Hi Mike,
Regarding my 'loss of bind' problem:
A thought occurred to me that maybe I overlooked before - on the 9XRPro, is the PB14 mod also required before the Double Rate option will work or can they be used separately? Since the QX7 already has the PB14 Heartbeat equivalent by default and you are now providing the Double Rate mode as an option there, I guess the answer is no??
Anyway, I've gathered more empirical data for you, but I'm now not sure what steps to take next. I'll write down everything I've noted today and try to make it as clear as possible. My apologies, in advance, for being so verbose and long-winded, but I do not have concrete, numbers- and letters-type, data yet, so descriptive text is necessary, I believe. I had initially set up my video camera and tripod to film for you, but decided that describing those videos was probably no more benefit than writing this text, so I'll try to break it up into related and digestible chunks
What I guess I'm looking for next is some guidance from you as to what tests or experiments I can try to gather more meaningful information.
This is where I am up to -- I flew five planes today (total of about 8-9 flights, then the wind came up too strong) using my QX7, which has an Orange DSMx module in the external bay, as noted earlier. Four of those planes were using the internal FrSky XJT module communicating with 4x FrSky S6Rs, one used the external DSMx module communicating with a genuine Spektrum Rx brick. During that time, I detected no noticeable loss of bind/communication or erroneous behaviour though, in light of what I saw later in the day at my workshop, it is possible that minor instances, without catastrophe, might have been occurring (see later notes).
I came home and later started to try to reproduce the 'loss of bind/comms' phenomena. In that, I succeeded, with both the 9XRPro AND the QX7 both experiencing the events but, given that I used the QX7 successfully during the morning, I am not sure why I can now reproduce the fault at home on one of the planes I flew (once) successfully this morning -- a bit of a pattern emerged, but nothing 100% clearly predictable yet, though close.
Before I describe the failure mode again (previously provided in an earlier post), let me clear up some background information. To try to eliminate environmental issues as a possible cause, I performed this series of these tests inside my workshop (which is, for the moment, a 7mx3.5m metal shed, roller door opened at one end, with metal roof but with the rafters stuffed with EPO and balsa models) and also outside my workshop, in the open air. I performed some tests with my mobile phone switched off and also a local Wi-Fi access point (2.4GHz, I believe) turned off. Testing while inside the shed, outside the shed, with phone on or off, with Wi-Fi on or off, seemed to make no difference - I still lost bind/comms on occasions and the frequency and duration of the loss didn't seem to vary with those changes in environmental conditions.
Now, some detail of my radio/Rx environment this afternoon. First, the Rxs, as that's easiest to describe. On my B17, I have an FrSky S8R with antenna passed through a tube in the fuse to the outside world and taped to the underside of the fuse at 90deg to each other. On an AXN Floater (small powered glider) I use an FrSky X4R, again with antenna passed out through the fuse and taped outside at 90deg to each other. On both planes, however, today I left off the canopy to be able to watch the bind LED. I also used a Spitfire with S6R, again with canopy off and antenna exposed, which had been flown once this morning with the QX7 internal module.
EDIT: For each of the tests, I was standing no less than a metre away, often 2 metres and sometimes 3 metres - if necessary, tomorrow I can retry some testing from about 10 metres away, if you think it will make a difference (vis-à-vis swamping of the signal).
Failures (each in a similar manner) occurred with each of the S6R, S8R and the X4R (I'll describe the failure mode(s) in a moment), though I have to say that the S6R and S8R seemed more prone to fail more often and sooner than the X4R (which still experienced failures, but not as much).
Both the 9XRPro and the QX7, which were each tested against each of the three Rx units once they were bound to each of the Txs, experienced failures though, without a doubt, the 9XRPro experienced failures more often and more quickly than the QX7 - as much as 5x-10x more often with the 9XRPro as the QX7. Further, with the QX7, the External DSMx module was disabled and, sometimes physically removed. The presence of the Orange DSMx module (even disabled) seemed to make almost no difference though, if pressed, I might say that removing it made the QX7 slightly less prone to bind failure but I couldn't quantify it. With the 9XRPro, at no time did I enable the PB14 Heartbeat option, as I have not yet made the required hardware mod.
All three of the Rx -- S6R, S8R and X4R - experienced failures. This surprised me, in light of your earlier test on an X8R, so I placed extra tests on the X4R - it DOES fail, though more with the 9XRPro than the QX7. The worst combination seems to be the 9XRPro with an FrSky S6R or S8R.
To trigger a failure, the only stimulus I needed was to tick the enable box for Double Rate and exercise the control surfaces. A partial degradation or a full loss of bind will occur within 15-20 seconds, often instantaneously. To make the failure go away, sometimes it was as simple as unticking the box. However, on more than half the occasions, it was necessary to power cycle the Tx (but never the Rxs) to regain a bind. I'm not sure what other less-intrusive recovery methods work, yet.
The failure events seemed to fall into one (or, progressively, all) of three levels of observable severity:
1. A slight flickering of the Green bind light with no apparent impact on control surfaces being constantly and actively (even aggressively) exercised at the time but no report from the radio of poor RSSI (it's possible I had this today at the field and didn't notice it, hence the reason to leave the canopies off later today and watch the bind LED)
2. A constant flickering/flashing of the Green bind LED and occasional stuttering of control surfaces being constantly and actively exercised at the time and an occasional though infrequent report from the radio of poor RSSI
3. A complete loss of the Green bind LED (Red was apparent), complete loss of control surface movement and report from the radio of no telemetry and loss of radio signal
On most occasions, the failure would progress from Level 1. to Level 3. with time (over 10-15 seconds) but on many occasions, the Rx would go straight to '3' - full loss of bind even as I was lifting my finger from the MENU button from ticking the Double Rate box. On a small number of occasions, immediately unticking the Double Rate box re-established bind, but this did not happen often - in the majority of times, a power cycle of the radio was required.
I do understand that you have said that you tested it at your end and have not had a failure. However, while I cannot yet predict how quickly I can cause a failure nor how severe it will be, I can reliably say that I will see a failure, on these two radios (though, more often on the 9XRro) and with these three Rxs (again, the 'S' series MIGHT be more susceptible, but I don't think I'm ready to sign to that yet).
At this point, I am not sure what steps to take next, though a 'sleep on it' might bring new ideas.
Maybe you can make some suggestions.
regards,
ozphoenix
MikeB wrote: ↑Sat Jan 05, 2019 10:15 pm
I've tested doublerate and PB14 sync. on my 9XR-PRO and it all works OK. Tested using an external XJT module.
To connect PB14, you need to add a wire from the pin second from the top in the module bay to the unused place (pin 2) on J2 (10 way-connector on the right when looking at the board from the back of the radio.
When you have PB14 connected and enabled, you get a tick mark at the right of the display beside the PB14 check box when the protocol data is synchronised with the heartbeat.
Mike
I had bought the plane used and didn't notice that the ESC was set to 'cut power on LVC' 
