Controller Signal-Strength

[Rich]

I sent an email to my 3DR support contact asking how to evaluate the WiFI environment to know when it's safe to fly.

I know the Solo (bird in the air) will see a different WiFi environment than the controller (on the ground), but there must be some way to evaluate the environment to know if we will see issues or not.

I'm referring to interference here, not RF radio range.

I was surprised the other day, flying in what appeared to be an open field, not very close to buildings, there was a VERY strong WiFi signal. Come to find out it had the name of my friend on it (we used his car to drive to this field). He wasn't even aware that his car had a hot spot in it (not to mention that the hot spot SSID was his name!). We checked his vehical's menus and couldn't find a way to disable the WiFi hot spot in it. Luckily it seemed to turn itself off a couple of minutes after the car was shut off (it was a 2015 Chevy mini SUV).

So if the Solo is susceptible to WiFi interference, we certainly can't stop random cards from driving up, or someone showing up that has their phone in their pocket in a 'hot spot enabled' mode.

Perhaps 3DR can put a WiFi scanner into the controller to provide us with some sort of visibility into how crowded the WiFi environment is in the area to be flown? Or, they need to make the controller to Solo signal more robust and less susceptible to loss of signal?

FYI: I lost controller signal once when my Solo was VERY close to me (about 30 feet up / 30 feet out). Luckily it hasn't happened again, but I haven't flown it much since this loss of control happened.

 

[rrmccabe]

I honestly would be surprised if actual 802.11 wireless is causing issues. If so it's a serious design flaw with the bird as we will never be able to get away from it.

That said my Solo has never been launched from anywhere but my house. I have three wireless access points (basement, first floor, second floor) and have never had an issue with any of my Phantoms or the Solo yet.

 

[Seabee]

Returned my Solo to Best Buy last month. Really liked the way it flew( high disc loading) but controller/Solo range and GPS aquisition/lock issues were deal breakers. It appears that the low Controller/Solo transmit power(10 mW, 10 dBm I think) and a 2 dBi antenna give an EIRP that meets EU standards but is way below ( 24 dBm) US 2.4 gHz ISM band limits. The GPS antenna appears too close to metal in the craft. This does not help in receiving the weak 1.575 gHz L1 MEO GPS satellite signals or the L1 from the geosync WAAS satellites. Looks like design problems to me. Hope 3DR can get them corrected in a v2 Solo.
In the mean time, I am seriously considering purchasing the X8+.
Just some thoughts from a retired electrical engineer and corporate jet pilot.

 

[Lonewulph]

Returned my Solo to Best Buy last month. Really liked the way it flew( high disc loading) but controller/Solo range and GPS aquisition/lock issues were deal breakers. It appears that the low Controller/Solo transmit power(10 mW, 10 dBm I think) and a 2 dBi antenna give an EIRP that meets EU standards but is way below ( 24 dBm) US 2.4 gHz ISM band limits. The GPS antenna appears too close to metal in the craft. This does not help in receiving the weak 1.575 gHz L1 MEO GPS satellite signals or the L1 from the geosync WAAS satellites. Looks like design problems to me. Hope 3DR can get them corrected in a v2 Solo.
In the mean time, I am seriously considering purchasing the X8+.
Just some thoughts from a retired electrical engineer and corporate jet pilot.

-Seabee in your opinion of the gps location, would a magnetic field generated by the motors, which are mounted higher than the gps, cause interference?
-Can 802.11 wifi be hindered by other wifi sources? What other source can disrupt any level of wifi? RF?
-I remember Rich talking about the controllers constantly switch freqs to avoid conflict with other controllers, does solo do this switching in-flight if it hits a conflicting freq which in turn drops connection?
-Is proximity to cell towers a significant issue?
Thanks

 

[Lonewulph]

I sent an email to my 3DR support contact asking how to evaluate the WiFI environment to know when it's safe to fly.

Rich did you find any decent 'wifi environment reporting' type of app anywhere for apple and android?

I think I might get on the third party antenna wagon with everyone else.

