900 MHz Band, Would Autel Listen to an Owner Petition?

[G_G]

Dont be jelly just because you're an older model.

I was ascribing wisdom to you beyond your years!

 

[thomasr]

I would be nice if there was a switch to turn off the 900 MGz radio and just use the 2.4 GHz transmitter should there be other traffic on that frequency in that area.

It's probably too much to ask, but if it would show 900 MHz traffic on the explorer graph as it does now for the 5, 10, 20 settings option it wouldn't be too hard to see if there is traffic. That graph is good for that at least.

The biggest plus for 900 MHz is that it is referred to as "Near Line of Sight or NLoS" -- This means you get better range than the other bands available given the same obstructions. The drawback for more range is that you have less bandwidth than you have at 2.4 GHz or 5.8 GHz.

The most important thing to remember though in working with 900 MHz is that you must know what other 900 MHz systems may be using the same spectrum in the area. Depending on the frequency scheme at 900 MHz, it is easy to "walk" over other systems.

The 900 MHz band has only 26 MHz of bandwidth, compared with ~83 MHz in 2.4 GHz, and ~160-200 MHz in 5.8 GHz systems - all depending on the channel bandwidth chosen like the Autel's current 5,10,20 settings. So on 900 Mhz you just can't pull as much data through this link as you can with 2.4 Ghz or 5.8 Ghz.

Typically, the limit seems to be around 10-20 mb/s of net data throughput, and much less if you're pushing the envelope as to range, obstacles, or local interference.

This means while there may be the option to run 900 MHz and get farther range - the data and video stream will be so limited if not useless once you get so far.

Autel's 5,10,20 would apply to 900 MHz -- but in practice -- you can really only expect 5 or 10 MHz to work. You will usually find the right combination of range, obstacle or local interference - license holder or consumer device like a baby monitor or antique 900 MHz phone - will be just enough to make 20 MHz unstable or just totally unreliable.

 

[G_G]

The biggest plus for 900 MHz is that it is referred to as "Near Line of Sight or NLoS" -- This means you get better range than the other bands available given the same obstructions. The drawback for more range is that you have less bandwidth than you have at 2.4 GHz or 5.8 GHz.

The most important thing to remember though in working with 900 MHz is that you must know what other 900 MHz systems may be using the same spectrum in the area. Depending on the frequency scheme at 900 MHz, it is easy to "walk" over other systems.

The 900 MHz band has only 26 MHz of bandwidth, compared with ~83 MHz in 2.4 GHz, and ~160-200 MHz in 5.8 GHz systems - all depending on the channel bandwidth chosen like the Autel's current 5,10,20 settings. So on 900 Mhz you just can't pull as much data through this link as you can with 2.4 Ghz or 5.8 Ghz.

Typically, the limit seems to be around 10-20 mb/s of net data throughput, and much less if you're pushing the envelope as to range, obstacles, or local interference.

This means while there may be the option to run 900 MHz and get farther range - the data and video stream will be so limited if not useless once you get so far.

Autel's 5,10,20 would apply to 900 MHz -- but in practice -- you can really only expect 5 or 10 MHz to work. You will usually find the right combination of range, obstacle or local interference - license holder or consumer device like a baby monitor or antique 900 MHz phone - will be just enough to make 20 MHz unstable or just totally unreliable.

Good info! Can you clarify the meaning and proper use of the three Broadband Settings of 5, 10, 20 Mhz, and the three Image Transmission Modes of Normal, High Definition, and Smoothness? Which settings will give most reliable signal and video feed at long range?

 

[Ansia]

Good info! Can you clarify the meaning and proper use of the three Broadband Settings of 5, 10, 20 Mhz, and the three Image Transmission Modes of Normal, High Definition, and Smoothness? Which settings will give most reliable signal and video feed at long range?

Normal is the one you want.

 

[G_G]

Normal is the one you want.

What about the 5, 10, 15 selection?

 

[Apollo11capcom]

This means while there may be the option to run 900 MHz and get farther range - the data and video stream will be so limited if not useless once you get so far.

What exactly do you mean by range if data and image transmission are limited/useless? I'm confused, the data and image transmission is exactly what I thought we were increasing the range for... ?

 

[Ansia]

What about the 5, 10, 15 selection?

10. In theory 5 should get you farther, but test done by some have prooved this not to be true.

 

[Apollo11capcom]

10. In theory 5 should get you farther, but test done by some have prooved this not to be true.

This is fact. The last time I tried 5, I got the weak video signal before I even lifted off, I was standing right next to it too. The 5 option seemed pretty darn useless at that moment.

 

[Madhungarian]

This is fact. The last time I tried 5, I got the weak video signal before I even lifted off, I was standing right next to it too. The 5 option seemed pretty darn useless at that moment.

I used the 5 option the other day and was getting weak signal but even 1.2 miles out I did not loose video. I believe you need to have it set to smooth, any other setting will give you weak signal warnings.

 

[thomasr]

What about the 5, 10, 15 selection?

This is a snip from their test documentation on file with the FCC -- these are the data rates for the different modes.

It was mentioned in a previous discussion about a 3M mode being mentioned... this has more to do with 900 MHz and may be an option for 2400 MHz in China -- since they are so crowded. I am not sure - but do not think it is an option in the US - our wireless channels are 5,10,20,40,80,160 mhz wide depending on 2.4 Ghz or 5.8 GHz.

