Poor Transmitter Antenna Positioning may Cause Lockouts
04-20-2014, 07:17 PM
#101
Andy
3 lockouts happened at my field with Futaba 18, in all 3 we concluded that the problem was antena position, in all 3 the anntena was ponting sideways
Since we all are pointing it upwards not a single one has ocurred
we tested the theory doing a range check and when the antena was pointing directly to the plane we had lot less than half of the distance
BTW, I think this applies to every brand
3 lockouts happened at my field with Futaba 18, in all 3 we concluded that the problem was antena position, in all 3 the anntena was ponting sideways
Since we all are pointing it upwards not a single one has ocurred
we tested the theory doing a range check and when the antena was pointing directly to the plane we had lot less than half of the distance
BTW, I think this applies to every brand
Finally some good info, Also I have always heard that the tip of the ant should not be pointed at the plane in fact that was true for 72 mhz as well.
04-20-2014, 08:06 PM
#103
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Tony's accident happened at my home field and I also fly Futaba. I don't fly as fast or as far so Tony, but I would be more than happy test any combos you want in some of my lower priced planes. Now, the only other difference between the speed and range is I do NOT use PowerBox for anything, if someone wants to volunteer one, I can certainly test that too. Now, We know Tony was using one, and I am under the impression that the accident in PHX also had one, can we confirm if it was the same model/type? I have 2 10C and a 14MZ I can use to test with. Can we also look into finding out the TX's used when the planes went in? Also what RX and was there any of the new a-bus or telemetry? (I don't have or use that either). Let's first see if we can get details about the actual set up used.
Ralph
Ralph
I keep my antenna to the side because I always face the plane when I fly and the angle I hold the transmitter would point the tip of antenna right at the plane. I've flown almost a 1000 feet and mile away with no issues. Sideways antenna position has never affected a range check or flight.
I have only seen hard proof of two problems with FASST. One was a bad old nicad battery that was putting out about 2 volts under load. It caused some brownout glitching. Luckily the fast reboot capability of the FASST system allowed the plane to get home without damage. This was not my incident, but I was there and saw the proof as it was repeatable on the ground and the voltage was measured to be low enough to cause the problem. The second was a brownout that happened to me. I was using a Smartfly EQ10. I ran all but one servo off the board. Unfortunately I mistakenly plugged my rcexl ignition kill and throttle servo directly into the receiver instead of the power board. Oops. The two drew enough current to brown out the RX as the board only sends a small amount of power to the RX since it only needs power for the signal wires. I had no idea those two would overpower the system output, but it did. Luckily this was caught on the ground. I barely caught it, because the RX kept rebinding so fast. I was only just getting the slightest little glitch when I moved the throttle fast. I almost didn't notice it. Obviously a servo under a higher load could have made this worse, but could it glitch long enough to cause a crash? I don't think it's possible.
Obviously most of us know about the heat problems with the non-gold dot 6014FS. Futaba fixed it and the problems seemed to have gone away. Sure maybe there are some non gold ones still flying in hot climates, but I doubt it. Could any 2.4rx RX be overheated under the right conditions without the proper placement or ventilation? Sure. Unfortunately we don't know these details about the claimed lockouts in question.
The TX battery condition is another important issue. I have seen several planes lost to low TX battery condition. All have been JR and Spektrum. Now brand doesn't matter and the only reason they were all DSM units is probably just because of the odds by population. It's the same thing every time. The alarm goes off and 10 secs - 1 minute later it's all over. There is little or no warning before a complete and solid lockout occurs. This is a little different from the 72mhz days. Could it be possible that the Futaba TXs can lock out before the low voltage alarm? I don't know. I've never been close to that low of voltage. Anyone else?
I've also seen a fair share of damaged or poorly placed TX and RX antennas, switch failures, shorts circuits and wiring design problems throughout the years. Even the best can make system design errors or overlook damaged wires.
