Frsky problem.

[Bodmer]

Hi,

I have run a test on a Jeti Duplex system which is another 2 way system that provides telemetry. This is from aTU transmitter module installed in an old Fleet Systems transmitter and the Jeti Duplex 4 channel receiver. The PPM plot is:

Jet Duplex system TU module and 4 ch Rx

Jeti Duplex ppm.jpg (101.34 KiB) Viewed 15405 times

Again this looks clean but I may be lucky with this setup, perhaps the frame rates are matched accidentally? Perhaps Jeti have locked the Tx module to the handset frame rate?

As you can see I am getting much better at moving the handset stick in a Sine wave motion....

I don't have any other "hack" modules to try.........

Any non-OEM modules are always going to be a compromise so if you really need the ultimate in smoothness stick to the old FM stuff or buy from a single manufacturer and pay the price. Maybe FrSky will produce their own "two way" handset eventually and then the problem will be solved for sure! In the meantime perhaps some software updates could mitigate the jitter effects.

ATB,
Bodmer

[mr.sneezy]

It does the job for me well enough with the 22ms frame period and I would not have noticed the jitter had I not tested the unit with a 15ms and 18ms frame periods.ATB,
Bodmer

Hi Bodmer, hey which radios are the ones with the 15mS and 18mS frames ?
I have a friend asking me for more information about that, particularly the model and brand

[mr.sneezy]

Any non-OEM modules are always going to be a compromise so if you really need the ultimate in smoothness stick to the old FM stuff or buy from a single manufacturer and pay the price.

One that would be interesting to see is the Spektrum DM8 Module made for Futaba radios, although then the frame rate will be 22mS from a Futaba TX. Putting 18mS frames into it from your test jig might be interesting, to see if it copes better.

[takilara]

I was wondering if you could publish your test setup. I think you mentioned using an Arduino. I have an arduino i could use to make measurements as well. (it's currently being used as a simulator for my telemetry dashboard)

[Allan Warner]

Below is a copy of my post on the GiantCod forum, reproduced here to ensure a full dissemination of information.
''Well, up bright (not really its North Wales and raining) and early this Saturday. I thought, as I have other Futaba modular transmitters, lets do some final tests! So, I did the following:
1/ Futaba FF8(FP-T8UP) transmitter, FrSky Telemetry Tx modul, Telemetry 8 channel rx and a non telemetry HV 8 channel rx, Futaba S3001 servo(new), 5 cell 1800mAh NiMh rx power pack.
Results were the same, coggy servo response, using telemetry or non telemetry. Confirming my original test results.

2/Futaba FF9 (T9CP Super) transmitter, Spektrum DM8 Tx modul, Spektrum AR6110e 6 channel rx, same servo and power pack as above.
Result was a smooth and proportional servo o/p that followed the stick movements at all times.

3/ I then removed the FrSky modul from the Futaba FF8(FP-T8UP) transmitter and installed it in the Futaba FF9 (T9CP Super) transmitter. I then conducted the test using telemetry and non telemetry mode with the same result of coggy servo o/p as observed in ''1/''

This, IMO, eliminates any possibility that there may have been any sort of fault condition with my original Tx. I have another Futaba FF9 (T9CP) that I could use, but I don't think I need to go that far.

Yesterday I emailed FrSky direct to advise of my problems and provide them with the links to this thread and the link to the thread on RC Model Reviews forum. The reply thanked me for my feed back and informed me:- ''We are about to release a new ROM version quite soon to solve this problem. I am wondering whether you are happy to accept our sample for your test then?''
I think I will accept their kind offer of a sample of the new ROM version for test. What to do with the units I now have??''

[mr.sneezy]

Use them in something that has slow servos or give them away to somebody who can't afford to buy new gear... That's what I do.

[takilara]

Isn't the units firmware upgradeable? specifically if they are just changing the ROM?

if you suddenly have one Rx too many, i guess the solution is to get an additional plane or heli:)

Or for a complete blast, mount a .50 size nitro engine on a pair of skis and see how fast it goes

[RCModelReviews]

I have heard from FrSky that they are releasing new firmware that will deal with the servo-stepping problem some folks have observed with their 2-way systems. It'll be an in-field upgrade with users being able to reflash their own 2-way transmitter and receiver modules with files downloaded from the FrSky website.

[Allan Warner]

Had an email reply from FrSky re ROM revisions (you beat me to it due to the time diference):-
''Hello Allan,
I am coming to update with you that we will release new ROM versions for two way telemetry system's TX module and RX quite soon, which will solve jerkiness problem. Besides, we will make manuals to guide users how to upgrade step by step, by applying some photos and notes. I will surely keep you updated as soon as they are ready, thanks for your attention.

Best regards!
Eva''

The question now is will the revised Tx module, when in normal non two way mode, opperate the standard Rx without the 'coggy' servo response?? We'll have to wait and see!!!

[jet760]

Well at least they listen to every one. I was one of the first to report this to them. I told them that people just wouldnt accept it as it just the way it is when other brands don't do it