Is there a radio that does not lose signal?
08-13-2012, 06:53 AM
RE: Is there a radio that does not lose signal?
Guys
I'm just looking for the radio system that has the least amount of problems that I have been facing. I really don't think it's that hard of a question.
08-13-2012, 08:50 AM
RE: Is there a radio that does not lose signal?
Well they found that my radio had great signal but the receiver was glitching. They gave me a new receiver and helped me replace the parts on my Sundowner. My answer to you is this...
Find a radio that has the kind of support that was provided to me, the support is what matters the most to me (next to it working of coarse). We are dealing with electronics that we put a lot of stress on and when they fail which all will do at some point it's what the radio company does next that keeps me with the brand that I use. Just my opinion.
Oh and a more direct answer to your question... No there is not a radio/receiver combination that is bulletproof and won't lose signal, all have the potential to fail.
08-13-2012, 08:51 AM
RE: Is there a radio that does not lose signal?
control line
At least I always knew exactly where to go to pick up the pieces, I never had to track thru corn to find the wreckage.
Andy
08-13-2012, 10:19 AM
RE: Is there a radio that does not lose signal?
But if you will install it right and use fresh batteries you will minimize the problems to virtually zero.
I use Futaba 12FG today, no problems.
Had only one problem in the past with 9C 72 due to a crystal fail [:@]
08-13-2012, 11:01 AM
RE: [Awaiting Approval]
http://diydrones.com/profiles/blogs/...ource=activity
08-13-2012, 01:56 PM
RE: Is there a radio that does not lose signal?
We have had a few say 5 crashes at our field in the past 2 years where guys say they lost control of the plane. I can't speak for them but I know what happened to me. I know 99.98% or crashes are caused by human error. That's not to say a radio can't be the fault. So that leads me to look for a new radio.
What else would you do? You have a new plane, a new receiver with a satellite and a fully charged battery that is the exact size the manufacturer recommends. You have range checked the plane and all looks good. You fly about two mins and then while you are flying a pass from right to left down the runway about 50ft high the plane rolls right and dives into the ground at full throttle. As the plane is rolling out you yell I don't have it and hold up the radio while moving the sticks around and the plane continues to dive into the ground. What error could you have made that would cause that plane to crash? Now look back about three months you had another plane do almost the exact same thing but it was going the other direction and rolled out left. You sent the radio back to the manufacturer and they gave it a clean bill of health. What would you do?
How do you have a field analysis done? How much would that cost?
I feel your pain and completely understand where you are coming from. I've wached quite a few planes go in due to loss of control. In all cases the pilots were expereinced chaps and the symptoms are the same. good battery, range check ok, and theres control during take off and even for a few minutes then nothing.
Watched a mate throw a Nine eagles Skyclimber off the slope last thursday. Everything worked till it was gently flung off the slope. Suddenly no control. We retreived it, dusted it off and flew it again for an hour, not problems.
I think some of the 2.4 radios simply have compromised software with less than adeqaute error checking and correction. The rx "hangs" and does not reboot properly, just like some computers do.
08-13-2012, 02:11 PM
RE: [Awaiting Approval]
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2.4GHz: Is It All It’s Cracked Up To Be?[/b]
Asubstantial number of unexplained crashes of radio control model airplanes on2.4GHz frequency prompted me to write this article on the so-called“interference free” radio control systems on the 2.4GHz band.
The electromagnetic wave spectrum is subjectto the immutable laws of physics.[/i]
Thepropagation characteristics of the 2.4GHz wavelength and the environmentaleffects of this frequency are more complex than on the 72MHz band. To better understand this, we have to look atthe electromagnetic wave spectrum where 72MHz band is in the broadcastingregion and the 2.4GHz band is in the microwave region. It is easier to see the huge differencebetween 72MHz and 2.4GHz frequencies when we convert 2.4 gigahertz tomegahertz. Now it is 2400MHz versus72MHz. When frequency increases,wavelength decreases. Therefore, the2.4GHz wavelength is shorter and closer to visible light on the electromagneticwave spectrum. Since visible light isalso an electromagnetic wave, 2.4GHz wavelength behaves more like visible lightand travels in straight lines until it is reflected, deflected, diffracted orabsorbed. Reflection and diffractionwill create interference. [/i]
Whenparallel rays of light are reflected by a concave mirror, it greatly increasesthe intensity of light at the focal point. A parabolic dish antenna works the same way for a 2.4GHz electromagneticwave. Since we can not focus a high gaindirectional parabolic dish antenna between our constantly moving model airplaneand our transmitter, we have to use an omnidirectional vertical antenna systemwhich has much lower signal intensity.[/i]
[/i]
Interference[/b]
The FHSS(frequency-hopping-spread-spectrum) and the DSSS(direct-sequence-spread-spectrum) techniques can share the same band. However, they interfere with each othercausing a degradation of performance. Range decreases as the number of clear channels decreases. Bandwidth drops each time FHSS encounters ablocked channel on a crowded spectrum.
