Telemetry lost and recovered on Taranis and X8R

[tintin]

Hello all
This was my first time using my new Taranis with an X8R with long range aerials.

I had the telemetry lost and recovered being called out by the radio during setup in the house.

I googled it and found it was probably due to it being swamped at close range, so decided to fly it.

As I took off the plane,I had the same problem again as I came back round to land it kept going in and out of signal for telemetry. As I has to do a large circuit to land I decided to just keep flying it as it wasn't locking out or anything. I flew for another 5 mins with it constantly going in and out of signal. I've not flown it since.

I've been flying a Frysky module in my old JR 9x for a couple of years now without a glitch, but this is knocking my confidence in the Taranis.

Any advice ?

[Kilrah]

When you say "long range aerials", do you mean you replaced antennas? If yes I'd look there first.

If not you might have a defective receiver on which the telemetry feed is not having the power it should. Do you have another one to try?

[Daedalus66]

I assumed he just meant the PCB antennas, which are claimed to give a bit more range.

Key question is was a reduced power range test done before flying?

[tintin]

Yes,
Sorry they are the PCB antennas. They came as standard with the Taranis combo. I just looked at the XR8 description and they were called long range. I haven't changed them.
I did a power/range check and it came up ok.
I tried it again a minute ago but I'm surrounded by cars and garage doors etc now.

What I did notice is that even on reduced power (a minute ago)the signal is good but drops to nothing at a certain angle from the plane.

I should say that when I did a range check I did not walk around the plane is a full circle like I a did a few mins ago. It would appear to drop out when the one PCB is pointing at me(but shouldn't the other be at max power)

I moved the antenna so that they are exactly 90 degrees ( they were pretty close before) apart. It did not change the dropping out of telemetry .

I have got another new X8R to try. I've also got a new V8 mk11 which I could put in there.

I managed to fly for 5 mins with it dropping in and out telemetry all the time ( reckless maybe) but I assumed it would have locked up straight away if the telemetry and other signal were directly linked.

Regards
Tintin

[tintin]

Ok
I did some more testing today.
I connected an old fashioned voltage indicator to the receiver to make sure that the battery pack kept a solid supply of current. I moved the servos and made sure the current stayed good. It did.

I then put the model in the garden and walked around it with the transmitter on full power.
Even when at about 5 or 6 meters from the plane I could momentarily get the RSSI to drop out and get the "telemetry lost and then recovered" .

As an exercise even when in the "Telemetry lost" phase, I could still get full control of the servos.

The RSSI signal and transmission to the servos are clearly not running at the same power .

Is the receiver faulty?

Tintin

[rapega]

Hi,

normally control of the servos has more range than telemetry, that is no surprise.

There fore the loss of the telemetry backchannel is an indicator for transmission problems,
not necessarily a control problem.

Did you check the simple things? That's what I always miss…

How did you place the antennas?
The transmitter antenna must not point to the receiver and vice versa.
That's why the receiver has two antennas.


Regards, Ralf

[outdoors4evr]

Could you share more about the position of the PCB antennas? (maybe a picture)

Are the antennas internal or external to the plane?
You mentioned they were repositioned to 90 degrees from each other. Are they both flat against the plane or is one turned up on its side?

What about the antenna on your radio? It should not be "pointing at" the plane. Orient the radio antenna sideways to the plane.

[tintin]

I'll try to post a picture at some point.

They are on the inside of the plane and near to some wiring and a closed loop rudder run. It's the only place I could mount the RX.

I didn't know, and didn't notice any specific guidance apart from placing them at 90 degrees

Tintin

[Flaps 30]

They are on the inside of the plane and near to some wiring and a closed loop rudder run. It's the only place I could mount the RX.

How near are the aerials to the wiring? ...

You need to keep the aerials as far as possible away from other wires. Anything right next to the aerial will have an effect on the performance of it, along with creating a shadow area that it cannot see through. How near is not that easy to decide. I like to keep the aerial(s) at least 30mm from other conductive materials like wires or servos.

You don't say if the receiver aerials are vertical or horizontal. Assuming that that they are horizontal in the aircraft, you will need to match that by making the aerial on the transmitter horizontal. If you set the transmitter aerial vertically, you will have a cross polarised situation in most flight attitudes and that will lead to a dramatic reduction in signal strength that could lead to a loss of control.

[JakeBullit]

The rx antennas are away from your lipo?

[tintin]

Hello
The aerials are away from the lipo.

I did take a photo but couldn't upload it.

The aerials are horizontal.


Within the realms of what's possible the aerials are as far away from the wires as possible. By default with a 2 1/2 to 3 inch aerial it's always going to be close to receiver wires.

I'm going to order some rat tail aerials and give those a go. They can be put through the skin of the plane if necessary.

Is there any problem with getting the longer ones?
Tintin

[tintin]

Hello
The aerials are away from the lipo.

I did take a photo but couldn't upload it.

The aerials are horizontal.


