V303 / x380 Stock Receiver Swap + Taranis x9D Build Log (video)

I wanted to make it possible to use my Taranis x9D with my v303 (x380 hybrid) for various reasons.  One of them being the ability to have RSSI to the minimOSD, which I haven’t gotten to work with so far with the stock Flight Controller (FC).  I also wanted to have both the x380 and Twinstar II on the same radio as models for simplification.  I was also hoping for more range than the stock radio, though in recent days I’ve read of stories of people at least with the true-blue x380 hitting 2 miles in one direction on the stock equipment.  In this build guide I’ll share the details of what I end up doing.

I started off by using the FrSky D4R-II receiver.  I ran some basic tests to try to determine if the range was good enough.  I did the Taranis Range check, which sets power at 1/30th the original.  From research it appears you should be able to achieve no signal loss out to around 98 foot if everything is ok, though some say  make it 30 paces without going below 43 and all is ok (38 is loss of signal, 43ish is critical).  Furthermore, I was concerned that my distance checks I did outside of the range check, showed values of say 70 at 100 feet and 60 at 400 feet and this may have actually been ok.  Its been suggested that the RSSI values dont tend to drop off as sharply after some distances, so its not uncommon to see 43-55 for instance at much longer distances.

I wanted to confirm all this is the case and also heard that the D8R-XP had better range.  So thats the other part of this experiment, checking its range.  I may also consider getting an EzUHF 8 channel Lite, which I also use with great success on my Twinstar II.

Taranis x9D + V303 (x380) Settings Discovered

Before jumping back to the receiver portion of all this, first we take a look at the Transmitter settings.  It was a bit difficult getting things to work at first.  But in the end I managed to get all the functions working.  Here are the screens I ended up with:1-modelsetup1







8-curve1headless 9-curve3fap



Here is a video I made showing the transmitter testing via ground station as well as some amp pull testing on the motors with stock vs x9D

Success with the D4R-II and Taranis x9D but not with EzUHF

Since beginning this article I did get everything working with the Taranis and the D4r-II.  The only challenge so far has been getting used to re-centering the throttle stick, but having it beep on center comes in handy.

As an aside, I spent days trying to get the EZUHF working with the quad.  I tried two different EZUHF’s.. one was already bound to my transmitter for the Twinstar II, so I used that to rule out a binding issue.  I even tried a PPM converter to try to make the PPM signal more “compatible” with the v303 quad but that did not help.  I tried changing Ezuhf settings on the Taranis, ranging from the MS setting to other settings, but nothing worked.  So I gave up on that idea and have settled for the D4R-II.  Now i’m trying to get the D4R-II’s RSSI output to work with the V303/X380 and the Micro Minim OSD Mod.

RSSI Output from D4R-II to Micro MinimOSD Trials and Tribulations

Right now I’m in the midst of getting RSSI smoothed out with the Micro MinimOSD mod.

It seems that for the Micro MinimOSD to work and be able to recognize the signal sent from the PPM #2 pin out of the D4R-II, it needs to be an analog signal.  The cable coming out of Pin #2 either way, outputs around 3.20 according to my multimeter.  After reading various posts online I found that I could make an RC Filter for the RSSI portion using a 10uf Capacitor such as this in conjunction with a 1k Resistor like this one.

Below is a diagram of the wiring.. I started off without the extra ground, but now I have it in play, unsure if it made a difference or not, as I still get a voltage reading with just the one side with a ground.


The first time I tried this I had the RSSI going in the wrong pin location on the D4R-II as in this photo below, but highlighted is where I now have the RSSI and ground connected (basically the first pin on the end under the main connection and the ground being the third one over on that second row):


Here is the final position of the receiver in the quad.

20160528_145856 closeup of receiver with wires for rssi underweb

20160528_145849 rssi before double negative with quadweb

So once I had everything wired up, I tested the RSSI readings with the MinimOSD.  I ended up with a “close” working reading by using the values in the image below.

closeRSSIwithcapresistorsWEBI believe the key here is setting the Maximum value AND the minimim as well.  The max defaults to 1023, in the pic above I ended up trying 853.  With this setting, when the Transmitter is close, the TX itself reads around 79-85, while the OSD shows something around 79.  However, if i switch to range mode and walk away, when the TX shows 49, the OSD is still showing something around 69.  I am thinking if i tweak the lower limits it may help smooth this out and become more accurate.

If all this doesn’t work, Ill just live with the inaccuracy for now and continue relying on the Taranis beep when it reaches 43.

I have another video in the works for this part.  I’ll update this once its completed.


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