The crowdedspectrum on the 2.4GHz band reduces the bandwidth, increases the ever presentbackground noise, increases the adjacent channel leakage ratio, reduces the range[/i], and causesoverlapping. Overlapping is a direct interference.[/i]
Unlike the72MHz wavelength which penetrates most objects, the 2.4GHz wavelength behavesmore like visible light. Signalabsorption from objects on a model airplane like the engines, electric motors,batteries, servos, pushrods, landing gears, switches, wires, etc., may causepath interference.[/i]
Signalreflection from objects in the terrain, like fences, walls, buildings, trees,hills, power lines cause line of sight interference. [/i]High speed data transfer reduces thereceiver’s sensitivity on 2.4GHz band. There is a trade-off between speed versus range.
The signalstrength decreases quadratically as distance increases at constant radiationlevels. This is called path loss. When frequency increases, path loss alsoincreases. This is one of the reasonswhy 72MHz radios have a better range than the 2.4GHz radios. We can see this clearly when we look at theWireless Range Calculator:
Frequency Distance Loss
100MHz 0.2 mile 62 decibel
2400MHz 0.2 mile 90 decibel
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These calculations are under non-existing ideal conditions,less Fresnel (pronounced Frehnel) effect.
When we flyour model airplane on 2.4GHz, the area around us is known as the Fresnelzone. Since we have to use anomnidirectional antenna system, the electromagnetic waves will scatter and diffractfrom objects and from the terrain around us. When the diffracted wave reaches the receiver antenna, it is slightly lagsbehind the signal which traveled to the receiver antenna in a straight linethat creates interference[/i] due to thephase canceling effect.
The Fresneleffect also deals with the behavior of electromagnetic waves over a watersurface. As mentioned before, the 2.4GHzradiation behaves more like visible light, so we have to think of reflectionsand shadows. Flying a 2.4GHz radio controlmodel over a reflective surface like water, snow, ice or wet terrain negativelyaffects the radio link. Occasionally a3D aerobatic model plunges into water while hovering. When the rudder is near the water surface,the prop wash creates a chaotic wave pattern which generates a myriad offalse-signals.
The Fresneleffect and the described interference on the 2.4GHz band work pretty well. We successfully tested this at differentlocations. Unfortunately, the“unbreakable Tx-Rx link” broke when our model was over 0.2 miles away at 45degree angle. Despite the fact that a 90decibel signal loss over a thousand feet (0.2 miles) is rather significant, weshould have had control at this distance. There are too many factors that can determine the overall range on2.4GHz.
2.4GHzreceivers are not immune to ignition and electrical noise as advertised. Occasional arc from high tension insulatorscould break the bind.
Latency[/b]
Latency isthe time between stimulation and the beginning of response caused bypropagation delays. There is a huge timedifference in latency claims by different radio manufacturers. Some latency claims are in milliseconds,others are in microseconds! This isconfusing since one millisecond is one thousandth of a second and onemicrosecond is one millionth of a second.
Velocity ofelectromagnetic waves is 186,283 miles per second. The velocity of the electric signal throughconductors is nearly at the speed of light. With an adequate power output, our radio signal will travel onemicrosecond which is one millionth of a second to reach our model airplane onethousand feet away. This applies to allbrands of radios on 72MHz or on 2.4GHz. As we know, nothing travels faster than the electromagnetic waves. Therefore, I don’t see how latency could beimproved “50 %” over the leading competitors regardless of differentprocessing.
