FrSky not so free.

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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    • great news!!

      did you upgrade the only the openTX firmware, or the XJT module too?

      • Before all of this I had upgraded from OpenTX 2.0.15 to OpenTX 2.0.17

        without a total wipe etc.

        So i never thought it would have something to do with it

        so i took Alasdair advice and did a total factory reset with frsly firmware and did a clean upgrade to the new opentx 2.1.3 firmware i must say this new firmware is very clean in the telemetry screen and for me it works pefrectly even without the lua scritps that i used before but i don´t need them now.

        the only thing i did now was the total reflash of the latest opentx firmware from a clean radio.

        regading the xjt external and x8r and internal i had allready flashed them with the EU firmware

        but still had RSSI problems.

        Today i will go out and do some more packs this time with the internal xjt and see if it also has nomore RSSI warnings.

        i hope this solved my problem and hope it will help others.

        this firmware is like a shoot and go kind of thing it will either work or not.

        one this is certain if it works don´t mess it with upgrading bla bla it will only get you pulling out your hair.!!

        believe me!

        If your system is working without any issues leave it be!!!

        if you have the same issues as me try this it can work or not!...

        open source its hard when not working but fun when is!

        come back later with internal xjt results.

        OpenTX 2.0.15
        • i can clearly say in my case problem solved

          I took it out to 1.2km without one rssi warning 

          brought back due to lossing FPV image i don´t plan to take it out so far

          just did it to check the RSSI.

          so for me its back to enjoying flying without the anoying RSSI warning.

          hope this will help others fix there RSSI problems

          in my case it did the trick thanks Alasdair

          Still i believe there is allot of improvement needed from Frsky

          although  i never went below 40db there was allot of jumping of the RSSI readings.

  • Bad weather to test out more with fresh packs...

    I gave your tip some serious thought and decided to do a total refresh update of the firmware of the Taranis x9d plus and went ahead and did it to the latest one 2.1.3

    The telemetry menu looks very cleaner now. so I will try out the re flash and see if it helped.

    as soon as the good weather comes back I will let you know how it went

    and with some luck maybe the problem was on the firmware all this time or not.

  • Hi Alasdair,

    I have been puzzled for some time :)

    Frsky you love it for the telemetry features and hate it for this RSSI,

    I flew yesterday without any power and connections to the receiver coming from the gimbal FPV connections etc. I disconnected them totally as to eliminate possible interference from the FPV and gimbal and landing skid

    I just flew with the FC & receiver and voltage sensor connected.

    not even my mobile phone was with me

    the only thing I have not changed was the NAZA V2 FC which I doubt causes this and the radio itself...

    I have tried two X8R receivers and the same issue

    last thing to try would be another taranis radio..

    running out of options to try.

    ah I even have the receiver attached to a 3d print plate which is about 10cm out of the drone

    I have placed the antennas away from the carbon fiber booms where I have ESC inside them

    I placed them on the body shell at 90ª to each other

    there has to been something but what....

    XJT Module helped increase the range but not close to the normal standards that people have.

    I did a range check and walked away 64 steps until it went red.

    better than the 18steps I got with the internal XJT.

    Today I will do some more flying at a different location in the country side always away from radio interference and populated areas.

    and I will even disconnect the voltage sensor and fly only with FC connected to the sbus port of the receiver nothing else connected to the receiver.

    .

  • Wow Alasdair,

    What a explanation! I see that you dig deep on it. I'm currently at work, but very anxious to get home and look at the board to follow close your explanations. I don't have the low range problem, but connection the pin1 of cc2500 to 21 of 2431L could be a potential upgrade to turn on the LMA ( am I get it right? )

    Yesterday after posting I have tested again the diversity, now with TX attenuator on (range test) and by a glimpse I saw the RX level dropping by 15 points ( rssi scale ) when I covered the 'uneffective antenna'. So , it is not easy to reproduce, but sometimes the signal drops. It could be coincidence or interference, but maybe somehow something is controlling the 2431 rf switch;

    I'll try to analyse the rf switch pin with an oscilloscope while playing with the antennas to see if it is really dead or if its  active sometimes.

    I'll post later ! Thanks again

    • well today good weather and did one pack testing the XJT Module

      In my last post forgot to mention I am using a 3s 2650 lipo pack on the taranis plus

      so the good news got to 800m with rssi around the 60 & 70  and then constant RSSI warnings

      bad news getting to the 800m mark I got a bout 3 or 4 rssi warinings on one time it was zero for about 3s

      its better than before were at 100m out I would get constant RSSI warning and even zero for a few seconds

      Maybe the external modulo gets more power..

      so did it help and improve with the xjt module for sure it did.

      do I feel more confident for close flying yes but more than that forget it.

      and what bugs me is the RSSI warnings...

      so i might really ditch this Telemetry X8R nonsense from frsky and go Immersionrc way

      what a bummer really was hoping for a better result today.

      Alasdair I thank you again for your vital and informative posts.

      during the next days i will do some more flying and see from there

      only one pack today is not enough testing but it gave me some hope little but some :)

  • Thing is people can't separate Frsky and OpentX in their mind. Frsky gear isn't that special once you take away the opentx side of things. just cheap to buy.

  • Hello Alasdair

    I own an D8R2-plus / DJT combo and , despite not having any range issue, I could verify the diversity problem in my setup.

    Did you went further on it? Do you think it is not diversity at all? I have post a message on their forum asking for explanations.

    If anyone could analyse the board and find out if it is an failing board or a project flaw it would be great.

    My post : http://www.frsky-rc.com/BBS/viewtopic.php?f=4&t=7194&sid=9c...

    Regards,

  • Some of us flying gliders have similar problems with the frsky equipment with the new X9e and taranis plus. Range is somewhat limited. So far we only get denials from the distributor (t9 hobbysport) and no word at all from Frsky.

    At this point I have lost all confidence in Frsky and the retailer.  This "cheap" system becomes very expensive when you start loosing models. 

    It's very telling that Alasdair got kicked off the frsky forum.

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