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WIFI+S Range Extender vs Xiami WIFI Repeater and Tello Channel choice

raulvolador

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Also, I’d say probably have location and cellular data (you can test these two settings individually) enabled for the oem app and connect to tello, shut tello, start wifi deuther, start tello and connect to oem app. Then perform you wifi analysis.
I did it. Unfortunatelly it didn't work :(

Wifi channels 12 and 13 are unreachable for Tello even I previously entered stock OEM Tello app for proper region initialization.

As @volate!lo said, it looks a dead end street.

Forum's guru help needed here to give us any tool for asking/setting Tello region.

Raul.
 

Guorium

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I did it. Unfortunatelly it didn't work :(

Wifi channels 12 and 13 are unreachable for Tello even I previously entered stock OEM Tello app for proper region initialization.

As @volate!lo said, it looks a dead end street.

Forum's guru help needed here to give us any tool for asking/setting Tello region.

Raul.
Ok thanks for testing! Maybe there is something on controller side then. Vola is doing some good reading on "set wifi power". I am querying the hopeless ryze support for an answer. According to your result, I suppose we can say tello really has just a fcc mode I think?
 
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volate!lo

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I will provide a (secret) way to query location in the next version.
However without seeing the "set region" command in action I can't provide a way to support that. But I just received a brand new Tello so maybe I get a chance for seeing the initial setup process in action.
 

raulvolador

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I will provide a (secret) way to query location in the next version.
However without seeing the "set region" command in action I can't provide a way to support that. But I just received a brand new Tello so maybe I get a chance for seeing the initial setup process in action.
Cool !

That query location is just what we need to continue our quest.

I hope you are lucky initializing that new tello. Your fleet is growing ;)

Raul.
 

Guorium

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I will provide a (secret) way to query location in the next version.
However without seeing the "set region" command in action I can't provide a way to support that. But I just received a brand new Tello so maybe I get a chance for seeing the initial setup process in action.
hmmmm would the initiation be different from later resets? Tello should have the capability to switch region on the fly if there are indeed different power compliance like the manual states.
 

volate!lo

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I hope you are lucky initializing that new tello. Your fleet is growing ;)
Actually its shrinking :eek:

I have wrecked two in the last weeks.


hmmmm would the initiation be different from later resets? Tello should have the capability to switch region on the fly if there are indeed different power compliance like the manual states.
No clue. All I can say is that I haven't seen _any_ local initialization taking place so far.
 
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Guorium

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Actually its shrinking :eek:

I have wrecked two in the last weeks.



No clue. All I can say is that I haven't seen _any_ local initialization taking place so far.
Local initialization as in the oem app telling tello to set certain region?

On iphone i am advised that tello app used location data if I permit it. If it does not inform tello about this info then it maybe using this info for itself. My guess is setting phone transmitter power.
 

volate!lo

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Local initialization as in the oem app telling tello to set certain region?

On iphone i am advised that tello app used location data if I permit it. If it does not inform tello about this info then it maybe using this info for itself. My guess is setting phone transmitter power.
There is -at least under android- no way of setting transmitter power of the phone. The app can either use that information to "register" the drone (send your position and serial number to china).
Or to set the region code of Tello (which I haven't seen so far). We shall see in a few hours when I finished my current work on bitrates to make Raul happy , so I can switch over to analyzing the initialization process.
 

raulvolador

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There is -at least under android- no way of setting transmitter power of the phone. The app can either use that information to "register" the drone (send your position and serial number to china).
Or to set the region code of Tello (which I haven't seen so far). We shall see in a few hours when I finished my current work on bitrates to make Raul happy , so I can switch over to analyzing the initialization process.
Sure, I'm feeling very happy today ;)

Thanks a lot, @volate!lo
 

volate!lo

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I just did my experiments (which implies that Raul's bitrate thing is done).
No luck.
I checked the region codes of all Tellos around: 3x "US", 1x "DE" and my brand new one which has not yet received any firmware updates reports "FF".

DE would make sense, everything else not so much. I have deleted and reinstalled a couple of times. It asked me for "activation", and access to my location. I tried with and without granting the app access to the location. I tried ecverything I could. Not once was the region set.
My brand new Tello still says "FF". The only thing thats left to try is a firmware update but I am not going to do this.

Because this Tello with old firmware has a few nice features:
It is much faster in slow mode, it has better attitude angles in low altitude, Sport mode seems unaffected by altitude, and the best thing: More flight time!
My first flight with this Tello the drone initated autolanding once but this can be cancelled. After cancellation it does not enforce autolanding a few seconds later like the current firmware does. It just keeps flying until it starts to behave erratically at around 2% battery.
Cool !


