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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Damn, I'm losing faith in this Frsky stuff. My mate and I both did range checks at the field and got between 40 and 50 paces.
In the air we both get the odd RSSI warning (set to 45) within 150m!
I read through the rcgroups "what's your frsky configuration and range". When everyone was using the D series receivers, every single thread talked about 2km ranges using stock antenna, no boosters. A couple years later the thread is still live and people are using the X series receivers. Most threads are now talking about people having low RSSI indication issues.
Options for me now are a 5dB antenna and/or D series receiver.
Brilliant, thanks for the info. I'm all set to do some more testing this afternoon before I dive in and purchase the antenna bits. I'm only racing my quad up to 150m away, so I'm expecting to have success with the stock antenna, otherwise something isn't right!
Last week, I was getting RSSI warnings less than 150m away. This week I have the soldered up RF board and better antenna placement, so I'm hoping for some improvement.
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.
I couldn't source SMA connectors and antennas,but I have found SMA-RP. Do these look like the right thing to get?
Is there a step by step instructions for factory reset the taranis??
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.
I've been considering fitting a connector for a 5dB antenna. I'll take a look on ebay to spy the bits.
I think one antenna up and one down, with the TX antenna up would probably work best for my FPV quad.
I'll experiment some more at the field when the weather improves.
I noticed, when grabbing an antenna during testing, the RSSI dropped quite a bit. I thought the other antenna was faulty, but after a while the RSSI came back up again so it must have switched to the other antenna.
How do I position both antennas vertical, but with planar separation? I thought you had to place them 90 degrees to each other to achieve that? do you mean one up, one down?
I fly with my TX antenna horizontal, due to;
a) this is best for LoS flying and I do a mix of LoS and FPV, so I want to keep the same,
b) I found in testing, I generally got better results with the antenna horizontal
c) With the TX vertical, you can't point it at your head with the Taranis, so when I'm sat down flying FPV, I'm normally leaning forward a bit, so the antenna would point forward more than it would up
d) prevents my Taranis from buzzing!
Obviously I have to make sure I'm not flying out to the side - that's the only downside.
So with a horizontal TX antenna, am I not best keeping both RX antennas horizontal in an L?
^That's the theory, but in practice during bench testing, I actually found I got better results with one antenna up and one horiz.
So I'm a little lost at the moment with the antenna placement :-(
I see what you're saying about both vertical though - if it blindly switches to the other antenna and its lower!! then I guess keep them both optimal - which is easier for a quad. Not so easy for a plane!
Well, after mounting the X4R back in the quad with the antennas in the usual position it actually failed the range test again. Re-orienting the antennas then passes easily (40 paces, 50 RSSI).
So I'll have to take back my test results I'm afraid.
I think I'll go ahead and try a firmware upgrade anyway.
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.
btw if Mike is still reading here, are prepared
to post some pics of your div rx antenna please?