Within the realms of what's possible the aerials are as far away from the wires as possible. By default with a 2 1/2 to 3 inch aerial it's always going to be close to receiver wires.

I'm going to order some rat tail aerials and give those a go. They can be put through the skin of the plane if necessary.

Is there any problem with getting the longer ones?
Tintin

[Flaps 30]

The aerials are horizontal.

If the receiver aerials and the transmitter aerial is horizontal, then you are getting the best transmission path.

I'm going to order some rat tail aerials and give those a go. They can be put through the skin of the plane if necessary. Is there any problem with getting the longer ones?

Long range vs the rat tails/whiskers. I haven't tested the long range aerials, but I have tested out the rat tails and the performance of the rat tails leave a lot to be desired. I would suspect that the long range ones offer a far better performance by comparison.

The skin of the aircraft, unless it is made of some metal or carbon fibre will have little or no effect on the range you can get. Longer aerials (coax not the whisker that must not be altered) can be used with just a small reduction in signal level.

Have you tried doing a range check with the receiver out of the aircraft?

[tintin]

Ok
Ive reworked the setup.

It's on a sebart wind 110, and the receiver is on a small shelf behind the rear of the canopy opening.This is the standard location on these.

I made a right angled balsa support ( an L shape) and suspended one antenna vertically down into the bottom of the fuselage as far as the antenna wire would allow.( pointing straight down)


I made another shelf above the receiver and have mounted the other antenna as high as the wire allows, pointing directly backwards along the fus, exactly 90 degrees from the other.

I will try it again in the garden tomorrow.

To summarise, both antenna are now 90 degrees apart (in alignment) as far away from the receiver as the antenna wires allow.

I will let you know how I get on

Tintin

[tintin]

Well,
It still does it in the air, irrespective if the range check.

It appears to be that it's not the range bit the fact that there are blind spot which get larger the further away the plane gets.

I phoned the firm I bought it from and they suggested I update it to the latest firmware and try it again.

Tintin

[tintin]

Hello all
Just to let you know it must have been a fault with the transmitter.

I returned the tx and rx to the uk importer, as suggested on here.

They returned the same tx and rx and they said that they "updated the module"

I'm not sure what they did, but it now works as advertised, with no alarms in flight.

If nothing else it's taught me to use an optimised aerial set up, both in the plane and on the Tx.

Regards
Tintin

[sacalu83]

Hi, I usualy don't jump and open new topics so I'll just post here.I'll try to be short but also providing as much info as I have so bear with me please. I'm heaving problems with my Taranis X9D Plus EU mostly during range check but it also happend once during flight. I have two rx's on my biger planes for safety reasons, X8R's-EU, each one heaving half of the servos, it's own switch and accu (Life 1100mA). The telemetry is set active on rx1 and disabled on rx 2. I've flown with dual rx for years, and now for about one year with the Taranis. So..in the first seconds of range check, no mather if I'm at 3m or 25m, I see the RSSI dropping at zero and get the telemetry lost alert. The Tx settings are D16, channels 1-16, same rx number for both rx. Antenas at 90 degree both horizontal.
- This happens mostly to one rx (in one plane to rx1 the one with telemetry, in the second plane to rx2) but there were times when both rx stop working
- Although the red led on the rx is flashing when RSSI drops to zero, if I get close to it the link is restored and green led it's back on. So it is not the rx lock out type caused by ignition or other factors from witch the rx recovers only after restart, as discussed on some threads.
- The link it's restored by: getting closer to the plane or restart the Tx or restart the Rx.
- I've re binded the rx's but nothing. Changing the telemnetry from one rx to another doesn't solve it.
- After reestablishing the link, and exit range mode, if I go again in range mode, the link to one rx drops again somethimes, but it doesn't drop again if I remain in the range mode, after restoring the link(by getting closer).
- This link drop to rx1 in one model and rx2 in second model, happened at tests in one of about 3-5 range test entering, it doesn't always happend.
- It's like one of the rx looses signal when the Tx is in a certain position from the rx. In the house I had to keep the tip or tail of the tx antena towards the plane to loose link, outside, it doesn't matter because at a few metters it drops, about a third of the times..sometimes on one rx, others on both.
- One of the plane is 50cc gas, the other is electric, but I find that irelevant, just feelt the need to point it out, because the test where made mostly in the house, with the engines off. And there was not a lack of courent because I didn't even moved the controls in some tests when the link dropped, and accu are fine.
- I thought it's something about range test program, but one time the plane was at a few meters in flight and I heard telemetry lost. I didn't see anything wrong at the plane because the second rx was working, as it always does during house tests (in range mode), and probably the link was restored rapidly to the first rx also(the one with telemetry).
- Tried to power on only one rx, the one that drops the link in most cases, the link was lost. So it's not an interference between the two rx's.
- Also tried to restore the link to one rx by turning off the other rx, it did not.
I can't tell what it is, any advice is wellcome, since I'm the ony one around with RC and no one to ask.
Video link: https://www.youtube.com/watch?v=ybKOmH6PA7U