Recently I have noticed a massive loss of range with one of my Frsky X8R receivers. I did all the usual things to try to resolve the issue, including trying a couple of other X8R's. I even tried one on it's own with no other devices connected, tried different environments, all to no avail. I went online and found that my problem is far from unusual, there appears to be masses of unhappy owners of these things, all having the same fault, so I decided to look a little further. I replaced the antenna's on the first bad receiver, and no improvement, but I did notice that none of my X8R receivers actually utilise diversity in half or full duplex, only one antenna (the same one on all RX's) actually does anything at all. This includes a brand new, out of the packet RX which kind of indicates possibly a bit of fakery is going on. Both antennas do connect to the RF chip, but from there who knows. A simple test is to grab each antenna, and watch your RSSI, one will cause a plummet into failsafe, the other nothing, no effect at all (my 3 did this anyway) Plotting my RSSI levels on a CRO showed a rolling swing of over 20db, in sync with RFH cycle, This combined with the other test of using a 2 watt full duplex rf booster offering an output gain of +14db and an input gain of +12db only yielded a 3db improvement in the rssi, and marginal (20mtr) increase in the now sub 100meter range, pointing more to a frequency problem, not a front end rf problem, despite no diversity. The only conclusion I can draw is that either the transmitter (Taranis) when in D16 (X8R) mode is missing frequency targets or conversely the receiver is, or the entire block is drifting off frequency and subsequently losing the link at one end of the spectrum, recovering again next time around, hence the sawtooth RSSI pattern. Most disconcerting was that after joining the FrSky forum, and laying out my discoveries as a possible cause for the piles of complaints, my posts and tests were quickly removed, and I have now been kicked off the forum by the administrator with no reason given.. no tears there, but in my book, it's quite telling about the company, no correspondence, just get rid of me before I cost them any sales. Anyway, I am also partly eliminating the Taranis from the cause list as my L9R receivers still get massive range, and my D8R-II also get the normal distances, it is only peculiar to the X8R, however, possibly contrary to that, it still may be a coding issue with the RF from the Taranis end, unique to binding that X8R RX, The thing that seems to possibly back that theory is that none of the complainants could get any of their X8R's to perform beyond about 20-100metres, and some with many receivers, others buying themselves a replacement. Doesn't stop there though, one victim tried a second Taranis but still showed no improvement. It almost seems like a virus infects both units. Mine lasted about one year before the first receiver died, and from then on none of my other X8R's would work either. Very strange problem, it's looking like my only solution is to completely ditch all of my $60.00 X8R's and for RC telemetry just use the D8R and for non telemetry the L9R. Big loss not having the S port direct though. I'd be interested to see if anyone else here has the same problem.
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I suppose the big question, is was this a bad initial load of firmware from FrSky, or was it a course of updating the firmware with several versions of OpenTX?
If you are convinced that this could not be an OpenTX issue, then I can only agree with you as I have not seen any problems yet, and it seems a lot of other people are also happy with their FrSky.
Thanks for sharing your info.
It seems you guys have determined that the root cause of this issue was that somehow the FrSky transmitter was messed up and a factory reset was required to solve it.
With this in mind, have you reported this to the OpenTX firmware team? Perhaps there is something that they should be aware of? It must be something that is affecting the specific transmitter protocol being used with these receivers.
Unfortunately, now that you 'fixed' the issue with a factory reset, the cause of the issue is now gone. So I suggest that if anyone else can reproduce this, that they report it to the OpenTX firmware team so that they can get to the root cause of the issue.
Hi Alasdair,
Thank you for the pics.
Just one further bit of info -
What is the distance from antennas outer-tip to outer-tip?
According to theory for 1/2Y it should be ~6.25cm.
I am going to use an 'L' thus ( | _ ) shape radius to be 1/4Y thus ~3.12cm
To see what RSSI I get at a fixed know distance.
I have been considering your Antenna installation, thus Vertical mounted,
also been thinking of Horizontal Mount.
I am going to do tests on my for my own interest to observe the RSSi variances
I am not flying the quad yet, just have it a fix distance ~50m with 3m elevation.
My tx will be handhold.
Thanks anyway for your effort in posting the pics.
Regards,
Gerhard
btw if Mike is still reading here, are prepared
to post some pics of your div rx antenna please?
Hi Alasdair,
Thank you for the info.
I am interested to see your antenna mount.
Mike, do you have any Antenna mount pics to share of your current build?
Thanks guys!
Once I have completed and sucessfully test my rig I will post some pics.
Regards,
Gerhard
Hi Alasdair,
I made some comments re diversity antennas on a reply to Mike.
Do you mind commenting on it too?
Thanks
Gerhard
Hi Mike,
It is indeed good news to read here that you have finally sucess with your x9d & x8r.
Well done with the perserverance!
I have a x9d+ & x8R
Building a Quad based on the tarot 650Sport frame with 4114 motors / 15" props etc.
Esc Xrotor 40A / 6S batt
FC : Pixhawk.
I am interested to know how you have mounted the rcvr 2x diversity antennas.
I have seen various pics etc. I notice that preferred mounting is in a vertical V-format, the V forming a 90o angle
with one another (the black plastic bits) normally facing to front or back.
It appears that the 'V-bits' is mounted at a variety of distances from
eachother. Reading tech-specs for diversity antenna mounts, using 1/2Y, the two antennas should be ~6.25cm apart,
or at 1/4Y, 3.125cm apart, in the same plane.
Since you have good results with your x8r rcvr antennas, could you post some nice detail
pics of how your mounted your antennas to share here?
Instead of the 'V' , why for instance not an 'L' or ' | | ' or '- -'
This subject has probably been flogged to death elsewhere, but since I am following this thread, it would be nice if guys can post pics
of how they mount their diversity antennas.
Maybe Alasdair can comment here and help a newby here with his knowledge and practical know-how?
Lastly, why is a excellent/reliable/good/avg/poor/ RSSI level?
Thanks all for the interesting info shared here.
Regards,
Gerhard
Reading technical specs etc re div antenna mo
Hi Mike, Alasdair,
I have been following this thread for some time, since
I recently bought a x9d+ with the x8r and thus my interest here to understand
whether I bought toy-grade stuff or what?
Interesting technical info and the like, thank you.
Following Alasdair & Mike's initial problems and the final solution, for Mike, (firmware reset/upgrade etc) it appears
to me that the x9d+ and x8r combo seems to have excellent results for Mike.
So, what do you say now Mike, Alasdair, are the x8r good to go, relyable and still a good choice?
I ask this, because the spirit of discussions on this thread is that the x8r, x9d+ is rather 'toy-grade' thrash.
Now, with Mikes' solution and final results, it appears the the combo is in fact quite good', if not excellent.
Thanks anyway for making us all be aware of various factors that, in general, for RF, one should look-out for?
Your comments?
gG
@Mike sky : have you setup custom LUA script before you reinstall opentx ?
Hi, thansk for answer :
-> follow to your comments here, I make a complete reinstall
- bootloader
- xjt
- x8r firmware
I was using custom LUA script for Radar mod (with APM) and I expected suddently lose of range, one day, without doing anything special. 2 flight very good and after that, on the fields, at 10m it goes in failsafe and no more range since this day.
I will see if it's change with new firmware 2.1.3 (old was 2.0.17) but I sceptical about this...
Hi Mike,
I am interested to see how you have mounted/installed your diveristy rx antennas.
Can you post some pics?
Thank you.
Regards,
Gerhard
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