olnico

Hello guys,

I've been flying the Weatronic system this week-end and here are my data.
I am posting this mostly to help people in achieving a reliable diagnostic of the RF link and build up data statistics.

Here is the data of flight 2 ( typical flight ):



Lowest RSSI on receivers: -85 dB
Average in flight: -75 dB

I had an event during the flight as shown on the diagram above at 05:00
Frames going from 100 down to 20. Error code: 168. No error LED on the Tx box. No link lost, no failsafe frame, not noticed in flight.



Error 168 is a data link break due to antenna masking effect ( Tx side ).
This happened during the flight where my spotter went briefly in the transmission line. Here is the real power of this system. One can see thing that would go totally unnoticed on a Spektrum or FASST system.

Guys, please post your results for comparing.

olnico

Here is how to proceed to get the data.
Insert the micro SD card in the TX module prior to the flight.

After the flight remove the card from the module and insert it in the SD adapter if required.
Download the data to your computer.

Open GigaControl 2.07.
Go to the the Nav View window.

Configure Nav View as follows:

Right panel upper window Rx data ( RSSI1, RSSI2, Frames1, Frames2 ):

Erase all the data on the right panel.
Hit the + button and select the following:
"receiver", then RSSI 1rx, then RSSI 2rx, then frame rx1, then frame rx2.



Right panel lower window Tx data ( RSSI1, RSSI2, Frames1, Frames2 ):

Hit the + button and select " diagram below".
Select again the + button and the following:
"transmitter" then RSSI 1tx, then RSSI 2tx, then frame tx1, then frame tx2.




Left panel alfa numeric values and error codes:

Right click on the title box and select "hide all columns"



Then right click again on the title bar and select "receiver" then Frame rx 1, then Frame rx 2, then status rx ( optionally Failsafe ).
Do the same thing with "transmitter" then frame tx 1, frame tx 2, then status tx



You should end up with the following display:



You can now load the nav file by hitting the "open" button and selecting the file target.
The data log will open automatically.
Center the graph to the flight zone ( you will recognize it since the RSSI start to drop when the plane goes away from you ) and zoom it to get rid of the post and pre flight crap.
Select the wrench button on the right panel and select "Y-axis scaling" then "scale possible values"



This option will enable you to evaluate the values compared to their maximum. It is very important to select this option otherwise the graph will not "talk" to you. The program is configured to show the "visible values" by default.

If you see a zone of the flight that you want to evaluate more precisely, then center it on the dotted line, dragging the horizontal button. Then left click on the dotted line. This will automatically pull the associated line on the left alfa numeric panel and highlight it. Note that these lines are only recorded every second on the tx side with the micro receivers. The big receivers can record at a much higher rate on the rx side ( rx micro sd card ).

In the example below I have zoomed on an event in flight 2 and clicked on the dotted line:




The line at 317s is automatically displayed in the left panel and highlighted. I then just have to read the values...

Note that the RSSI values can fluctuate between -110 dBm and -8 dBm, -8 dBm being the highest value ( best reception ).

There are 100 frames per second of which 45 source frames ( flight orders ) . Anything below 100 means that you have lost some of the frames( like the A,B,L,R data on the Spektrum flight log ).
However, the order frames are more than doubled ( 100 frames transmitted for 45 source frames ). So the RF link is very strong.

The error codes are shown on the left window for both the Tx and the Rx.
136/168 means loss of feedback link for the Rx/Tx with no loss of order transmission.

jeanfi

Hello Olivier,

Great ! I made 2 flights this week end in a litlle plane. Your help is good !

Thanks
Jean Philippe

Aquilon

Hello Olivier,

I have made 2 flights Saturday morning with my Boomerang XL / Wea 2.4 / Rx Micro 12.

I have noticed exactly same as you 3 or 4 times during each flight : "168" code on the TX, with no red led flashing and no failsafe.

Best regards.

