Constant noise from speaker

[sandrodadon]

Hi everybody !

When i start my Taranis i hear "Welcome to Taranis" but after that there is a constant (rather silent) background noise all the time - It comes from the Speaker and i can control it a bit with "Volume" but i cant turn the Volume 100% down.

Do you have those issues too?

Edit: Now i hooked up headphones (which sounds much much better ) but the "background noise" is still present so i guess its a OpenTX Based Bug?

[ShowMaster]

Yes the noise is there.
You should load he new audio pack in c9x if you haven't. It's audio is much better. It won't stop the noise but it's gain structure tames helps.
In fact the latest opentx has much improved brightness, and contrast features also. The stock Frsky open tx hasn't.

[sandrodadon]

There seems to be a solution:

"I had the same problem. I opened up the back then connected the battery and moved the wiring looms one by one slightly. The buzzing disappeared after a bit of fiddling. I am not sure which wire was the culprit or why but it was an easy fix. Something must be giving off some RF that the internals can pick up when the wiring is in a particular position. "
(http://www.rcgroups.com/forums/showpost ... count=8322)

Anybody tried that? If yes: Could you tell me which wires i have to reposition?

[dvogonen]

I also have a high constant background noise. It is clearly due to some kind of interference within the transmitter. Surprising and not at all acceptable that FrSky has been so sloppy with the shielding of the audio circuit.

[Rob Thomson]

I cut our allot of the him on mine by wrapping each wire group inside the to with a ferrite clamp.

This has remove allot of him, but not all.

My final fix will likely be a simple low pass filter.

Sent from my GT-I9300 using Tapatalk 2

[ShowMaster]

Good info Rob.
I believe the skyboard has a good low pass filter in it according to Brent when I asked him. The skyboard really does have good audio.
Your low pass idea may be the best fix.

[rperkins]

I cut our allot of the him on mine by wrapping each wire group inside the to with a ferrite clamp.

that sounds like a good idea.

what kind of noise is it
Is it power supply noise like from a dc switching supply ? the digital data getting amplified ? or just plain audio gain noise ?

[ShowMaster]

I believe it could be actual 2.4g data being picked up by wiring resonate with 2.4g. Of course data has a lot of harmonics it it also. Just hold an AM radio next to your favorite computer case.
One test to try is to set the menu to use the empty module bay instead of the internal rf deck to kill the rf if that's what will happen. That or see what happens in the range check mode that should cut the rf way down.
I'll try it all myself tomorrow.

[Kilrah]

It's the RF hopping that you hear.

[rperkins]

thats cool. Does the radio use one of the cypress chips ?
CYRF69103 ?

[Kilrah]

No, FrSky gear uses the CC2500.

[rperkins]

I was looking at the datasheet. It mentions 26mhz crystal. is that what radio has ? is there a schematic out yet for this new radio?
I guess the speed of the hopping is dependent on the calibration method. 810, 90, or 240 us. (page 55 datasheet ) So would that translate to audio noise at 1.2khz, 11khz, or 4.1khz khz ?

[jhsa]

is there a schematic out yet for this new radio?

One can keep dreaming

[Kilrah]

A packet is transmitted every 9ms, so that translates to about 110Hz. The noise is created by the RF being turned on and off for each packet, just like the typical 217Hz buzz created by GSM mobile phones when they're close to some audio equipment.

[sandrodadon]

Wow this thread exploded in the last ours

What is going to be the best solution?
-shielded wires?
-low pass filter? capacitors?

I kinda hate that i have to work inside my Taranis now - because thats why i sold my 9X and bought a Taranis

Hope we will find a good solution where we maybe just have to put a filter between the wires

[rperkins]

A packet is transmitted every 9ms, so that translates to about 110Hz. The noise is created by the RF being turned on and off for each packet, just like the typical 217Hz buzz created by GSM mobile phones when they're close to some audio equipment.

I didnt know about the GSM/TDMA buzz . Here we mostly use CDMA.

anyway , whether the tx transmits on every hop or just the ones it has some data, this may be helpful. Just glancing I didnt see any mention of ferrites, but I still like the idea. What looked promising here was the use of a few caps to overcome the PCB design shortcomings.

http://www.edn.com/design/analog/432836 ... ell-phones

I wonder what the freq of the noise is? further wonder if a smartphone could decode the frequency if you dont have a scope. There are lots of 'guitar tuner' apps out there for free.

[sandrodadon]

Statement FrSky:

We have aware the background noise things and improving on the 2nd batch. It is caused by the power module,
To solve this you need to change some SMD components. i.e. LDO. It is not suggest to change them by user-self.

[jhsa]

Power module??

[ShowMaster]

? I agree, RF or DC?
I guess those complaining they weren't first buyers will now relax and be glad they were slow on clicking the buy icon!
I'm counting on my warranty and just going to fly mine until it's time for the fixes.

[fireball]

Is there any more information available on the needed modification so that we early-adopters may be able to fix it by ourselves?

[ShowMaster]

I think it's too early to do a DIY fix. My plan is to wait for the next 2 batches to be delivered. If at some point it's obvious that Frsky has engineered fixes for the noise and stick centering I'll look into getting all upgrades done via the warranty. Only if that isn't happening will I DIY. By the time I'm sure the fixes will be documented and proved to work.

None of the current flaws are keeping me from flying so personally this time I'm not rushing to modify my radio that's under a 1 yr warranty with Frsky and a local dealer. The dealer has acknowledged that my issues are on record and so we'll see how that goes.
I'm sure each new batch of Taranis radios will have changes and mods to improve the product based on the feedback from the owners and beta testers that read these forums. That and the dealers input.
This being a first version owner has it's good and bad points. Fortunately more good than bad!