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Realistic range with QX7 + X4R-SB? (180m with current configuration)
#1
I recently built my first FPV quad and not knowing what to expect WRT range, I need some feedback. 

Equipment:
 
FrSky Taranis Q X7
FrSky X4RSB
Foxeer TM25 Switcher
Emax Pagoda II antennas on both ends
ZMR250 frame
X-Racer F3 v3.1
etc.

Scenario 1: 

- RX Antennas at about 90 degrees. 
- VTX @ 25mw 
- Both RX and VTX antennas mounted to the rear of the frame

At about 100m (LOS) I start getting some video breakup, but no RSSI warnings.


Scenario 2: 

- RX Antennas at about 90 degrees. 
- VTX @ 200mw 
- Both RX and VTX antennas mounted to the rear of the frame {see attached photo}

At about 100m (LOS) my video is rock solid, but I start getting low RSSI warnings from the Taranis. 

Scenario 1 + 2 led me to believe that at 200mw the VTX caused some interference and that the antennas might be too close to each other. I then moved the RX antennas to the front and made sure my VTX antenna in no way grounds on the frame. 

Scenario 3: 

- RX Antennas at 90 degrees. 
- VTX @ 200mw 
- RX antennas on front of frame, VTX antenna at rear of frame. 

With these changes I managed to get 180m before I started getting RSSI warnings (LOS). Video performance is solid. 

When doing a range test on the Taranis, with both my VTX on and off, I get about 6 meters range before I start getting RSSI warnings from my TX, so I believe the VTX + RX issue is resolved. 

So now my question. Is 180m a realistic range figure and what can I do to improve this? 

   
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#2
I have a very similar antenna setup on two of my craft and I can get out to 200 meters on 100mw VTX with 80+ RSSI.  I think there might be a a little more spacing between my VTX antenna and the RX antenna guide on mine.  Maybe check to see if you have an antenna that has come loose?

[Image: qruwrkcl.jpg]

Also, I have noted that some places I fly must have RF interference from some source and even in the clear I get signal alarms and closer ranges.
SoCal Kaity :D
OMG, no one told me it would be this much fun!  Addicted :)
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#3
Wouldn't worry too much about the RSSI warnings, Taranis defaults are set pretty high. But something is definitely up, as you should a range more up around 1000-1500m.
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#4
Your radio range is definitely a bit worrying. If you are flying at open field, I would expect at least 1KM range before evening getting RSSI warning.

Video range can be significantly affected by your VRX antenna too, with 25mW and diversity setup with some directional antenna, I was able to go 800m.

I don't think interference is the cause here, because you start getting RSSI warning at 6m without VTX powered on when doing range check, ideally you should be able to go as far as 30m-40m or more.

Make sure the antenna on your Taranis points upward, and not pointing directly at the model (power will be the weakest if you do this), try this and let us know!
Don't be a LOS'er, be an FPV'er :)  My Gear - Facebook - Instagram - Twitter
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#5
(08-Jan-2018, 03:46 PM)Oscar Wrote: Your radio range is definitely a bit worrying. If you are flying at open field, I would expect at least 1KM range before evening getting RSSI warning.

Video range can be significantly affected by your VRX antenna too, with 25mW and diversity setup with some directional antenna, I was able to go 800m.

I don't think interference is the cause here, because you start getting RSSI warning at 6m without VTX powered on when doing range check, ideally you should be able to go as far as 30m-40m or more.

Make sure the antenna on your Taranis points upward, and not pointing directly at the model (power will be the weakest if you do this), try this and let us know!

With regards to video performance, I am aware that I do not have a great setup. I'm currently using the Eachine EV800 (no diversity) and hope to be able to upgrade soon. I purchased the EV800 as "proof of concept" when starting this hobby. What concerns me most at the moment is my RX TX range. 

I just ran a test (with VTX powered) and these are my findings: 

Taranis Range Test: 

1m - quad facing away from me: 64
1m - quad facing towards me: 79

6m - quad facing away from me: 39
6m - quad facing towards me: 45

Telemetry RSSI readings: 

1m - quad facing away from me: 77
1m - quad facing towards me: 81

Changing the TX antenna orientation make single digit differences. I tried horizontal, 45 degree and vertical antenna positions. TX voltage currently at 7.5v (not sure that makes any difference). 

Photo of current antenna configuration attached. 

