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Quick Connect "Feature"

Old 01-26-2008, 09:34 PM
  #26  
1bwana1
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Default RE: Quick Connect "Feature"

KC36330,
In the case of 2.4 MHz systems, turning off the TX is not a good test of a loss of signal. When you turn off the TX the handshake between the TX and RX is lost. This handshake includes the two frequencies on the 2.4MHz band that the RX/TX have agreed to communicate on. So when you cycle the TX, this step must be re-done. This is what takes so long. The real change in what the Quick Connect feature does is to eliminate this step when the RX is re-booted. In the old RX design, the two frequencies that the TX was broadcasting on was lost during a "brown out". The RXs with the Quick Connect Feature memorize these two frequencies, and so are able to re-establish communication instantly after the re-boot. Usually much less than 1/2 second.

In order to properly test a loss of radio communication that simulates a loss of signal in a real flight situation you cannot cycle the TX. You need to block the signal between the TX and RX. Since the 2.4MHz band does not penetrate water very well, you can find a way to put a water barrier between the TX and RX, and then remove it quickly. You will see that it reconnects instantly when the barrier is removed. In flight, if something blocks your signal, your radio will reconnect instantly when the RX can "see" the TX again.

I hope I was clear in my explanation. Feel free to ask questions.
Old 01-26-2008, 09:56 PM
  #27  
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Default RE: Quick Connect "Feature"


ORIGINAL: 1bwana1

you can find a way to put a water barrier between the TX and RX, and then remove it quickly.

It just so happens my other more expensive then my turbines hobby is reef aquariums............i put the RX at the end of two side by side 75g tanks (they are 4' long each so an 8' x 18" x 18" wall of water) and i couldn't get it to loose signal, that's 8 feet of water between the TX antenna and the RX with the module button pushed in, so it must take one hell of a bunch of water, I've got a 180g setup too but it's currently sitting here empty []

i guess it has to come down to fly it and see what happens. Ole collectivepitch there installed in it his avistar and when i took it to above 600 feet of altitude it went into fail safe and it took several seconds and a drop in altitude to get control back, he called up Horizon and they recommended a few changes and the next flight when he was flying it few off about 1/2 mile away and crashed with no control at all. without any question, Horizon replaced the RX and tweaked his module, now I've got it in an electric Funtana for testing as it's a little cheaper to crash and he's down to only one plan to fly and won't chance the Spektrum again.

weather permitting tomorrow we'll see how high we can go before loss of signal again.
Old 01-26-2008, 10:14 PM
  #28  
1bwana1
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Default RE: Quick Connect "Feature"

My guess is that it didn't go through the water, but was able to recieve a bounced signal since you are doing the test in doors.

I would love to see a picture of the RX install, it might help debug the problem. I regularly fly much further than what you are reporting with no problems. A guy at my local field a couple of weeks ago was having problems similar to yours. When i looked inside the plane, his wires were a rats nest, and his RX and antennas were touching the servo wires. I cleaned up the install and the problems went away.
Old 01-26-2008, 10:29 PM
  #29  
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Default RE: Quick Connect "Feature"

Main RX is mounted to the left fuselage side with the antennas pointing lateral:




Remote RX is mounted 6" back from the main RX under the canopy with antennas longitudinal:



no birdnests in here bud

Old 01-26-2008, 11:04 PM
  #30  
1bwana1
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Default RE: Quick Connect "Feature"

KC36330,
I agree it looks like a good install. Nice work! The only improvement I can think of at this point is to have one antenna on each of the RXs horizontal as you have them now, and the other at 90 degrees. I looked back over the thread and was unable to determine if you had a problem with this plane or not.

Do a real good range check.

1.) With the plane level on the ground, walk about 100 ft away with the TX range button pressed. Have someone rotate the plane though 360 degrees. Make sure he doesn't get between the RX and the TX. I usually pause about 16 times through the rotation and check all the controls.

2.) Next do a vertical rotation. have your helper stand the plane on it's spinner, and spin the plane 360 degrees, again stopping about 16 times through the rotation, and making sure he never blocks the RX from the TX.

