Expected analogue FPV range

Hi Nidge, I have a Radiomaster TX16S and am using a Frsky XM+ receiver that is stock on the quad.

I’m 6’ and been standing up and even attempting to head track - to no avail.



Re watch that DVR footage you posted and pay attention to your RSSI value. That doesn’t look right to me. With XM+ I would expect it to start at 99 as you arm then slowly drop down in numbers as the quad moves further away from your radio. Your RSSI value looks sporadic and is extremely low. Check the connector of the XM+ receiver is connected firmly into the socket on the flight controller.

I thought, wrongly, he was using CF as it was labelled as LQ.
Which strengthens my theory that it’s an interference issue with FrSky.


I brought the exact same BNF with the XM+ receiver. And looking at the photo from his previous topic he had RX antennas configured exactly the same as mine and I didn’t have any issues with interference although I did only fly 4 packs on it before upgrading it to Crossfire lol

Maybe that’s why the LQ isn’t reading right because LQ is a crossfire specific telemetry value. Guess he needs to select the RSSI element for the OSD instead of the LQ?

Yeah, pretty much not a happy bunny atm. I spoke to UK seller who told me to take it up with iFlight - not exactly how customer support is supposed to work. :face_with_raised_eyebrow:

iFlight have offered to send a new VTX, however I swapped the VTX out for a brand new AKK Race Ranger this weekend and it’s still far from brilliant so I am not convinced is a simple issue with the VTX. I’ve now ordered a different receiver so I can eliminate that from the equation. Tbh I’m pissed that it’s been left to me to sort out. I’ve tested the googles on a completely different set up and they’re fine, no issues at all. @DeanoG60 - If you do get a chance to post some video I’d love to see it to do a comparison.



1 Like

Will post some as soon as I fly again (damn weather and xmas! Lol)

For some reason my DVR has been cutting off as soon as I take off. I think it’s due to the fact I’ve got my pit mode switch setup on my arm switch so when it arms it ramps up the VTX power and I think this is cutting the DVR off so I will get it sorted and post some DVR as soon as the weather let’s me fly again (could be waiting a while lol)

I wonder if your GPS is interfering with the signal :thinking: mine didn’t come with GPS but it is in the post as I’ve ordered one from banggood :+1:t2:

I have a dvr of your flight if you want me to put it up? Only recorded on my rd200 though

1 Like

Yeah can do at least it will give him an idea of the quality.


Interesting, I don’t recall seeing any breakup actually in the goggles while I was flying, but I guess I could of just missed it because I was concentrating or it’s just the DVR as that’s always lower quality than what you actually see lol

Think that was only my 2nd time I’d ever flown a 5" quad so was concentrating pretty hard lol

The RSSI is reading 0 because I hadn’t discovered sensors for the telemetry.

This was flown on the stock XM+ RX I’ve since upgraded to crossfire.

The breakup is probably due to my rd200. It’s only got a dipole antenna. I usually plug it into my goggles av out, but didn’t this time

I’ll try and get my DVR working next time I fly. Hopefully if the weather is good this saturday :crossed_fingers:t2:

1 Like

I’ve watched your DVR footage again while paying attention to the breakup and I’m now 99.9% convinced it is interference, possibly caused by a switching regulator. Even as you take off it’s possible to see very repetitive pulse noise in the video.

Somethings I would try.

Power-up the quad but not the transmitter/controller. Then while viewing in the goggles either have a friend walk away with the quad or you walk away from the quad (try not to fall over) and see if the break-up still exists. If it does then you have interference being generated on the quad which is making its way into the video feed.

If the video is clear do the same test but this time with the quad bound to the TX. DON’T ARM IT. If you have interference then this is coming from your controller and making it’s way into your goggles.

Lastly place the quad a distance from you but make sure you have a clear video signal. Arm the quad and fly back to yourself. If you have interference then the source is probably coming from your ESC’s and making it’s way into the video feed from the camera to the VTX.

Nowadays the battery input usually has an electrolytic capacitor across it. The purpose of this is to smooth out transients than can appear on the main power bus. ESC’s will be similarly patched with a capacitor. It’s not that uncommon for one of these capacitors to go open circuit especially if the manufacturer has skimped and used a value of capacitor lower than that of the expected voltage it is to work with.



Hi Nidge, magic - many thanks for detailed ideas, really appreciated. Am hoping to pop out at lunchtime to test a couple of packs with the new VTX and see how it’s looking. I’ve also ordered a new RX so I can isolate that as a potential issue too.

Seriously - thanks chap, I just wanna get this sorted so I can go fly!



Hopefully you get it sorted pal :crossed_fingers:t2:

Where did you purchase the quad from? And what was the customer service like at iFlight?

I’m not going to name supplier publicly yet, I’ll give them a chance to sort this out as their first response was less than impressive. iFlight were swift and offered a new VTX, I’ve gone back and said I’m not convinced that it’s that straightforward and I’ll go back to them as soon as I’ve done some more tests.

All a bit of a PITA tbh, whichever way it goes I’d be waiting several weeks for either supplier or iFlight to sort this out so I’m probably going to just have to sort it myself.

Question - if it’s noise on the ESCs or power rails somewhere, will taking the camera power off the FC and running it directly from the VTX power pins help here?



Vtx’s normally come with a dedicated filtered 5v supply for a camera. Some fc’s have it too. Definitely use that supply for the camera. But I wouldn’t put it on the vtx main power pins.

1 Like

Yeah - meant the filtered supply. I managed to get out and test at lunchtime - video to follow shortly!

1 Like

So… a massive improvement with a new VTX, I also put another set of vinyl nuts between FC and main ESC board to try to give it all a bit of breathing room. There is clearly still some interference so not sure if this is more likely RX interference or EM interference… but I’ll keep experimenting! There is also a known issue with the OSD using the SmartAudio on the Race Ranger, it kinda works but it’s out of synch. There is a fix for it though - something else to sort out next!


1 Like