How to: Avoid loss of controller connection and WiFi Interference

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I'd like to share realistic thoughts on how to keep a solid connection with the Solo. The following is from information that I learned and from my own RF experiences.

One thing we know is that with the current firmware (version 1.05) the Solo will only use only WiFi channels 6 or 11 for communications (this was confirmed via a 3DR email). This could change in the future, but it's what we have now. EDIT: Later firmware added the ability to use other WiFi channels in addition to only 6 and 11.

Screenshot_2015-07-10-16-00-48.png

As you can see in the image, the Solo is currently on WiFi channel 6. You can also see that each WiFi channel overlaps others. So it's possible for WiFi devices to interfere with each other if there is a close by strong signal to the Solo channel, even if it's not exactly on the Solo's channel. With normal WiFi, the bandwidth will go down with crowding and interference. I'm sure this will affect the Solo to one degree or another.

I'd like to suggest that people use their smart phone and get a WiFi scanner app to check the WiFi environment before you fly. This is the one that I'm using, it's free for Android:
WiFi Analyzer by farproc
I'm not saying this is the only one, or the best one, but it's one that I've been using for a few years now.
If someone knows of a similar app for the Apple devices, please let us know.

If you like, you can also scan the WiFi channels after you turn on the controller, as this will let you know what channel the controller chose.

The first thing to check is to see if there are any strong WiFi signals on or near Channels 6 or 11. By strong, I'd say anything -70 dbm or stronger (on the dbm scale, a smaller number is a stronger signal, so -60dbm is 10 dbm stronger than a -70 dbm signal, a -50 dbm signal is a fairly strong signal). If there are strong signals on other channels, the further they are from channels 6 or 11, the better (actually, the further they are from the channel that the controller chose is the best). For example if your Solo is on channel 6, and there is a -60 dbm signal on channel 5, then you may expect to see interference. But if that -60 dbm signal was on channel 1, it may not bother you so much.

Keep in mind that this is not absolute! Remember that you are standing on the ground at one point and surveying the WiFi signals where you are located. As your Solo flies around, it will see other signals that you don't see on the ground. It will also see varying signal strengths from other signals as it's flying about. It can also see signal reflections that can cause problems too. As it gets further from you, it could see signals that can't be seen at all from where you are located. In short, It's a complicated WiFi jungle out there!

Perhaps we can get some data on the WiFi environments that we know will work, or what we know won't work. I think it's a bit vague for 3DR to only say "don't fly in a crowded WiFi environment", but I can understand why they only say this. The average person won't have a clue as to how to figure out what may or may not work, even after reading a document like this. ;)

I'd like us to be successful with the stock antennas, and understanding the WiFi environment around us, and the possible channels that Solo will use will help us a lot.

Later on, we can document and experiment with other antennas and other things that may help.

If I think of other things, I'll either edit this post, or reply to it, as appropriate.
 
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Thanks Rich,

I just bought my first Android phone (LG G4 - my iPhone 5 wasn't compatible with the Solo app, and showing it's age anyway). I live in a concrete highrise on the 24th floor and was amazed at how many signals are interfering with my home wifi. Great app, and article, thanks for sharing buddy.
 
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Wifi explorer is another decent app I tried both and this one seemed to pick up a few more signals near me at least and showed some that were hidden. They basically are the same if I remember right I just picked this one from the couple spots I tested near me.

Also Sam or solar activity monitor seems like a very simplified easy to check tool to use as well. There's not a lot of info but when it says there's high solar activity I have noticed more drift and had some issues. Could be coincidence or not but its worth the two seconds it takes to check it for me. I usually don't decide against flying if it says there's activity but I just try to be a little better prepared for issues, one night it said storms and flares were very active and my solo and p3 were both going nuts so I grounded both but that's the only time I've actually not flown.

Great write up, these in my mind are both valuable tools to have so you at very least know what your getting yourself into interference wise. Solo especially does seem more sensitive to these things than other quads I've flown.
 
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This is a timely topic for me. You say channels 6 and 11 are used. Is one for control and the other video?

We are planning a WiFi test this weekend due to the various flyers at our field. Good info to know.
 
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Unless something has changed recently, many years ago Apple pulled the plug on apps that scan for wifi and display this type of info. I use these apps quite often and it was one of the biggest reasons I ran from Apple to Android and haven't looked back.

Sorry to say, if you have an Apple device, you're probably out of luck. :(
 
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Unless something has changed recently, many years ago Apple pulled the plug on apps that scan for wifi and display this type of info. I use these apps quite often and it was one of the biggest reasons I ran from Apple to Android and haven't looked back.

Sorry to say, if you have an Apple device, you're probably out of luck. :(

You are right. Only Mac OS will allow access to WiFi data. I'm digging up my old Droid just for this feature.
 
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I wonder why 3dr limited it to only two channels. And what is the deal with DJI using 13-20?
 
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I wonder why 3dr limited it to only two channels. And what is the deal with DJI using 13-20?

Had a P3 pro next to me this weekend. He was going out more than a mile whereas I could only get 1500 feet or so. Does the P3 use 2.4 for control and video?
 
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Yes, 2.4 just like the Solo.

I can fly my Solo to about 4400' easily from a spot I commonly fly. I can land it and fire up my P3 and go over 8500 in the same spot.
 
