frysky protocol and jitter

Hi guys,

I have modded my devo 12 s with a cc2500 pa na module.
When my rx and tx are connected then a jitter appears.
I can see on the screen of the transmitter channel monitor that the transmitter produces the jitter.
The transmitter produces some output on the channels
The jitter is on all channels (servo's) .
Can someone tell me what can cause this transmitter jitter ? It's only on the frsky protocoll (both).
When i choose the devo protocoll everything is normal

thanks

albert

Hmmm interesting I can confirm that jitter too (U7E) up to 3ms, I expected it was something to do with voltage of my Tx not being stable, but no so sure anymore especially as you mention you only see it on Frsky.................

is it possible that i connected the wires wrong on the cc2500 module?

hydro wrote: is it possible that i connected the wires wrong on the cc2500 module?

If it was connected wrong it would not work at all ( plus it'd throw an error) so that's not really a possibility Imo.

No, this comes from the Devo pots and telemetry. The same receiver bound to a DFT on a Futaba does not have it that much.
Test:..... set the protocol to frsky-V8 and it will stop......at least on my transmitter.
If you use the receiver on a quad, set some deadband at the FC and you are good to go.

when i set the protocol to frsky-v8 then the jitter doesn't stop .Even the battery voltage jitters on my screen .it is not stable.
I checked every connection and wire . But i can't figure it out where the jitters come from

How technical are you? Do you have a scope or logic analyzer?

Do you just want an answer or are you looking for a solution? (i.e. are you willing & able to put time / effort into diagnosing this?)

There's a chance the best / only option to even try will be a replacement RF module... which specific cc2500 did you use (banggood SKU # or other link)?
It'll be easier to try a $6.99 module than spend hours HW debugging only to conclude you want to spend $6.99 on a replacement module anyway.

*If banggood please verify which EXACT SKU you got by checking your account and your purchase history (or the packaging if you still have it)

you are right. I will try another module .
I bought two different modules .
When using this module where i have to solder the antenna ?
www.banggood.com/2_4G-100mW-TI-CC2500PA-...-24PA-p-1071503.html

Spend the $3 extra...

m.banggood.com/CC2500-PA-LNA-Romote-Wire...F24L01-p-922595.html

that was the one with the jitter problems .
I soldered the "cheap"one and this one is more stable
The jitter is almost gone . But not as it should be .I am still wondering where the jitter comes from?
I think that i will order a 3 in one module

Did you make sure you got that specific module [the "blue" one, though note the blue color only comes from cling-wrap, it's actually just bare metal color under there]?
There are 3 different modules that look the same (literally, EXACTLY THE SAME), that's why I've put so much emphasis on the SKU. Make sure you got that specific module, that's the one we all use without issue (sku 922595). I have that module in both my D10 and U7E and neither have jitter on any channel at all. If you're SURE you've got the right module then I'd start diving into more HW debugging, things like RF interference from where you have it mounted in your devo or wiring issues or something [IDK what] else.

That a module can be off tune, I can understand, due to X-Tal or capacitance offset in the design.
But jitter I can't believe the module affects that.

The pots are converted into digital value by adc than transmitted over spi, so digital. (works or not works)

However I have voltage fluctuation in my tx readout particularly when using Frsky.
If voltage fluctuates it could be that it might affect the jitter. Will check necxt time if switches also jitter or only the ADC channels.

i have checked what i have ordered and it is the same module .
1 x CC2500 PA LNA Romote Wireless Module CC2500 SI4432 (922595)
with this module i have jitter on all channels. The voltage on the display goes up en down.
There are little misplaced dots on the display .Choosing the devo protocol they are gone
As i mentioned before the other module does have jitter but less than the 922595.
Only on channel 3
1 x 2.4G 100mW TI CC2500+PA Wireless Transceiver Module WLC-24PA (1071503)
the voltage fluction is more stable. But the coloured misplaced dots are still there.
I am certain that everything is soldered on the right way