Stéphane

Carsten Groen

Wondering,
why is there a loss of signal from the plane to the TX, and not the other way around ?
Does the "plane" transmit with a lower power than the "transmitter" side (so that the link FROM the plane TO THE transmnitter is more prone to errors ?)

olnico

I am not 100% sure about the answer Carsten but it seems pretty reasonable to say yes: the uplink has the priority versus the downlink yet the two way communication can be interrupted due to a downlink error.

olnico

Guys, could you post your flight data here ( same format as expained in the second post ) so that we can have more feedback from different planes/setup ?

I'd especially like to see what Rx/Tx RSSI 1/2 look like for your setup on a complete flight.

Thank you very much in advance.

David Gladwin

I'd say your flight is pretty typical judging by all the data I have accumulated this summer on a 12 Micro. I have never seen an error light until last week when after landing I looked down at the Tx and it WAS flashing. Data download showed code 168 , data downlink lost. The light went out when the link was restored.

I had seen this code on data printouts before but did not know the significance and discussed with Alwin who sent me the error code decodes. 168 just shows that the downlink was lost (unidirectional) and it happened to me ONLY when on the ground about 100 m away with lots of people in the pilot box. There was no loss of control. the downlink uses only the left antenna, viwed from the rear and this is the horizontal one in my BobCat and the downlink was lost briefly when the model was turning such that the aerial was behind fuel pumps and other equipment. No fasilsafe frames recorded.

I am not sure but I THINK that although during the loss of downlink the data shows a loss of frames, there is only an APPARENT loss of frames because of the reduced number reported by the degraded data link. Alwin/Gerhard may be able to comment.

Still have not recorded a single failsafe frame.

Regards,

David.

PS I have also noticed that the number of source frames is 45 in PPM but only 24 in PCM BUT you get a full 10 channels with PCM on a JR 10X which transmits only 9 channels in ppm.

Is anyone using the Weatronic Tx with a JR 12x ?

David Gladwin

Here's a bit more data. Looking at my readout my codes on the flight I referred to were receiver: 136 comprising of code 8 and code 128.

Rx code 8 is Rf link OK (bi or inidirectional)
Code 128 is Rx in unidirectional mode.

Add the two = 136.

Tx code is 160 consisting of codes 32 +128.
Code 32 is Tx is transmitting correct frames.
128 Tx is in Unidirectional mode.

Add the two=160

A Tx code of 168 comprises 8 + 32 + 128.
8 is rf link OK.
32 is Tx transmitting correct frames.
128 is Tx is in unidirectional mode.

Add the three= 168.

I have seen some brief 168 codes on earlier flights but always on the ground. In flight (judging by position of gear servo as the micro has no GPS) Tx stays on status 40 and rx on staus 8 showing all is solid.

For those not familiar with the codes, they double contunuosly (2,4,8,16 etc. ) so that a total code number can consist ONLY of specific numerical codes allowing a final code number to be broken down into individual numbers each of which refers to a specific code.

Regards, David.

PS Today the big DR 12-30 plus GPS plus 3 gyros goes into the PST reaction then into my FC Mig 29 for autostabs on all 3 axes.

ddennison

My Feedback: (15)

Is the 2.4 system working on 100 frames instead of 45 as in my 12-20 PCM gyro/gps receiver?

ddennison

My Feedback: (15)

Is the 2.4 system working on 100 frames instead of 45 as in my 12-20 PCM gyro/gps receiver?

David Gladwin

The transmitted data is 100 frames, source frames are 45 in ppm , 25 in SPCM.

Regards, David.

olnico

Guys I have updated post 2 with detailed information on how to configure the NavView window to effectively monitor the system's performance.

If you could please send screen shots of your data with this formatting, it would certainly help the community and give more feedback to everyone.

Once again here is what I got so far:



Micro 12 receiver on JR 10x. PPM mode. World (besides France).
Antennas at 90 degrees on the horizontal plan.
Left antenna on the pitch axis, right antenna on the roll axis ( as seen from the front )

And the data analysis for the flight:

Lowest RSSI 1 rx: -85,5 dBm
Lowest RSSI 2 rx: -84,5 dBm
Lowest frame rx1: 20
Lowest frame rx2: 21

Average RSSI rx values: -70 dBm
No failsafe
4 losses of feedback communication ( 136/168 events ) for a total of 7 seconds


Lowest RSSI 1 tx: -99,5 dBm
Lowest RSSI 2 tx: -92 dBm
Lowest frame tx1: 9
Lowest frame tx2: 9

Average RSSI tx values: -87 dBm

So the Tx side is clearly weaker than the rx side, which makes sense: the data coming back to the Tx is less important than the data uplinking to the Rx ( flight orders ).