A sevenmillisecond latency or a fourteen millisecond latency claim is irrelevant sincethe human being, the RC pilot, has a painfully slow 200 millisecond latency andcan not differentiate between seven or fourteen milliseconds.
Conclusion[/b]
At huge events,like Nationals, the 2.4GHz pin-free radio system makes life easier forcompetitors and organizers. However,there is a huge difference between flying on 2.4GHz band in the beautiful countryside near Muncie where chances are good that there won’t be any
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noticeable[/i]interference and flying on 2.4GHz band in the middle of one of the largestconcentration of population and industries in Los Angeles or other urbanareas.
2.4GHzradios under harsh conditions work most of the time, however most of the timeis unacceptable. Illegal signal boosting,ham radio, and rolling hills further aggravate the situation. 2.4GHzwavelength has much higher incurred losses than 72MHz wavelength. Therefore, when it comes to range, the 100mWRF output on 2.4GHz radio is no match to a 750mW RF output on 72MHz radio. When out of range, error correction, uniqueGUID code, and the “robust” pseudo-random control sequence will do no good. In any case, we should hold on to our assigned[/i] frequencies on 27MHz, 50MHz,and 72MHz bands.
Despiteglowing reviews, the so-called “bulletproof 2.4GHz technology” has range andreliability problems since day one. Abench test inside a building in a controlled environment where the receiver isa few inches away from the transmitter is meaningless.
2.4GHzwavelength is not the best choice to control model airplanes. Furthermore, we have ended up with complexradio systems on an overcrowded band on the electromagnetic wave spectrum.
The bottomline is that glitch-free software, error-free computers, and aninterference-free radio link is only an illusion.[/i]
[/i]
Dave Horvath
11-11-11
References:[/b]
[/i]
electromagnetic spectrum
Images for electromagnetic spectrum
Videos for electromagnetic spectrum
Frequency-hopping spread spectrum
DSSS and FHSS-Spread Spectrum tutorials
2.4 GHz interference
Interference in the 2.4GHz ISM Band:
Challenges and Solutions by N Golmie
20 Myths of Wi-Fi Interference (RF Solutions)
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path loss in the 2.4GHz
Speed vs. Distance ISA
900 MHz versus 2.4GHz – Learning Center
fresnel zone
Images for fresnel zone
ZyTrax-Fresnel Zones and their Effect
diffraction
Images for diffraction
Diffraction-Wikipedia
polarization of light
Images for polarization of light
Videos for polarization of light
MIT Physics Demo-Microwave Polarization
2.4GHz spread spectrum problems
2.4GHz Spread Spectrum problems
Wireless Range Calculator
Free Space Loss
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08-13-2012, 02:28 PM
RE: Is there a radio that does not lose signal?
* remember all radios meet FCC requirements and there is no such thing as 100% guarantee. everything can have transmission interruption.
08-13-2012, 08:19 PM
RE: Is there a radio that does not lose signal?
Going out a few miles FPV illegal, dangerous and stupid. Thanks for jeopordizing our hobby for the rest of us.[img][/img]
http://www.suasnews.com/2011/03/4833...cident-report/
This guy has already done more damage than ANY fpv flight has ever done and has set the wheels in motion. The FAA does not forget about stuff like this.
If you cant fly at a event with multiple spotters and radio communications with the tower and not bring down a full scale there aint no rules in the world that will save ANY part of RC.
Might as well call down all the glider guys too while we're at it.
Theyve been well above 400' for YEARS.
08-14-2012, 03:56 AM
RE: [Awaiting Approval]
The Pilot of the Full Scale BiPlane LIED about trying to land and then go around. He was making a high speed Smoke on LOW PASS, and furthermore when the BiPlane HIT the Model, the Model was on the other side of the runway.
08-14-2012, 05:36 AM
RE: [Awaiting Approval]
08-14-2012, 05:44 AM
RE: [Awaiting Approval]
08-14-2012, 08:46 AM
RE: Is there a radio that does not lose signal?
Guys
I'm just looking for the radio system that has the least amount of problems that I have been facing. I really don't think it's that hard of a question.
Personally I am not a big fan of the whole antenna placement. If I have Cf in a fuse, it can interfere, or other such stuff to worry about. I just prefer to hang my 72 out the back to the tip of the tail. For me so far that has been working.
Best of luck.
08-14-2012, 09:50 AM
RE: Is there a radio that does not lose signal?