Thanks

 

[nacjr]

Rich did you find any decent 'wifi environment reporting' type of app anywhere for apple and android?

I think I might get on the third party antenna wagon with everyone else.

Thanks

I use WiFiAnalyzer on my Samsung Tab S 8.4 and seem to work good.

https://goo.gl/kUlxyd

 

[Lonewulph]

K, I'll see if they have that in ios

 

[Rich]

I use 'WiFi Analyzer by farproc' (the same one that @nacjr linked), but I don't know if he has an IOS version.

It's pretty nice and has some nice details and graphs available for surveying the WiFi landscape. Attached is a spot that I was flying and didn't see any issues out to 100M distance and 40M altitude.

Of course, this screen shot was from the ground next to the controller, the Solo itself will see a very different and varying signal environment.

 

[Lonewulph]

Yes I see the Android app in google store, but nothing like it for ios. My eyes are bleeding from sitting here going over all the apps there, nothing looks too exciting so far.

 

[Rich]

I hate to say it, but you can get this from WalMart for $78 and it works great with the Solo except it won't work with Follow Me mode as it doesn't have an internal GPS:
http://www.walmart.com/ip/Nextbook-Ares-8-Tablet-16GB-Quad-Core/43267399

Then you can run all the nice Android apps! :>

 

[NYG]

I posted this on the Facebook Mod group today:

I swapped out the WiFi card in my Solo today. I replaced the stock card with an 800mw MikroTik R11e-2HnD. I'm sure that I'll need to do some tweeking from the command line to get the most from it, and I haven't replaced the card in the controller yet. After the install the controller recognized the Solo as a new Solo and had me pair it by holding down the A+B buttons.

I did some minor testing at local school that's nearby that I frequent for flying. A couple of observations from my testing in this fairly RF noisy area:

With the stock antennas I was getting 600'-700' before the connection would drop and RTH would be initiated. Today with the new card I went 1500' before RTH.

With a pair of router antennas I was going out about 1300'-1500' before RTH. Today I went out 2300'.

I also have a high gain panel setup that I've been using. With the stock Wifi card I was getting just under 3000'. Today I only got out about 2300'. Not sure if it was my aiming or what but I was struggling to keep a good RSSI and kept dropping connection.

My connection would normally drop around an RSSI of -72db. I was able to maintain connection longer with a weaker signal using the new card.

When I did drop connection it appeared to take much longer to re-establish connection with Solo using the new card.

This is all early on and I definitely have more testing and tweaking to do to see if it's all worth while. But the good news is that we have options now and we know other Atheros based cards will work.



Next I'm going to test 1W MIMO booster I have on the controller, then I'm going to replace the stock wifi card in the controller with a MikroTik card of the same model.

 

[Rich]

I posted this on the Facebook Mod group today:

I swapped out the WiFi card in my Solo today. I replaced the stock card with an 800mw MikroTik R11e-2HnD. I'm sure that I'll need to do some tweeking from the command line to get the most from it, and I haven't replaced the card in the controller yet. After the install the controller recognized the Solo as a new Solo and had me pair it by holding down the A+B buttons.

I did some minor testing at local school that's nearby that I frequent for flying. A couple of observations from my testing in this fairly RF noisy area:

With the stock antennas I was getting 600'-700' before the connection would drop and RTH would be initiated. Today with the new card I went 1500' before RTH.

With a pair of router antennas I was going out about 1300'-1500' before RTH. Today I went out 2300'.

I also have a high gain panel setup that I've been using. With the stock Wifi card I was getting just under 3000'. Today I only got out about 2300'. Not sure if it was my aiming or what but I was struggling to keep a good RSSI and kept dropping connection.

My connection would normally drop around an RSSI of -72db. I was able to maintain connection longer with a weaker signal using the new card.

When I did drop connection it appeared to take much longer to re-establish connection with Solo using the new card.

This is all early on and I definitely have more testing and tweaking to do to see if it's all worth while. But the good news is that we have options now and we know other Atheros based cards will work.



Next I'm going to test 1W MIMO booster I have on the controller, then I'm going to replace the stock wifi card in the controller with a MikroTik card of the same model.