I will next experiment on the range warning slider to adjust it so that the margin before warning is optimal ( probably 20% margin ).
I have already increased it to 50% with no warning going on.
I will increase it by 10 % every flight until I get a warning in normal operation, then reduce it by 20%...

olnico

Thank you David for the valuable information about the error decode.
From what I understand, a loss of data feedback is not that important since it does not include flight orders.

The source frames being 24, 25 or 45 out of 100 transmission frames means that there is a big redundancy in the system. I am pretty sure that the source frames are reproduced in every communication frame, so that out of 100, the orders will be doubled or quadrupled...

olnico

Hi Stephane and Jeanfi. Good to see you here.
Please upload your results here. It will take only 5 minutes of your time and help a lot of people:

Type of receiver:
Type of Tx:
PCM/PPM mode?
Region?
Antennas angle and on what plan ?
Left antenna on the xxx axis, right antenna on the xxx axis ( as seen from the front )?

And the data analysis for the flight:

Lowest RSSI 1 rx:
Lowest RSSI 2 rx:
Lowest frame rx1:
Lowest frame rx2:

Average RSSI rx values:
Failsafe ?
losses of feedback communication ( 136/168 events ) for a total of x seconds ?


Lowest RSSI 1 tx:
Lowest RSSI 2 tx:
Lowest frame tx1:
Lowest frame tx2:

Average RSSI tx values:

Thank you so much...

Aquilon

Hello Olivier,

Don't worry, I will upload my screen copies tonight...

Stéphane

olnico

So David, when looking at the micro 12 receiver with the plugs in front of me, the downlink antenna is the one on the right side. Is this correct ?
The uplink ( flight orders ) using both antennas of course...

olnico

David, do you know what LQI means in the receiver configuration window ?
Link Quality Indicator ?
I noticed that when doing a range check, the LQI values would drop from 100 to 80 or less at the end of the range.
However I don't know how to interpret this data.

olnico

Great

Carsten Groen

Thats good news Oliver, explains perfectly why there is a loss from the plane to the transmitter

ddennison

My Feedback: (15)

David and Oliver,

So the 2.4 system uses either ppm or pcm? Which are you finding is better? I would guess pcm?

I really like my weatronic and have to change the A10 to 2.4 soon...

Thanks
Dave

Aquilon

Hello again,

Hereafter my data for 2 Saturday’s flights :

Multiplex Profi MC4000
Country : France
Modulation : ppm-12
Micro 12 receiver + Emcotec DPSI 2001 RV
Antennas at 90 degrees on the horizontal plan.
Left antenna pointed to the backward fuselage
Right antenna pointed to the right side of the fuselage

Flight 1 : No failsafe / 4 losses of feedback communication ( 136/168 events )

Flight 2 : No failsafe / 1 losses of feedback communication ( 136/168 events )

Stéphane

olnico

Thank you very much Stephane.

Could you do it again with the Y-axis showing "possible value" instead of "visible value" ?
Here the graphs do not talk because they are not related to the min and max values.

Aquilon

That's done...

Stéphane

olnico

Dave, the 2.4 RF link uses its own transmission scheme. The data stream is transmitted in low energy to the Tx antenna that will translate it to its own "language". So choosing PPM or PCM in terms of what is better is irrelevant.
However, the following can be said:

The PPM/PCM choice will influence the number of channel available, depending on the radio maker.
For example, the JR 10x will get 9ch in PPM and 10ch in PCM.

In PCM there are 25 source frames, whereas in PPM there are 50 source frames. So the PPM mode will be more precise ( if you can feel the difference between a signal that is updated 50 times per second instead of 25 times ). However the PCM mode will be more robust since the PPM transmission will have 50 redundant frames, whereas the PCM one will have 75 redundant frames.