In my experience "DATA RATE" means a "CHANNEL RATE" and is never what you actually get -- after such things as link overhead and compression schemes used, you may get just at or over half the listed data rate.

They may be using H.264 compression on the video stream. This would reduce the bandwidth required to send each different level of video quality This I do not know - i haven't read all of their documentation -- and may not even be listed.

If this were the case it would be Smooth: ~2-3 Mbps Normal: ~4-5 Mbps High Definition: ~6-7 Mbps

 

[Apollo11capcom]

I used the 5 option the other day and was getting weak signal but even 1.2 miles out I did not loose video. I believe you need to have it set to smooth, any other setting will give you weak signal warnings.

This is a good point. I've seen the warning a number of times when getting far out there, but I've never lost video signal, ever. As a matter of fact, I've never even seen a blip of distortion.

Maybe this will be my next test... totally ignoring the warning messages, and seeing how far I can actually go before I have loss of signal. I've got some great farm land to use for this where there's miles to work with. Worst case scenario, if I lose connection, it'll come home.

I'll keep it on a straight line as well, so if I run out of juice before I get back, it'll emergency land along that line. Not that I want that to happen, but if it does I'll also have a chance to test the drone locator on the map.

 

[G_G]

10. In theory 5 should get you farther, but test done by some have prooved this not to be true.

I'll definitely try that, as I have been getting constant weak video messages, video lag, and complete video drop outs at over a mile, while the control signal extends to well over 3 miles without any RTH signal loss,. Autel has so far been of no help in that regard. I begrudgingly accepted that that was all I could expect. Hopefully, this will help!

 

[G_G]

This is a snip from their test documentation on file with the FCC -- these are the data rates for the different modes.

It was mentioned in a previous discussion about a 3M mode being mentioned... this has more to do with 900 MHz and may be an option for 2400 MHz in China -- since they are so crowded. I am not sure - but do not think it is an option in the US - our wireless channels are 5,10,20,40,80,160 mhz wide depending on 2.4 Ghz or 5.8 GHz.

In my experience "DATA RATE" means a "CHANNEL RATE" and is never what you actually get -- after such things as link overhead and compression schemes used, you may get just at or over half the listed data rate.

They may be using H.264 compression on the video stream. This would reduce the bandwidth required to send each different level of video quality This I do not know - i haven't read all of their documentation -- and may not even be listed.

If this were the case it would be Smooth: ~2-3 Mbps Normal: ~4-5 Mbps High Definition: ~6-7 Mbps



View attachment 4006

So Smooth would be most likely to retain some level of video signal at long range, as in lowest quality, but not losing video for lack of enough signal strength?

 

[G_G]

This is fact. The last time I tried 5, I got the weak video signal before I even lifted off, I was standing right next to it too. The 5 option seemed pretty darn useless at that moment.

That was my experience as well!

 

[G_G]

I used the 5 option the other day and was getting weak signal but even 1.2 miles out I did not loose video. I believe you need to have it set to smooth, any other setting will give you weak signal warnings.

Those "weak video signal" messages are more pervasive and annoying than the high wind warnings on DJI aircraft, and just as useless. Once you have notified me and I dismiss it, stop being such a nag, and continuously repeating them, blocking my FPV, and let it go! If the video goes out, I'll see it soon enough. If the wind is high, I clearly know it already! I complained to Autel about the weak video messages that won't go away, and they have no desire to remove the weak video on the screen! If I could avoid them altogether with the best video setting, I'll be in EVO heaven!

 

[thomasr]

So Smooth would be most likely to retain some level of video signal at long range, as in lowest quality, but not losing video for lack of enough signal strength?

Correct. And I finally found this covered in the video -- I knew I had seen it somewhere -- I just didn't know if it were actual Autel or someone testing their drone for us on YouTube.

Edit: Not sure, but I think you can select 10 and Smooth... I don't think that reverts the first selection back to 5 -- just leaves it on the 10 channel width and sends a lower resolution feed.


Actually Autel:

 

[Apollo11capcom]

Actually Autel:

Well I'll b darned, they changed it from 5, 10, and 20 MHz to 5, 10, and 20 Mbps!

 

[G_G]

Correct. And I finally found this covered in the video -- I knew I had seen it somewhere -- I just didn't know if it were actual Autel or someone testing their drone for us on YouTube.

Edit: Not sure, but I think you can select 10 and Smooth... I don't think that reverts the first selection back to 5 -- just leaves it on the 10 channel width and sends a lower resolution feed.


Actually Autel:

Smooth and 10 it shall be! Not very clearly explained in the video though.

 

[Rofl it's Waffle]

Isn't 900 MHz is a fairly crowded frequency? It's the home of AM Radio and private phone communication.

 

[G_G]

Isn't 900 MHz is a fairly crowded frequency? It's the home of AM Radio and private phone communication.

Hardly anyone listens to AM radio any more, but the 900 Mhz band is used by first responders, and the military, because it is so effective. auto frequency hopping within the band is the key. As long as there is a clear frequency at the location of the RC, the drone is generally continuously in motion, so sporadic interference isn't a problem, especially when backed up by the 2.4Ghz band.