI/RFI, so does 2.4Ghz. As for as Spektrum, Futaba Et Al; scare tactics sell new products even if those new products are just as prone to problems.
I can't wait until the next generation of RC radio tech, everyone will be saying how bad 2.4Ghz and for a few hundred or thousand dollars everything will be perfect if you just buy the newest expensive offering from...
All equipment such as bluetooth and wifi are limited to 100mw. I suspect they use a lot less than 100mw. There is no need to drain their battery at the close range they require. Cell phone are not on 2.4ghz. I have never seen a cordless phone at the fields I have been to.
As far as microwaves I set my XPS system on the top of my microwave while both were operating. The XPS did not even know it was there.
Of course 2.4GHZ can be interfered with but all of the things we had to watch out for on 72 are just too low in frequency to bother 2.4CHZ with the exception of the spark plug. You need a resistor plug or good shielding on the plug and its lead
Old 06-08-2010, 07:07 AM
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Default RE: 2.4 Glitches - It Does Happen!

Also make sure the plug boot is all they way seated on the plug or it will not only make noise it will fry your ignition.

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