Went out flying today at my favorite spot up in the hills. The wind was calm so I flew my Pico stick first, then my modified Sky scooter. Both had GWS pico's in them. Then I flew my mini speed wing with a plantraco DSP4sc. It was getting hit a little but not too bad. Then a car parked down the road and when I flew by it, my plane went totaly out of control!!!! So bad that I had to shut it down. Lucky it weighs 5oz and landed in the weeds and not in the road. I walked up to the car that had pulled over and sure enough, they had stopped to talk on the cell phone. I've had a suspicion that cell phones were interfearing but this confirmed it. The GWS rx's glitched as usual, but the plantraco just totally lost it. When I picked up the plane it was spazzing out, servos were twitching like crazy. Not untill I got 30 ft away or so, did they calm down. I was flying my Butterfly in front of my house a few weeks ago when it suddenly nose dived into the ground from 30 ft. I lost all control, it too had a plantraco DSP4sc. When I went to pick it up in front of my neighbors house, his son was on the porch talking on the cell phone.
Has anyone else noticed this problem with your rx's?? I'm on ch 49. I wonder if that has anything to do with it. Butch
I guess you have 2 seperate problems. One is that the plantraco may get interference from cell phones. Second is that the dsp is very poorly written. The dsp should ignore all the bad commands and go into slow motion like the bergs. Then you still have limited control. It doesn't do that, but instead goes crazy with the servos going to extreme positions. You can read about it in this thread:
forums/showthread.php?t=280520
I have a Hi-Lite HLG with a GWS 4 ch. GWR 4P Pico Rx (single conversion type), was flying a while, decided to go back to the car with plane in hand(still on), unlocked the car (99 VW Golf) with the key remote and the plane went nuts!!!! I have never had a problem in flight though.
Definitely something to be said for dual conversion Rx's.
I only use the GWS ones in very light or somewhat expendable planes now.
Any other comments???????
Butch
Dual conversion has NOTHING to do with problems of over loading the front end of your receivers. What you both describe is what happens when the RX sees a very strong source of RF. Do you notice this problem (swamped) if you place another TX (72mhz RC TX), which is turned on and placed close to the rx?
PS, Dual conversion is only one of many ways to deal with the 460 kHz image problem common to our 72mhz frequency band and super heterodyne RXs.
Konrad
Originally Posted by Butch777
Any other comments???????
Butch
Well, there's this thread from awhile back:
forums/showthread.php?t=274355
This thread is related to use and potential interference from a cell phone in proximity to an Evo Tx. Mutliplex has already issued a warning about this, but in theory, this could be a problem for any brand or model Tx.
Note in the thread that a cell phone dramatically increases its RF output in the call setup portion of a phone call (with a cell station), before you even hear your cell phone ring on an incoming call. But RF output doesn't necessarily remain high *during* the call.
I won't try to draw any conclusions here because its a complicated topic and I don't consider myself an RF expert. But the thread is an interesitng read.
Lance
I don't turn my cell phone off when flying. It's on my belt and I never had a glitch not even when (or before) it's ringing. I also answered it once while I was flying my coroplast trainer - no glitches during the call either. All my transmitters are computer ones - Hitec's Flash 5X, Prism 7X and Optic 6.
Originally Posted by ivanc
I don't turn my cell phone off when flying. It's on my belt and I never had a glitch not even when (or before) it's ringing. I also answered it once while I was flying my coroplast trainer - no glitches during the call either. All my transmitters are computer ones - Hitec's Flash 5X, Prism 7X and Optic 6.
Yep, it appears to be a totally case-by-case issue. Some Tx and cell phone combo's will create problems, others are fine. From an engineering viewpoint, this makes sense because there are sooo many design variables, and usage scenarios, which affect susceptibility or lack thereof.
I would only say, just because its not a problem for one person, don't assume it won't happen to you. Run a few trials with a low-cost model before using a new Tx/cell-phone combo.
Lance
Hey guys,
I fly in a field behing my house and there is a large cell phone tower there... within a few hundred feet tops... I have flown with on CH 44 ,15 and 35 with all brands of TX's and RX's and I have yet to get a glitch... I even flew after my GWS 6RN RX antennae got cut in half after it came loose... I have a few Ariel pics from my SS flying circles around it... Never a problem...KNOCK ON WOOD!!!!
Myron
Originally Posted by Myron
I fly in a field behing my house...
Your situation is rather different to the issue here. What folk are talking about is direct injection of RF energy into their Tx from a very close cell phone. It enters via a variety of routes, typically not the antenna. Either directly through a plastic case, via the charge or trainer sockets etc. It typically affects some digital component of the Tx and can cause very odd and random effects.
Interference from a cell tower typically causes less frequent problems and only affects a Rx again due to proximity. Also usually injected via a route other than the antenna, and only when flying through a focussed microwave beam. I have never heard of a case where there is sufficient energy to scramble the Rx sufficiently not to recover until after a power down - unlike a Tx. Of course you may have crashed by then! Usually control is regained after flying through the beam.
Buildings and metal fences etc can cause some strange effects especially if a conventional transmitter is present somewhere nearby.
--
Steve |
Post at 2-6 01:21 PM
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