And finally, let's not forget good old battery depletion. I don't know anyone who hasn't forgotten to check their battery condition before. That's another deal breaker the accuser hasn't offered information about. I welcome more proof, but I'm always highly skeptical of lockout claims without details. This just isn't happening to FASST users as a whole. We already went from 8 supposed lockouts to only two possible lockouts. I have a feeling we could get close to zero if we got some honest first-hand feedback.
04-20-2014, 09:15 PM
#105
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Back to the antenna orientation. When I first started flying all my antennas / fishing poles pointed directly toward the plane. When you were a beginner your plane was often at times high and far away directly off the tip of the antenna, until your instructor brought it back.
04-20-2014, 09:24 PM
#106
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Why Speculate?
The 18mz on the latest update logs all the RSSI data on to the SD Card. It also logs all 18 channel positions and battery voltage going to Rx. If you have any on board sensors it will log them also.
I've had 2 crashes in the last year with that "what the heck happened" scenerio. One was a jammed Elevon, the other was an accelerated stall/spin. Both could have been chalked up to lockout without the telemetry data.
I do get a better RSSI (Relative Signal Strength Indication) with the Antenna pointed straight up. With it sideways you tend to fly into a null zone on the far ends of the field. Always stayed in control just the RSSI gets into the 2's and 1's rather than solid 3's. The RX won't lockout until you have a string of 0's. I've only been able to do that on the ground with my hand wrapped around the antenna at considerable distance.
Happy Flying,
Steve
The 18mz on the latest update logs all the RSSI data on to the SD Card. It also logs all 18 channel positions and battery voltage going to Rx. If you have any on board sensors it will log them also.
I've had 2 crashes in the last year with that "what the heck happened" scenerio. One was a jammed Elevon, the other was an accelerated stall/spin. Both could have been chalked up to lockout without the telemetry data.
I do get a better RSSI (Relative Signal Strength Indication) with the Antenna pointed straight up. With it sideways you tend to fly into a null zone on the far ends of the field. Always stayed in control just the RSSI gets into the 2's and 1's rather than solid 3's. The RX won't lockout until you have a string of 0's. I've only been able to do that on the ground with my hand wrapped around the antenna at considerable distance.
Happy Flying,
Steve
04-21-2014, 12:06 AM
#107
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I have a 12fg and 6014 rxs, never had an issue with it. It was one of the first in the UK and uses the separate plug in module. Recently I charged the Tx battery before flying and thought it stopped charging quicker than normal. During the flight the Tx alarm went off. We landed ok. It turned out the Tx battery had a cell go bad and has been replaced with a LiPo. I guess the battery was old and they do not last forever and needed renewing. In my experience lock out does not happen until well after the alarm goes off.
John
John
04-21-2014, 12:15 AM
#108
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Best Antenna position is the one where the TX is parallel with those on the plane most of the time. Always has been since 27MHz.The best scenario on the 2.4GHz aircraft is 3 antennas representing the three axis of the plane.
For those with only 2 antennas its probably best to avoid having one along the axis of the aircraft since in most cases it would be in a bad spot.
BUT only if the multi antenna system is any good.
Only good one I know of is the new JR (non xpxxxxxm) system.
For those with only 2 antennas its probably best to avoid having one along the axis of the aircraft since in most cases it would be in a bad spot.
BUT only if the multi antenna system is any good.
Only good one I know of is the new JR (non xpxxxxxm) system.
04-21-2014, 12:28 AM
#109
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Best Antenna position is the one where the TX is parallel with those on the plane most of the time. Always has been since 27MHz.The best scenario on the 2.4GHz aircraft is 3 antennas representing the three axis of the plane.
For those with only 2 antennas its probably best to avoid having one along the axis of the aircraft since in most cases it would be in a bad spot.
BUT only if the multi antenna system is any good.
Only good one I know of is the new JR (non xpxxxxxm) system.
For those with only 2 antennas its probably best to avoid having one along the axis of the aircraft since in most cases it would be in a bad spot.
