SPEKTRUM DX7 SHOT DOWN!
I had a lot of faith and confidence in the SPEKTRUM DX7, so I decided to go ahead with the integration of the hobby wireless 500mW 2.4GHz AV TX into my UAV. I plugged everything in, conducted a range test and proceeded to take-off. Video Feed was great and I was in CONTROL......so I thought. after about 45 seconds and a partial loop around my airfield I lost control of the aircraft. Luckily my failsafe settings kicked in and the aircraft began its gentle right hand glide.....10 maybe 15 seconds went by then I regained control of the aircraft and attempted to circle in for approach...lost control again. This went on for about 2 minutes until there was no longer enough air between the aircraft and the ground to be considered "flying". Yes it all ended in a crash. Luckily a pine tree had softened the impact with the ground and the only damage was to the wing which is very easily replaced. after this whole situation I conducted a little investigation and came up with something that I should have checked prior to my flight. 1) frequencies. the DX7 operates in the 2.400GHz - 2.4835GHz range and the hobby wireless 2.4GHz 500mW AV TX operates from 2.410GHz(CH 1)- 2.510GHz(CH8) 2) Although SPEKTRUM claims BULLETPROOF link in all conditions...everything has its weakness. (I STILL HAVE FAITH IN MY SPEKTRUM RADIO!) I conducted a taxi range test with just my fuselage and with the same set up as yesterday when I crashed but I changed the Freq. on the AV TX to CH 8 - 2.510GHz.....just out of the SPEKTRUM's freq. and the system worked without interference out to and beyond the approx distance of the incident yesterday....so far so good. Once I get a replacement wing I will do some more testing prior to flying again, but I am fairly confident that the freq. change made a world of difference. Anyone out there have anything like this happen? If so, feel free to add to this discussion!
Replies to This Discussion
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Permalink Reply by Sgt Ric on -
Right UFO-Man, ...I thought this was a given by now, but every once in a while we get some 2.4 ghz enthusiast who gets defensive and argues the point.
It has been proven over and over that the 2.4 video "swamps" the RC signal... not always right away or at the launch site itself, but once iin the air it overpowers the received signal by brute force.
There has been documented eviidence here and at rcgroups.com especially.
Sure someone can occasionally recite an exception - just like my uncle's neighbour who smoked 5 packs a day since he was 10 and lived to be 97 before being hit by a bus and never got cancer (or was it my neighbour's uncle?)
The point is, don't risk mixing 2.4 video with 2.4 RC!
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Permalink Reply by OpticalFlow on -
I just came across this old thread when doing some research on the web as to the best video TX frequencies to use with DSM2 rc gear.
One of the other things that came up was this article:
http://www.rcmodelreviews.com/dsm2flaw.shtml
This suggests that I may work without problems sometimes (when DSM2 picks two well-seperated frequencies) but can fail at other times when the frequencies are too close together.
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Permalink Reply by Ryan on -
Spektrum 2.4ghz doesn't fully take advantage of the freq. hopping - when you turn on the system, it locks on to 2 open channels and hop between them.
So you can imaging that eventually your 2.4ghz video Tx. will step on your 2 Spektrum channels.
Futaba FASST system actually continously hop between all the channels in the spectrum.
I use Futaba FASST with 2.4ghz video Tx without any issue full stop!
I think it's still best to use a different freq. for video especially if it's high power Tx. because can still degrade the signal quality of your 2.4ghz RC gears.
Please don't start the Spektrum vs. Futaba war - I just want to let you know what works.
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