Interesting hacking/modding already!

Was this a plug in module? Did it directly plug into the Solo?

I haven't taken the Solo that far apart yet. I wonder how the power consumption changes with the higher powered card?

What was the original card in the Solo? Was it the same brand?

 

[rrmccabe]

For what its worth there are also hacks out there where you can change the country code to increase the power level on current WiFi module. The question at this point is if it works on both 2.4 and 5.8 or just 5.8.

Taiwan allows higher power than US.

 

[Rich]

For what its worth there are also hacks out there where you can change the country code to increase the power level on current WiFi module. The question at this point is if it works on both 2.4 and 5.8 or just 5.8.

Taiwan allows higher power than US.

Possibly... but you need a significant change in power level to make a real difference in range.

For example doubling the output power is only a 3 dB change in power, but it won't make that much of a difference in range. Take a look at your controller and notice the RSSI... 3 dB is like nothing!

But I know that everyone wants as much as they can get, and sometimes every little bit helps, but to get a noticeable difference, you will need to make like a 10dB change... this is a lot more power output... like going from 100 mW to 1000 mW. My guess is that changing the country code won't make this much of a difference, but I could be wrong.

 

[rrmccabe]

Yes I agree. Just like my amateur radio equipment at home. You can never make up for a good performing antenna with a power amplifier.

However I would be thrilled to pick up 3DB. Just not going to do it with this hack they are talking about !

 

[Seabee]

Lonewulph
I believe the real issue in both GPS and controller/Solo com link problems is received signal strength. The GPS signal is very weak because it is being sent by satellites that are 12000
( MEO constellation)and 24000 (WAAS)miles above the earth. Therefore any type of EMI can adversely impact the signal. Note the location of the GPS antenna on the Iris, X8, Blade 350QX2&3 and Chroma.
The Solo appears to use the MIMO modulation technique to improve reception and resist interference(note 2 antennas on the controller and Solo unit). I am not up to speed on this technique. However, if the received signal is low due to low transmitter EIRP, the link is going to be susceptible to all types of EMI/RFI.
The U.S. Cell frequencies should not directly interfere with the 2.4gHz com link signal. However the cell signal strength close to a tower is quite strong and could overload both the com link receiver and the GPS receiver. Would not be a good idea to orbit a cell tower. Also, most/ many tall tower like structures in the U.S. are loaded with cell antennas.
I am certainly not up to speed on the latest hardware and software for radio communication but the Maxwell equations for radio waves and digital modulation techniques from the 1930's are still are valid.

 

[Seabee]

Yes I agree. Just like my amateur radio equipment at home. You can never make up for a good performing antenna with a power amplifier.

However I would be thrilled to pick up 3DB. Just not going to do it with this hack they are talking about !

rrmccabe,

 

[Seabee]

mmccabe,
Please check my math.
If the Solo/controller have a transmit power of 10 mW or 10 dBm( as I have heard) and the rubber duck antenna has a gain of 2 dBi we get an EIRP of 12 dBm.
I think the U.S. 2.4 gHz ISM EIRP limit is 36 dBm, EU limit of 20 dBm.
That gives an actual to limit difference of 24dB which would have a significant impact on range and interference susceptibility.
Thoughts?

73

 

[NYG]

Interesting hacking/modding already!

Was this a plug in module? Did it directly plug into the Solo?

I haven't taken the Solo that far apart yet. I wonder how the power consumption changes with the higher powered card?

What was the original card in the Solo? Was it the same brand?

The wifi cards are mini PCIe. The stock card is based on the Atheros AR9382 chip and the new cards that I'm using are based on the Atheros AR9582. The Solo is using the ath9k driver which appears to support a wide range of Atheros chip sets. I did notice code in the Solo looks like it may limit the card to 500mw output (or 27dbm), but I'm not positive on that. I should be able to override that from the command line if that's the case. In time i'll know after i do more tinkering.

 

[Sarah B]

You can't imagine how fascinating this is to someone who knows nothing about it.

That is all.