Myth busting Tello start order.

Guorium · Mar 13, 2019

I have seen some people mention that you should start tello and other equipment in a particular order with mitigate video stutter. It goes like

-repeater
-connect bt controller
-start Tello

The argument is that Tello chooses the least crowed wifi channel on boot-up and stays on that channel til you power it off. Turning it on last can avoid channels already occupied by the equipment turned on before. It is true but not the whole picture.

The most used xiaomi 2 repeater chooses channel 1 on startup no matter what. The kobwa extender chooses whatever channel it remembers last time no matter what. As long as they connect to tello they will shift channel to whatever Tello is selecting. So no matter what start sequence you use, they will always have the same channel (not ideal but it is what it is). In fact it could be bad to start tello after repeater since repeater will always take a fixed channel which could actually be free, giving tello less choices. (idea of @raulvolador ). If you fly in a park with no wifi at one end and crowed wifi at the other end, ideally you should start tello at the crowed end so it selects a channel that is best for the crowded end of the park and also works nicely for the free end of the park.

I personally use t1d controller which has BLE 4.0 protocol featuring adaptive frequency hopping. It avoids channels are already crowed then make signal jump very fast from frequency to frequency as a measure to reduce interference with wifi operating on the same frequency range. BT master (your phone) determines what bt algorithm to use when connecting to BT salve (controller). If both master and slave supports BT 5.0 then the algorithm avoid bad channels on the fly (good if you have varying interference), if one is BT 4.0 then you use the algorithm that makes a fixed list of bad channels to avoid upon connection. Not an issue given you might just have fixed interference if you stand on one place. For example, my iphone X is bt5.0 and t1d is bt4.0 so I should connect t1d last so it avoids the repeater&tello wifi channel. If I use a bt5.0 controller then it might not matter when I connect to my iphone.

So to sum it up, if anything, turn on your Tello first, controller last!

raulvolador · Mar 14, 2019

I agree with you. Generally It's better turning on Tello first, rest of equipment (repeater, etc.. ) last. I use to do that way.

Only exception is when I want Tello choosing a different WIFI channel. I turn on my Wifi Deauther first, filling WIFI spectrum of fake networks, then turn on tello at second place. That way I know Tello will not choose any of that crowded channels. Of course Wifi Deauther turned off before flying.

More details here: Tello WIFI channel selection

Raul.

Guorium · Mar 14, 2019

raulvolador said:
I agree with you. Generally It's better turning on Tello first, rest of equipment (repeater, etc.. ) last. I use to do that way.

Only exception is when I want Tello choosing a different WIFI channel. I turn on my Wifi Deauther first, filling WIFI spectrum of fake networks, then turn on tello at second place. That way I know Tello will not choose any of that crowded channels. Of course Wifi Deauther turned off before flying.

View attachment 3460 View attachment 3461

More details here: Tello WIFI channel selection

Raul.

don't trust tello's own decision?

raulvolador · Mar 14, 2019

Guorium said:
don't trust tello's own decision?

Correct. That's the key. Tello channel decision it's only based on nearby WIFI scanning. It can happen channel choosed by Tello it's heavy crowded one hundred meters away ruining your flight sesion at long distance. As I use to flight same place I flew long time ago at every WIFI channel and know what channel is giving me better performance.

Of course, if I'm going to fly at new places I let Tello makes it's own decision about best channel.

Guorium · Mar 14, 2019

raulvolador said:
Correct. That's the key. Tello channel decision it's only based on nearby WIFI scanning. It can happen channel choosed by Tello is heavy crowded one hundred meters away ruining your flight sesion at long distance. As I use to flight same place I flew long time ago at every WIFI channel and know what channel is giving me better performance.

Of course, if I'm going to fly at new places I let Tello makes it's own decision about best channel.

Cool. I don’t fly over urban. Just in parks, can take off in wifi crowed area to get a good channel then walk to in less crowded part of the park and fly the entire park. Tbh there is no single channel that is going to constanty work, neighborhood probably has every channel croweded.

Ansia · Mar 14, 2019

raulvolador said:
Correct. That's the key. Tello channel decision it's only based on nearby WIFI scanning. It can happen channel choosed by Tello it's heavy crowded one hundred meters away ruining your flight sesion at long distance. As I use to flight same place I flew long time ago at every WIFI channel and know what channel is giving me better performance.

Of course, if I'm going to fly at new places I let Tello makes it's own decision about best channel.

So what channel do you like your Tello flying at? 12+?

raulvolador · Mar 15, 2019

@Ansia,

Well, this is not a matter of "good" against "bad" channels

Best channel choice changes from time to time and from place to place. It totally depends channel usage of your neighbors WIFI's. In fact, when flying at countryside channel choice doesn't matter at all.

From my experience, at residential areas WIFI more crowded channels use to be Channel 1 (one), Channel 6 (six) and Channel 11 (eleven). This happens becouse they are recommended channels for WIFI routers due non overlapping, as said here Why Channels 1, 6, and 11? | MetaGeek

I advise you avoiding such 1, 6, and 11 crowded channels. Tello use to avoid them by itself. What I use to do is using my Wifi Deauther trick ( Tello WIFI channel selection ) forcing Tello changing their choice from lower gap channels numbers 3-4 to high gap channels numbers 8-9. I have found that in my area these channels, especially channel nine, are giving me best performance, less interference and more range. I suposse channel 13 can be a good bet, but I have not yet been able forcing Tello to choose it. Unfortunatelly channel 14 is not available at my country.

I hope this picture clarify my words:

All the best.

Raul.
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umanbean · Mar 15, 2019

raulvolador said:
Well, this is not a matter of "good" against "bad" channels

Great explaination, thanks!

Walleye · Mar 21, 2019

raulvolador said:
I agree with you. Generally It's better turning on Tello first, rest of equipment (repeater, etc.. ) last. I use to do that way.

Only exception is when I want Tello choosing a different WIFI channel. I turn on my Wifi Deauther first, filling WIFI spectrum of fake networks, then turn on tello at second place. That way I know Tello will not choose any of that crowded channels. Of course Wifi Deauther turned off before flying.

View attachment 3460 View attachment 3461

More details here: Tello WIFI channel selection

Raul.