But bottom line: This is a dead end for now
 
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raulvolador

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I just did my experiments (which implies that Raul's bitrate thing is done).
Happy, happy, happy.... you makes me happy :D:D:D

No luck.
I checked the region codes of all Tellos around: 3x "US", 1x "DE" and my brand new one which has not yet received any firmware updates reports "FF".
Very interesting and detailed test. Congratulations. At least you discovered Tellos with different region code set: 'DE' it's supposed to be Germany, 'US' United States and I have no idea what 'FF' means.

We should wait for your anounced 'secret' way to query location into the next version and maybe among all we can discover something more.

Raul.
 
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raulvolador

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Because this Tello with old firmware has a few nice features:
It is much faster in slow mode, it has better attitude angles in low altitude, Sport mode seems unaffected by altitude, and the best thing: More flight time!
You've convinced me .

If I buy another Tello I will not update the firmware, like you ;)

Raul.
 

Guorium

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I just did my experiments (which implies that Raul's bitrate thing is done).
No luck.
I checked the region codes of all Tellos around: 3x "US", 1x "DE" and my brand new one which has not yet received any firmware updates reports "FF".

DE would make sense, everything else not so much. I have deleted and reinstalled a couple of times. It asked me for "activation", and access to my location. I tried with and without granting the app access to the location. I tried ecverything I could. Not once was the region set.
My brand new Tello still says "FF". The only thing thats left to try is a firmware update but I am not going to do this.

Because this Tello with old firmware has a few nice features:
It is much faster in slow mode, it has better attitude angles in low altitude, Sport mode seems unaffected by altitude, and the best thing: More flight time!
My first flight with this Tello the drone initated autolanding once but this can be cancelled. After cancellation it does not enforce autolanding a few seconds later like the current firmware does. It just keeps flying until it starts to behave erratically at around 2% battery.
Cool !


But bottom line: This is a dead end for now
Thank you for your big big contribution to the investigation. In order the properly interpret the results from you I would like some help to clear up some terms you use.

1. What do you mean by query location? Do you query the oem app or tello?
2. What do you mean by "set tello to a region"? Does tello get told a region by the oem app and keep that info onboard but does not show any signs of altering transmission protocol?
3. How did you end up with 3 US and 1 DE assuming tello does store region info on itself?
4.
Interesting. So somehow I missed this "set wifi power" message duing startup. I will check again.
Did you follow up on this? If tello does change transmission power, it maybe possible that "set wifi power" message on startup is doing something?

I doubt if a 3rd party app has the control over phone's RF hardware too, besides the transmission compliance in the manual was for tello clearly. I will continue with Ryze support to find out what they know about the matter (oh the frustration haha).

For @raulvolador , I have seen repeated F in color code when it is undefined so FF probably means null.

I read the FCC report for tello. They made a test program on page 6 for the compliance test to stream data at test frequencies (1,6,11channel). Only 11 channels were provided since it was the FCC test. Chain 1/0 means horizontal/vertical polarization. On page 11 they show tello's calculated max antenna gain which is 2.96dbi. On page 44 they show the test result for the program (tello was running the program with antenna removed and RF spectrometer connected via low loss cable). All this gave us an EIRP of 2.96 + 16.83 (max avg conducted power in g mode wifi which tello operates on) = 19.79dbm. Fairly close to what the manual claims for FCC (20dbm). I am seeking the CE report now (from Ryze) which isn't open accessible on the internet like the FCC report.

I found the Chinese certification on Chinese authority CMIIT website after checking the certification IDs printed in the battery bay of tello. They got two records for tello for some reason but they are identical. If you click into one of them you see. (Also I found cert ID for Korea, Taiwan, Brazil, Cananda and unknown code 2T1-180101 printed on Tello)
3564

The EIRP quoted here has a max of 20 compared to 19dbm the manual claims under SRRC (FCC/CE equivalent of China).

