Frsky X8R Antenna

[George_uk]

Some Taranis/x8r questions...

I changed the PCB antenna to the 400mm extensions you can buy. The PCB ones just clip off and the new ones clip on so that was easy.

I've routed the cables out into the wings of my AXN.

One is lying flat, so 90 degrees. The other I cut a small hole so the antenna can poke through down towards the ground.

My questions are: Is this a good setup? Should I poke the other antenna out the top of the wing so they are 180 degrees apart? Do the long 400mm extensions affect the range?

I flew out to around 1 / 1.5km and had an eye on my RSSI in my Cyclops OSD and noticed at that distance as soon as I turn back it drops for a couple of seconds down to about 10 or 15 before coming back up. Is this normal?

Also I have the antenna bent 90 degrees on my Taranis as they advise and notice for best RSSI I have to point the radio at the plane. Flying behind myself I have the lady telling me RSSI CRITICAL.

[CurryKitten]

Keep the antennas 90 degrees apart, this is best for the antenna diversity.

The 40cm extensions (with the sleeve dipole) are effectively the same things as the PCB antennas but should allow you to run the antennas further away from other components and thus have a better chance of keeping your signal.  I got about 1.6km with normal antennas, and 3.5km with the extensions.

As you turn around you have more chance of the lipo in the nose blocking you - it certainly not unusual for video signal to get block this way, control signals can get blocked as well.

Define point at the plane.  What you don't want is the tip of your antenna pointing at the plane, this is the null of the signal and will affect the range negatively.  You want your antenna stood up vertically like a tower - obviously you'll always get a better signal if you have clear los to your plane though

[George_uk]

Hi CurryKitten

Am I correct in thinking its just the very end of the antenna that needs to be kept straight?

If I have the one in the picture above pointing downwards and the other is left running straight along the other wing that would mean they are pointing at 90 degrees and very far apart from any of my gear.

Is it normal for my RSSI indictor in my OSD to be dancing around a fair bit? It's doesn't drop in a linear fashion like 100,99,98 as I get further away but instead will jump randomly from 65 - 100 and then in the turn it may go down to 15.

I fly with the antenna on the Taranis as in the picture below. If i point it directly at the plane as I have it at the moment I get better signal... but the antenna isn't pointing directly at the plane as it goes off to one side. Might try pointing it stood up like you suggested.

My video is solid the whole time which is great :D

[CurryKitten]

Hi CurryKitten

Am I correct in thinking its just the very end of the antenna that needs to be kept straight?

Yep, just the exposed ends

If I have the one in the picture above pointing downwards and the other is left running straight along the other wing that would mean they are pointing at 90 degrees and very far apart from any of my gear.

Sounds good, in a V is another popular config, but having the 90 degrees means you have the best set up for antenna diversity

Is it normal for my RSSI indictor in my OSD to be dancing around a fair bit? It's doesn't drop in a linear fashion like 100,99,98 as I get further away but instead will jump randomly from 65 - 100 and then in the turn it may go down to 15.

As you are using an X8R, are you using some sort of RSSI buffer in order to read an analogue voltage from the PWM, or does your OSD read PWM based RSSI ok.  If you are trying to read PWM as analogue voltage then it will usually jump between 0 and 100 without much inbetween.  I've got my X8R hooked up to an OSD for RSSI and it doesn't do an awful lot... but I don't really trust the OSD much either, so who knows.  On other brands I've looked at you should expect it to fall off reasonably linear, but you do get odd times when it might suddenly drop dramatically and recover.

I fly with the antenna on the Taranis as in the picture below. If i point it directly at the plane as I have it at the moment I get better signal... but the antenna isn't pointing directly at the plane as it goes off to one side. Might try pointing it stood up like you suggested.

If you fly like that, then pointing at it might be necessary - should you be at a distance on the left or yourself for instance, you are pointing the null at it.  I try and work out exactly how I will hold my radio, and then angle the antenna so it should be vertical in that position.  Covers a wider range that way.

My video is solid the whole time which is great :D

Good - you'll quite likely be able to exceed the range of your control signal with your video link though

[George_uk]

As you are using an X8R, are you using some sort of RSSI buffer in order to read an analogue voltage from the PWM, or does your OSD read PWM based RSSI ok.  If you are trying to read PWM as analogue voltage then it will usually jump between 0 and 100 without much inbetween.  I've got my X8R hooked up to an OSD for RSSI and it doesn't do an awful lot... but I don't really trust the OSD much either, so who knows.  On other brands I've looked at you should expect it to fall off reasonably linear, but you do get odd times when it might suddenly drop dramatically and recover.

Im using Cyclops Breeze Pro OSD. I've wired it going from the x8r to the Breeze RSSI port and then configured MAX and MIN in the OSD menu. Seems to work reasonably accurately but like you say I wouldn't 100% trust it. I supposed the good thing about the Taranis is you get the audio warnings to make you freak out.

[CurryKitten]

It shouldn't be very accurate at all, the x8r was released with a manual saying it would put out a 0-3.3v analogue RSSI signal, but it's actually got a PWM output.  You'd be better off just getting your Tarnis to announce your signal strength really.