EZUHF Epic Fail - Crash

[Flyn]

http://youtu.be/ylMLqILq_74

[FPVSteve]

Not good at all, will be interesting to see what caused it.

[Flyn]

Yeah too right on both counts fella.

I did my reading I set everything up as spec'd & it just said "no - im gonna cost you a dick load of money" instead. Thanks ImmersionRC.

[Coyote]

Have you got any pictures of the install, see if there might be any clues ( pre crash photos )

[Flyn]

nah sorry fella, no pics.

it's motor at the front, esc behind at front of fuselage. FPV cam on leading edge of wing (centre), vtx 1"  behind. EZUHF on tail 2-2.5ft behind with antennas in a V position with short servo extension leads.

[FPVSteve]

Maybe the UHF was shielded by the FPV gear because it failsafed when you were coming back (so your gear was between your Tx and the UHF Rx)

[Flyn]

Could be, but I was on the way out when it went (21sec on vid). I programmed the failsafe to zero throttle, right rudder & a little bit of up elevator, so thats why it turned back, by that time it was totally gone.

[simondale]

Hi Flyn,

Sorry to see this happen.  I just got on Skype with Anthony at ImmersionRC and he pointed me in the direction of your thread on http://fpvlab.com/forums/showthread.php?8088-Sad-to-say-EZUHF-Epic-Fail-amp-Crash-Vid

He was at the meet in Canada and saw the same thing happen with a Spektrum DX8/DX18.

He's updated the "compatibility spreadsheet" here: https://docs.google.com/a/firstpersonview.co.uk/spreadsheet/ccc?key=0AmVt8U67J0EWdHRkcXhqSjFja3VlcGRadUp1Sk5FM0E#gid=4

I'll put a message on our website warning about an incompatibility with DX8/DX18 and UHF systems.

Let me know how I can help with this.  It looks from the end of your video like the EzUHF is intact and working?

All the best

Simon

[Coyote]

Just had a second look at that video, it looks to me like the 2.4ghz board is still in, so powered up and therefore an active 2.4ghz antennas still in the circuit

[Flyn]

Hi Flyn,

Sorry to see this happen.  I just got on Skype with Anthony at ImmersionRC and he pointed me in the direction of your thread on http://fpvlab.com/forums/showthread.php?8088-Sad-to-say-EZUHF-Epic-Fail-amp-Crash-Vid

He was at the meet in Canada and saw the same thing happen with a Spektrum DX8/DX18.

He's updated the "compatibility spreadsheet" here: https://docs.google.com/a/firstpersonview.co.uk/spreadsheet/ccc?key=0AmVt8U67J0EWdHRkcXhqSjFja3VlcGRadUp1Sk5FM0E#gid=4

I'll put a message on our website warning about an incompatibility with DX8/DX18 and UHF systems.

Let me know how I can help with this.  It looks from the end of your video like the EzUHF is intact and working?

All the best

Simon

hi Simon,

thanks for the fast reply & your time for looking into this for me - appreciate it.

I think I may have to ditch the DX8, although would the DX8 effect the range, I only seem to get 500m then a failsafe?

Yeah the UHF was fine, not a scratch, nor a pulled cable or bent antenna! It worked perfectly on the post crash range test until I got to about crash distance & it did the exact same thing as in the air & wouldn't recover.

[Flyn]

Just had a second look at that video, it looks to me like the 2.4ghz board is still in, so powered up and therefore an active 2.4ghz antennas still in the circuit

Hi bud,

on the DX8 the PPM slave function wont work if the 2.4 board is active hence the tx needs to be unpowered to fly on PPM or you get nothing. I've not read anything about removing the 2.4 tx module. It's my understanding that if the power switch is on you get a powered 2.4 board & if the power switch is off & the PPM(trainer) plug is in you get an inactive 2.4 board & a PPM output only. I don't think it powers the 2.4 board once in trainer mode.

Although this may be wrong....

Here's screen-grab from the vid, power switch is off.

[Coyote]

Oh right I see, no your right there then, thought the radio was "On"

Same as with all these UHF units, they are always tested on Futaba ( you always get a futaba trainer plug with them. ) Shame, just more expense then

[Flyn]

 ;) no worries mate.

Anyone got a futaba 9c or 7 for sale??

[Flyn]

FPVlab thread:

http://fpvlab.com/forums/showthread.php?8088-Sad-to-say-EZUHF-Epic-Fail-amp-Crash-Vid

[Flyn]

Important update, post pasted from my FPVLab thread:

Just did the what you said - all is normal. rolled both sticks together no problem, all switches & dials are fine. RX light stays pretty constant, sometimes with a slow fade then bounce back to full but no loss.

Some progress though - it seems the DX8's trainer plug (with my current cable at least) isn't a constant enough connection for the EZUHF, if you move the S-vid to 3.5mm PPM cable even a little bit so the 3.5mm wiggles just a touch in the socket the EZUHF goes into a hunting failsafe mode as it seems very sensitive to the movement of the 3.5mm trainer plug & instantly thinks the PPM signal has been lost even though it hasn't. I reprogrammed the failsafe to full down elevator (from 30% up) and sure enough, hunting from neutral to full down instead of up.

I unplugged the cable & metered it for resistance & any internal shorts or breakages, permanent or intermittent non were found the cable is good. I then tried it on a second DX8 the EZUHF did the exact same thing on that DX8 too! I did find that if you stabilise the 3.5mm plug in the dx8 while you move the cable normal function is maintained but as soon as you let go of the plug & move/touch the cable & disturb the socket the EZUHF freaks out & goes into panic mode. Strange thing is though after a few seconds when the cable is stable the PPM signal is always regained with full control - this doesn't explain the total loss inflight today, as I'm sure I wasn't moving the cable all the time up to the crash!

Maybe I moved the cable just before it went out of range (if in fact I am having range issues too - that would suck!) & the RX never regained the then reestablished PPM stream from the DX8 to the UHF TX. Maybe the link was broken just at the wrong time - crashes are rarely just a single fault or mistake in the real world but more often a string of coincidences.

I'm going to make a fresh cable up tomorrow just to double check, if the DX8 had a futaba jack on the back instead of a 3.5mm one, or was hard-wired I bet you £100 it'd be fine! Would a DX8 ***edit - meant to say EZUHF firmware*** firmware update to desensitise the PPM steam detection a little help with this?? Would that even be possible without loosing functionality?

Could I mod my DX8 so it'd work??