We have had a few say 5 crashes at our field in the past 2 years where guys say they lost control of the plane. I can't speak for them but I know what happened to me. I know 99.98% or crashes are caused by human error. That's not to say a radio can't be the fault. So that leads me to look for a new radio.
What else would you do? You have a new plane, a new receiver with a satellite and a fully charged battery that is the exact size the manufacturer recommends. You have range checked the plane and all looks good. You fly about two mins and then while you are flying a pass from right to left down the runway about 50ft high the plane rolls right and dives into the ground at full throttle. As the plane is rolling out you yell I don't have it and hold up the radio while moving the sticks around and the plane continues to dive into the ground. What error could you have made that would cause that plane to crash? Now look back about three months you had another plane do almost the exact same thing but it was going the other direction and rolled out left. You sent the radio back to the manufacturer and they gave it a clean bill of health. What would you do?
How do you have a field analysis done? How much would that cost?
I feel your pain and completely understand where you are coming from. I've wached quite a few planes go in due to loss of control. In all cases the pilots were expereinced chaps and the symptoms are the same. good battery, range check ok, and theres control during take off and even for a few minutes then nothing.
Watched a mate throw a Nine eagles Skyclimber off the slope last thursday. Everything worked till it was gently flung off the slope. Suddenly no control. We retreived it, dusted it off and flew it again for an hour, not problems.
I think some of the 2.4 radios simply have compromised software with less than adeqaute error checking and correction. The rx ''hangs'' and does not reboot properly, just like some computers do.
BTW the instigator of the latency problem was the Futaba 1024 PCM system. It used two RF frames to update the servo pulses. Thus there was a visible delay of servo pulses downstream from the control pulses. This is just one of the things 2.4 cured because of its greater bandwidth.
900mhz would have been a better choice but for one problem. The availability of low cost chips on 2.4 and not on 0.9GHZ
08-14-2012, 10:58 AM
RE: [Awaiting Approval]
I have no beef with 2.4GHz radio technology in general. Some are definately better than others
08-16-2012, 02:35 PM
RE: Is there a radio that does not lose signal?
12-17-2012, 09:50 PM
RE: Is there a radio that does not lose signal?
12-19-2012, 01:05 AM
RE: [Awaiting Approval]
Remember that early life failures, and failures due to "unknown" causes are a fact of life when it comes to solid state electronics.
Even with that, the failure rate is much less than it was with tube based equipment. Modern receiver sensitivity and noise rejection is also much better than it was in the past. (Park flyer receivers excepted)
I've had "unexplained" failures as well. In retrospect, it's possible that they were caused by a combination of things, involving receiver battery current and voltage capability, along with possibly higher than expected servo current draw. What was most puzzling about failures involving two different models and electronics? A partial ability to control the models was regained, in that one had aileron control, with limited motor speed control, and the other elevator control and nothing else. Both models survived intact, and were later flown successfully. Both passed ground range checks well beyond the failure distances. When voltage was re-applied after the "crash" shutdown and ensuing inspection Normal operation was the case.
What changes were made to possibly help matters?
The ESCs (SC internal) were replaced with an external ESC with double the current capability. ~5A as opposed to 2.5-3A.
All servos and throws were checked, and where necessary, adjusted so that the control surface mechanical stops and the servo internal stops
would not be a factor that might cause high current draw. ESC voltage was increased from 5v to 5.5 or 6v. The internal BECs were fixed at 5v.
One model has five digital servos, and the other six. Under "normal" conditions, the current draw per servo is much less than 200ma, as indicated on a current meter. Both receivers were rebound, with care taken to make sure that no TX signal, fail safe, and so forth behaved as expected.
I also found another possible cause that can be speed control/setting dependent by adding telemetry to one of the models.
Most speed controls sense LiPo battery voltage, and revert to lower power or burst power to the motor when the voltage drops to a certain point.
Under full throttle, the battery voltage will drop. If it drops far enough, the speed control may reduce power to the motor, and allow the battery voltage to rise enough to go above the low voltage sensing range. If a high enough throttle setting exists, the speed control may "cycle" between a low power output and a high one. The resulting electrical noise may have some effect on the RX. I also saw some glitch counts/indications that were greater than usual when burst power to the motor had occurred.