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Yes, 2.4 just like the Solo.

I can fly my Solo to about 4400' easily from a spot I commonly fly. I can land it and fire up my P3 and go over 8500 in the same spot.

Ok so what is going on. Is it the channels used for P3 as you mentioned (13-20) or is the antennae directional on the P3?
 
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P3 uses similar vertical radiator antennas. Its not the antennas that are making the range. DJIs lightbridge setup just handles range way better than the Solo.

I really dont know why. I do know that the DJI uses channels 13-20. I have mine locked clear up at 20 where there is no traffic.

Maybe someone will chime in. I really don't understand where the 13-20 comes in as that is outside the standard 802.11 band.
 
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i had my share of issue connecting the controller to the solo and this in my basement i send a ticket to 3dr and they didn't find the reason why it can't connect yet

But after looking at the root/etc/hostapd.com there's a line that talk about "chanlist" and channels 6&11
was default 3DR

So i had to add more channels so i change chanlist and add "4 5 6 7 8 9 10 11" no quotes

now it connect no isssues and never had controller signal lost since

3DR reply

The developers informed me that there must be some strange WiFi issue at your place that is causing the Solo to behave like that.
They looked at the info you sent including your last email and this is what they mentioned:

"Regarding the channels, we found that there is more interference if there is a noise source on an adjacent channel. For example, if Solo is on channel 7 and your home WiFi is on channel 6, then there will be more interference than if they are both on channel 6. This is because when both systems are on channel 6, then they can negotiate sharing the channel, but when they are on adjacent channels they interfere with each other because they are on similar frequencies but have no way of negotiating sharing.

The vast majority of home WiFi access points operate on channels 6 and 11, that’s why we chose them.

This customer can use the “Wifi Analyzer” Android app, or similar, to measure what level of interference is present on each channel, to better understand what weirdness is going on at his home.

The development team is really busy right now with the Gimbal testing and they apologize for the long wait.
I encourage you to keep experimenting and feeding us back the data you gather so I can send it to the developers.
They will look into it as there is time.

Also, please keep flying on open areas and let me know if you find any oddity so I can report it.

Let me know if you have any questions.

Best regards
 

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Commenting out the chanlist parameter should have the channel autoselected, but I haven't tested it.

You'll also need to run md5sum /etc/hostapd.conf > /etc/hostapd.conf.md5. This was information provided in the FB mod page. Without it the changes are ignored.

Both Solo and controller need to be changed.
 
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yes i had to edit boths the controller 10.1.1.1 and the solo 10.1.1.10

at the end you need to run md5 so the solo and the controller keeps your modifications
if your inside root/etc/ here's the syntax: md5sum hostapd.conf > hostapd.conf.md5

This solo forums should have sticky topics that will be great
 
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Commenting out the chanlist parameter should have the channel autoselected, but I haven't tested it.

You'll also need to run md5sum /etc/hostapd.conf > /etc/hostapd.conf.md5. This was information provided in the FB mod page. Without it the changes are ignored.

Both Solo and controller need to be changed.
Which mod page are you talking about. I might not have found this one yet :)
 
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I wonder why 3dr limited it to only two channels. And what is the deal with DJI using 13-20?

This was 3DRs response as to the Solo only using channels 6 and 11:
The Solo only jumps between channels 6 and 11; yes, this is by design as those two channels do not touch in regards to bandwidth
Crowded wifi (all RF noise in general) would mostly consist in largely populated areas where several WiFi networks may cause interference and cutting range to the solo dramatically.
This does not entail specific channels as most wifi networks (regardless of the channel) would overlap to some degree on the solo's broadcast.

As to DJI using channels 13-20, where is this info? As far as I can see, these may not be channels allowed in the USA as North America only lists channels 1 through 11: https://en.wikipedia.org/wiki/List_of_WLAN_channels

Note that even this Wiki lists the only non-overlapping channels as 1, 6 and 11 (which was hinted to by 3DR).

This may explain why other higher 2.4 channels are not used (from the wiki):
A Federal Communications Commission (FCC) document clarifies that only channel 14 is forbidden and furthermore low-power transmitters with low-gain antennas may legally operate in channels 12 and 13.[13] However, channels 12 and 13 are not normally used in order to avoid any potential interference in the adjacent restricted frequency band, 2,483.5–2,500 MHz

Here is a link that shows the allocations at the higher frequencies: http://www.spectrumwiki.com/wiki/display.aspx?f=2483500000

So I'm not sure how DJI is getting away with higher 2.4 GHz channels. Where does your info come from? From what I can see in the specs, they are using the normal 2.4 GHz RC spread spectrum frequencies:
http://www.dji.com/product/phantom-3/spec says:
Operating Frequency
2.400 GHz-2.483 GHz

Which seems like the normal frequency range for RC 2.4 GHz spread spectrum operation. So I'm guessing that DJI is using RC type of spread spectrum for 2.4 GHz (which I find is not often bothered by WiFi signals, unless they are very strong), where I believe that the 3DR Solo is using all control and communications via the WiFi protocol (but I could be wrong).

I didn't want this thread to get into yet another "compare the Solo to DJI thread", I'd prefer it to stay fairly fact based on how we can understand the Solo system to help us be more successful with it.
 
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