This method has proved very reliable for me. I am normally doing this on 35% + so I use the Flight log tool when doing this so I can see what each RX is doing, and optimise the RX positions. I realize that the RX you are using does not allow this. My feeling is that if you get a good range check this way, you will be OK. The only other thing you have to watch out for will be the low voltage issue. I am assuming these RX have been upgraded. What motor, battery, BEC,Sevo, RX power setup is in the plane?

One more thing, when flying use the swivel on the TX antenna to be sure that the antenna is never pointing directly at the plane. There is a null emanating from the tip. The strongest signal is from the sides of the antenna just like on a 72MHz system.

Let us know how the flight goes.
Old 01-26-2008, 11:06 PM
  #31  
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Default RE: Quick Connect "Feature"

Okay, let's cover this again. The new RX's are NOT supposed to re-establish quickly when the TX is turned off and on again, it's for when there's a glitch or brown-out onboard. You test that by disconnecting that or turning the switch off and on again on the PLANE or RX, not the TX.

The TX and the RX ALREADY had an agreement and had chosen channels. What YOU are doing is forcing them to re-choose channels again, which IS NOT NECESSARY. The new RX's are designed to remember that agreement for a quick re-connect in the event of an onboard short or brown-out. You can't just decide what it is and what isn't doing according to YOU, just because you want to create something to panic about.

Electronics go by a very critical set of protocols, particularly digital transmissions.

Got it?

Jim
Old 01-26-2008, 11:11 PM
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Default RE: Quick Connect "Feature"

Jim,
Go easy, I think he understands that now. We all have a lot to learn about this new technology. Let's just try and help him be successful with it. As we know, it works great.
Old 01-26-2008, 11:21 PM
  #33  
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Default RE: Quick Connect "Feature"

ahh it's ok, Jim can't get his head far enough out of his ***** to not be a *****. it's quiet clear to me that when collectivepitch's original setup was failing at altitude it was NOT becase of a brown out or a short at the RX it was becase of a lack of TX signal.
Old 01-27-2008, 03:28 PM
  #34  
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Default RE: Quick Connect "Feature"

I don't see why a similar sort of routine wouldn't work just as well with the TX -- there's extra processing for alternate threads of execution available when the TX is operating, obviously, otherwise updates to the LCD would not be possible. Why not write the current tx pair and timestamp into some form of nonvolatile memory every second or so (some form of memory that does not deteriorate due to read/write/erase wear) and IF the tx was off for less than some certain interval (based on querying this info on startup), quickly check for RF activity on that pair and if it's unused, then start transmitting immediately on those freqs. You could probably even do it without the timestamp, simply always starting your frequency choice from the last used pair when scanning for open frequencies. In that case, you would neither need to write the timestamp nor do it so frequently -- once each time you start up and choose free freqs to use would be enough.
Old 01-27-2008, 03:55 PM
  #35  
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Default RE: Quick Connect "Feature"

eajohnson,
You're overthinking it. The problem is almost always with the RX, so why change anything on the TX? As far as the TX goes, if it's losing the model it needs to be repaired, because it should be consistently talking to the RX. You're mentally adding things that don't become problems for like 8 steps down the line. The TX and the RX have an agreement going on having a channel and a backup before it ever starts rolling out. Shorts in the plane, a long-time ongoing problem, cause the RX's to lose the TX for a second, and they added another safety for that which DOES remember the last agreement. Any longer than that and you're likely to be taking home the ol' Bag-O'-Balsa anyway. If it starts hitching and glitching, any decently trained pilot knows to get it on the deck, slow it down and land it just as SOON as you can do it.
Sorry to sound testy before. I had a migraine. Not an excuse, just the explanation for it.
Jim
Old 01-27-2008, 09:11 PM
  #36  
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Default RE: Quick Connect "Feature"

KC36330,
How did the range test and flight tests go today?
Old 01-27-2008, 09:22 PM
  #37  
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Default RE: Quick Connect "Feature"

he flew his jet today. it was to windy for the eletric plane.

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