How do you find the limits of your TX/RX range and recover should you exceed it?

[jweaver]

My assumption was that my video range would be the Achilles heal of my setup.. But I discovered this week that the limit of my quad (Using a DX8 and AR6210) was a paltry 400m.

This wasn't actually a problem as the quad has a FS and that kicked in and bought itself home.. But how do you go about finding the limits on a plane which does not have a FS?

Obviously you can do some kind of ground test, but thats not really going to work.. The only way seems to fly, but when you go too far, its too late.

I am currently building FPV into my WOT4 (using an Orange RX for the first time) and that will have an AP/RTH, so its not a big deal...

But for my Radian glider, I have simply got a backpack (With Camera, OSD and TX) and am only using an AR500, so how do I find my limits?

My assumption was that teh first thing I should do was setup the RX FS to zero throttle.. And then circle above me gaining hight until I loose signal.. Then the engine should cut and it should stall and drop back down into range.. But this could go wrong, if it doesn't stall and just glides out.

I also wondered if you could attenuate the TX antenna in some way.. Then when you lose control, you could just remove teh attenuation (i.e bag over aerial, point the antenna down, etc)..

Does anyone have any advice on how you go about this? Or is it simply that if you don't have FS/RTH you should not exceed LOS limits?

Any support/advice would be greatly appreciated


Jon

[Ratty]

Sort answer, ground tests.  ;D They do work well.

Set the fail safe to zero throttle, either level so it just glides down, or with a light turn so it circles down and maybe back into range.

We have been out to over 1.5km on Spektrum Dx8 and AR8000 on a quad. You should get at least 1km range.

Also make sure you are using DSMX not DSM2. Don't understand why you would want to cheap out on a Rx. Why risk £100s of stuff for a few more £.

[HerkyBird]

Why the comment re DSM2, is it shorter range? The reason I ask is that I use a module in my old 9XII and wondered if there may be range issues?

[jweaver]

Also make sure you are using DSMX not DSM2. Don't understand why you would want to cheap out on a Rx. Why risk £100s of stuff for a few more £.

What do you mean by "cheap" RX? Are you referring to my choice of an Orange on my WOT4?

Believe me, i didnt intend too.. But after a length debate with other members of the forum i wae convinced that it was a good product, comparible to the genuine spektrum RX.

I think i just need to realign my expectations of range.. Instead of assuming i could go miles, i am just gong to stick "local" and enjoy it for what it is...

[FPVSteve]

Someone already told you what I'm going to because it's the best solution:

Get a Frsky telemetry module for £30, a Frsky D8RII receiver for £25 and a Turnigy 9x/9xr for £30-50 ... you'll have an instant 1-3km control range, with telemetry that warns you via beeps that get progressively  quicker as you go out of range so you get a chance to turn back.

If you want to go further, grab a patch antenna for the Frsky module which should in theory double your range again straight out front.

Further still, the 9x/9xr will accept a UHF module.

Honestly, it's worth the investment.

[FPVSteve]

Additionally, maybe your range issues could be ironed out with a better setup? Would be interested to see pics of how you have things laid out on the quad .. I'd expect more than 400m control range from a well setup system (even if it is Spektrum).

[keukpa]

On a Turnigy 9x with DJT module and dipole antennas I've done 2.8km.

[Ratty]

They are both right, if you want long range you will have to change control systems. However, you should be getting further than 400m with any radio. Id be interested to see your layout too.

Yes I did mean about the orange Rx, although they have been tested and I know people use them and they work fine, I still don't see the point in cheaping out on one of the most important components.

DSMX is the newer version and has better range and link quality than DSM2. I have never seen both systems tested side by side tho, its just what I, and other have experienced.  ;D

[jweaver]

They are both right, if you want long range you will have to change control systems. However, you should be getting further than 400m with any radio. Id be interested to see your layout too.

Yes I did mean about the orange Rx, although they have been tested and I know people use them and they work fine, I still don't see the point in cheaping out on one of the most important components.

DSMX is the newer version and has better range and link quality than DSM2. I have never seen both systems tested side by side tho, its just what I, and other have experienced.  ;D

I will upload some photos tomorrow. But i have just finished my FPV "backpack" which means i am ready to fly my Radian (with an AR500) so will be interested to see what range i fan get with that.

One thing i do wonder if its significant. My AR6210 antennas are not straight. The one on the RX is horizontal but it tends to bend up.. And the satellite is mounted with the antennas vertical but those wires are bent too and tend to fold back.

I wonder how important it is to get them "straight"? I am considering adding some "tubes" to make them rigid.

I am also going to do a range test this week (reduced power) and am going to go right to the limit to see how far i can walk away before i loose signal...

[jweaver]

Was thinking today about the suggestion of putting a bit of left/right stick in on failsafe to get the plane to circle.. But my RX only supports throttle in FS.

So I wondered, is it bad form to setup the rudder (this is effectively the aileron on the Radian) so that its always pointing a bit left/right.. And then using sub-trim to put it straight.. That way, when if FS kicks in, the controls will go back to Zero which will then give me a bit of rudder and get it circling.. Is it bad form to do this?

Jon

[rob.thomson]

My honest feeling.  Get a better radio :)

By UK law, your throttle should always cut if you loose signal.  This is for safety.  Last thing you want is a motor driving your model full speed into somebody!

[jweaver]

My honest feeling.  Get a better radio :)

By UK law, your throttle should always cut if you loose signal.  This is for safety.  Last thing you want is a motor driving your model full speed into somebody!

Motor Cutting isn't open to debate.. Thats a given and thats how I have it set up. But I want to put in a bit of left/right stick so that it circles, so rather than buy a new RX, I was just wondering if I could achieve the same with "Sub Trim"

There is no doubt that changing the radio could solve some of my problems.. But to be honest, this whole range thing makes me nervous and I am more than happy to stick 'local' and fly around in a 400m radius.. But I just wondered if anyone had any tips on how to find your limits, without loosing the plane for good..

And it seems that zero throttle and a bit of rudder would work as it would allow it to circle slowly down giving me time to move towards it a few meters to gain control again!

[FPVSteve]

you can't put in a bit of "left / right stick". .. if you do, it'll be like giving it continuous left/right stick, so it'll not circle, it'll keep banking until it's inverted... sort of like a slow roll.

[Loopdreams]

You definitely could trim a glider like a radian to fly in a circle.  It effectively has dihedral so it'll want to stay the right way up.

[jweaver]

you can't put in a bit of "left / right stick". .. if you do, it'll be like giving it continuous left/right stick, so it'll not circle, it'll keep banking until it's inverted... sort of like a slow roll.

Its the rudder.. Its a 3 channel radian and thats the only left/right control it has, so you can stick a bit of left and it keeps turning. If you go to far, it will start to role, but a few degrees seems to hold/circle.

I am going to do some tests tonight, just to be sure by dialling in a bit of trim to see how much I can get away with.. But in principal, is it bad form to set the rudder off center, and then using sub-trim to bring it back?

Jon