   
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#6
Looking at your antenna positions, they look to be clear of anything that would rob signal. Do you have another set of antenna you can mount to it? Starting to wonder if there is not an issue with one (or both) of them. When my quad is close to me, a meter or less, I oft see low numbers and even have critical alarms. Once the craft is airborne and a few meter out they snap to 99 and stay there out to about 50 meters.

I feel like there should not be that big a drop at a few meters out. Have to flashed your RX with the latest FW again to see if maybe something went sideways with that?
SoCal Kaity :D
OMG, no one told me it would be this much fun!  Addicted :)
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#7
(09-Jan-2018, 01:04 AM)kaitylynn Wrote: Looking at your antenna positions, they look to be clear of anything that would rob signal.  Do you have another set of antenna you can mount to it?  Starting to wonder if there is not an issue with one (or both) of them.  When my quad is close to me, a meter or less, I oft see low numbers and even have critical alarms.  Once the craft is airborne and a few meter out they snap to 99 and stay there out to about 50 meters.

I feel like there should not be that big a drop at a few meters out.  Have to flashed your RX with the latest FW again to see if maybe something went sideways with that?

I have never seen numbers higher that 92. I do experience loss of telemetry on the bench, but it recovers at 1m+, which is to be expected. 

I've inspected my antennae and connectors and they seem to be in good condition. They've never taken a hit. I will order some spares to help in debugging this problem. 

The firmware is still the original I received the RX with. 

Would this be a good approach? 

1. Update to latest firmware
2. If fail, replace antennae
3. If fail, replace RX
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#8
(09-Jan-2018, 07:20 AM)xcalibur Wrote: Would this be a good approach? 

1. Update to latest firmware
2. If fail, replace antennae
3. If fail, replace RX

sounds like a good plan!
Keep us posted!
Don't be a LOS'er, be an FPV'er :)  My Gear - Facebook - Instagram - Twitter
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  • xcalibur
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#9
(09-Jan-2018, 01:04 AM)kaitylynn Wrote: Have to flashed your RX with the latest FW again to see if maybe something went sideways with that?

I've flashed the latest NONEU firmware and it definitely made a difference. On the bench I now see 103 and my range test has doubled to about 12-13 meters (with vtx on / off) before the taranis start squaking "RSSI low" (45).

Although this is still nowhere near the 1000-1500m range it is a big improvement. Do you think I should still swop the antennae anyway?

PS: Love that my Taranis has an s.port. Made this process so easy!
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#10
It is really important that the firmware in the radio and the receiver match. Unless you need to use the EU version firmware because of local laws, you should stick to the non-EU version.

One factor that can affect the performance of your receiver is where you have mounted it in the craft. If it's right on top of a switching regulator for example, the interference caused by the regulator can have a negative effect on the receiver.
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#11
(10-Jan-2018, 10:23 AM)unseen Wrote: If it's right on top of a switching regulator for example, the interference caused by the regulator can have a negative effect on the receiver.

Now you've got me thinking. My RX is on top of my stack. 

FRAME 
||
RX
||
X-Racer F3
||
HUBOSD8-SE PDB
||
FRAME

When USB powered the only regulator in close proximity is that of the FC. Not sure if that's switching or linear. 
When LiPo powered there are quite a few at play. The FC 5V regulator, PDB 5V BEC, PDB 10V BEC. I know the 10V BEC is linear, but the 5V BEC might not be. 

I will experiment with positioning a bit to see if it makes any difference. Is position the only solution, or can the RX be shielded in some way?
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#12
If you're running the X-Racer F303, you should be fine with the receiver on top. The small regulators that take the 5V power to the flight controller and create the 3.3V that most of the flight controller components use are linear regulators that won't put out significant interference.

I've seen some FPV cameras that upset a receiver if it's too close to them, but your position on top of the flight controller should be OK.

There's certainly something wrong with either the radio or the receiver as you should easily get 1000m range.
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#13
As much as I love debugging problems, I am starting to think that it might be easier to just replace the RX. If it doesn't fix the problem then it at least eliminates the RX + Antennae from being the source...which then opens a whole new box of questions. Smile
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#14
BUT then you have an extra receiver laying around so you HAVE to build a new craft to install it in.
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#15
(10-Jan-2018, 01:10 PM)Lowlife Wrote: BUT then you have an extra receiver laying around so you HAVE to build a new craft to install it in.

Agree! Was thinking along the same lines. I have A LOT of spares lying around from various "accidents". Have 2 sets of ESCs lying around I still need to figure out how to test for the faulty ones.
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