BUT only if the multi antenna system is any good.
Only good one I know of is the new JR (non xpxxxxxm) system.
Some specifics beyond "big names" and "professionally built" to describe the equipment and environment would add something meaningful to the thread.
04-21-2014, 04:06 AM
#112
My Feedback: (5)
Recent solar storm causing weak radio freq to skipping from State to state 
? Your Tx ant is omnidirectional , orientation does not matter..your plane constantly changing it's receiving orientation. so rx installation is very important...So it's back to what's was in these plane before the crash, any video showing the lockout, (sign of high speed stall or does it goes straight in) pilot flying the wrong plane, or solar storm lol.
JUST MY OPINION
? Your Tx ant is omnidirectional , orientation does not matter..your plane constantly changing it's receiving orientation. so rx installation is very important...So it's back to what's was in these plane before the crash, any video showing the lockout, (sign of high speed stall or does it goes straight in) pilot flying the wrong plane, or solar storm lol.JUST MY OPINION
04-21-2014, 04:10 AM
#113
Bob
04-21-2014, 04:48 AM
#116
Well, a patch antenna does have more gain, but it comes at a price of being more directional - thus you have to keep it pointed at the plane for maximum gain. If you don't, you can easily get into a situation where the signal reaching the aircraft is less than it would be with a dipole...
Bob
Bob
Orientation of that di-pole antenna is a pita. Last summer I saw two pilots at a rally lose control of their jet on landing roll out at the end of a long runway because their antenna was pointed the wrong way. BTW, one of them did not have his failsafe set up correct so, instead of turbine shutting down, it throttled up and went four wheeling over the rough terrain past the end of the runway and tore his gear out.
Mike
Last edited by luv2flyrc; 04-21-2014 at 04:57 AM.
04-21-2014, 05:30 AM
#118
The one's I've seen Bob have a 180d dome radiation pattern so, unless you are flying behind yourself it's a huge improvement over di-pole. Also, the added gain is equivalent to almost doubling the power output. I see some of the Euro Tx's now using this technology but, for some reason F and J don't seem to be on board.
Orientation of that di-pole antenna is a pita. Last summer I saw two pilots at a rally lose control of their jet on landing roll out at the end of a long runway because their antenna was pointed the wrong way. BTW, one of them did not have his failsafe set up correct so, instead of turbine shutting down, it throttled up and went four wheeling over the rough terrain past the end of the runway and tore his gear out.
Mike
Orientation of that di-pole antenna is a pita. Last summer I saw two pilots at a rally lose control of their jet on landing roll out at the end of a long runway because their antenna was pointed the wrong way. BTW, one of them did not have his failsafe set up correct so, instead of turbine shutting down, it throttled up and went four wheeling over the rough terrain past the end of the runway and tore his gear out.
Mike
Notice that the 3 dB beam width is only 60 degrees. Higher gain from a passive antenna *requires* more directionality...
Bob
04-21-2014, 07:04 AM
#124
My Feedback: (21)
Years ago, when we were flying 27 mhz Kraft had problems with signal strength in areas of low soil moisture content, IE the desert southwest. Our radios use ground plane antennas. The electrical conductivity of the soil has an effect on the signal strength. Since the lockouts described were in "the west" it is possible that soil conductivity played some role in the problems.
It only takes a slight drop in signal strength under the wrong conditions to unbind any of the 2.4 radios. Due to the way 72mhz works this was never a problem so it may have suddenly
popped up again with 2.4.
Larry
P.S. I have had a World Engines Blue Max 27mhz radio for over 40 years and it has never given me a problem
Of course it's been in a box for 30 years!
It only takes a slight drop in signal strength under the wrong conditions to unbind any of the 2.4 radios. Due to the way 72mhz works this was never a problem so it may have suddenly
popped up again with 2.4.
Larry
P.S. I have had a World Engines Blue Max 27mhz radio for over 40 years and it has never given me a problem
Of course it's been in a box for 30 years!