I organised some countries 2.4Ghz wifi tranmission power limit and linked relevant documentation for evidence.
Region (Authority)Tello CertificationRyze claimed power (EIRP)Compliance report power (EIRP)Compliance limit power (EIRP)Allowed WiFi Channels
US (FCC)FCCID 2AOOE-WM004180120dbm19.79dbm (avg) 26.29dbm (max)36dbm1-11
Europe (ETSI)CE (ID not found)19dbmNot found20dbm1-13
China (SRRC)CMIIT ID 2018DP007719dbm20dbm (probably the US report avg figure rounded up)20dbm1-13
Australia (ACMA)RCM (ID not found)N/AN/A36dbm1-13

As we can see from the table, Tello clearly is well under the FCC limit given the test program even with the max EIRP. Both China and EU has the same max limit at 20dbm. I argue that since Ryze claimed 20dbm for FCC which is close to their average report figure. They would have gone with the average report figure for EU and SRRC as well. In fact in both CE (Page 49) and FCC (d), a maximum average (RMS) conducted output power is to be used for digital modulation transmitter (WiFi is). I have reasonable ground to believe tello meets the CE and SRRC test limits with the more power liberal FCC report test. In the FCC test we also witness Ryze has the ability to tune the transmission power via software. There is a very small chance that Ryze utilized different output power program in the CE test (if it took event at all), but to prove it Ryze must agree to offer me a CE test report. So this wild goose chase seem to have most likely been caused by an innocent typo made by whoever compiled the manual at Ryze. I am gonna wait and see if the CE report says something interesting if they give me.
 
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raulvolador

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For @raulvolador , I have seen repeated F in color code when it is undefined so FF probably means null.
I agree with you

This wild goose chase seem to have been caused by an innocent typo made by whoever compiled the manual at Ryze.
Yes, those Wifi power differences 19db vs 20db between FCC and CE regions seems a typographic mistake or math rounding error, since laboratory report value is 19.79db.

I read the FCC report for tello. They made a test program on page 6 for the compliance test to stream data at test frequencies (1,6,11channel). Only 11 channels were provided since it was the FCC test...I found the Chinese certification on Chinese authority CMIIT website ... Also you see here China allows up to 13 channels too.
Very impressive research. I'm very surprised you couldn`t find CE report for Tello. That's the key to clarify if Tello can access 12th and 13th wifi channels when set that region.

Raul.
 
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Guorium

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I agree with you



Yes, those Wifi power differences 19db vs 20db between FCC and CE regions seems a typographic mistake or math rounding error, since laboratory report value is 19.79db.



Very impressive research. I'm very surprised you couldn`t find CE report for Tello. That's the key to clarify if Tello can access 12th and 13th wifi channels when set that region.

Raul.
I tabulated the results with documentations linked. Maybe region just limits channel 12 and 13 for US and keeps power unchanged. CE report is not openly accessible online sadly, if tello genuinely has CE certification then Ryze should be hold the CE report and it is only up to them to decide if they offer a copy to me.
 
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raulvolador

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I tabulated the results with documentations linked. Maybe region just limits channel 12 and 13 for US and keeps power unchanged. CE report is not openly accessible online sadly, if tello genuinely has CE certification then Ryze should be hold the CE report and it is only up to them to decide if they offer a copy to me.
You performed a deep research. Good job ;)

Remember to share if you get Tello CE Wifi Certification document.

I hope Ryze is not cheating us, keeping a unchanged wifi power and a fixed one-to-eleven list of available channels whatever region set. If they do that for FCC, will they fulfill certification requisites for all regions ?
 
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volate!lo

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Thank you for your big big contribution to the investigation. In order the properly interpret the results from you I would like some help to clear up some terms you use.

1. What do you mean by query location? Do you query the oem app or tello?
2. What do you mean by "set tello to a region"? Does tello get told a region by the oem app and keep that info onboard but does not show any signs of altering transmission protocol?
3. How did you end up with 3 US and 1 DE assuming tello does store region info on itself?
4. Did you follow up on this? If tello does change transmission power, it maybe possible that "set wifi power" message on startup is doing something?

I doubt if a 3rd party app has the control over phone's RF hardware too, besides the transmission compliance in the manual was for tello clearly. I will continue with Ryze support to find out what they know about the matter (oh the frustration haha).
1) There is a command sent to Tello to query a region code from the drone. My Tellos report 3x US, 1x DE, and the brand new one is FF.
2) I have also seen a "Set Region" command somewhere, I think it was in Krag's TelloLib. But I have never seen when monitoring the byte stream between the ryze app and Tello. And I tried everything, including registration of the brand new tello. I also monitored the firmware update of one of my drones from the previous version to the current version, and the command wasn't used in this process, too. The only thing left is a firmware upgrade of the brand new drone, which I don't want to do. Since I only have the command, but not the parameters it accepts, I can't test it. I need to see the command being used before I can replicate it.
3) I have no clue. It could be that 3 of these were originally sold in the US (I bought three of my drones "used" from a big re-seller selling items returned to shops like Amazon, but I lost track which one is which). All I know is that the brand new one with FF came sealed from a german store
4) As said, I can see different regions reported, but I don't understand how to set the region. So I can't really follow up.
 

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