Basic Guide to Solo Antennas (Stock, Alfa, FPVLR)

[Pedals2Paddles]

The reason I asked about the Alphas is because I've heard people comment on the FPVLRs being able to penetrate some objects somewhat (without a booster).

Like I said, the edges of trees. Expect nothing more.

 

[spartaHawk]

SOLO V.2 Long Range Kit 10.5dBi - FPVLR

Last question, FPVLR V.2 antennas here say their beam width is 60 degrees (measured at -3dB). I know your OP images aren't meant to be completely accurate, but isn't 60 degrees a fairly wide angle, and it is much wider than that shown in your image? Is the angle you're showing more in the way of realistically dependable signal within such an angle? Or is the dependable angle really a (very wide) 60 degrees now?

 

[Pedals2Paddles]

The images are definitely not drawn with any angular specification. In my experience, 60 degrees is probably pushing it. More like 40-50.

 

[Craig L. Johnson - USMC]

I love this post. thanks for the information.

 

[FinniKris]

Are there any aftermarket omni antennas that will work with the Solo controller & outperform the stock antennas?
How about these?

I use those tplink antenna. It's an upgrade from stock. But that being said only about 20/30% better than stock. I'm saving up for fpvlr.

 

[Michael Lione]

A tremendous amount of excellent information in this thread. Thanks P2P for getting the ball rolling. Your pattern photos are great. I'm retired now but back in the early days of 802.11 I set up several Point to Point data links. Several in this discussion mentioned WiFi contention (congestion). This was, and I assume still is, a factor setting up wifi networks. Besides taking advantage of configuring adjacent APs on different channels we used patch (Alphas) and the even more directional yagi antennas because by their directional polarization they would reject unwanted RF signals that the omni (ducks) picked up. Here's a question I have posed on other threads with no response: Will utilization of directional (linear/circular) antennas besides the obvious increased dbi adding range also assist to reject rouge WiFi contention where it exists to maintain a better Sololink?

 

[Dogman1973]

Will utilization of directional (linear/circular) antennas besides the obvious increased dbi adding range also assist to reject rouge WiFi contention where it exists to maintain a better Sololink?

In theory yes, rejecting spurious noise outside of the antenna beamwidth can make a significant difference... but the reality for a drone is that adding directional antennas at the controller does nothing for the received noise floor at the bird.
Receiver noise (ie other wifi, microwaves, cordless phones etc) is far less of a problem for the controller, purely because you're standing at ground level... you'll have limited exposure to that noise because of your surroundings.
The bird on the other hand, even at modest altitude, will be receiving noise over a much bigger area.

Over built up areas, you'd be looking at a noise floor asymmetry of well over 10dB... in sparser areas it may only be a few dB, and of course in remote areas theres unlikely to be any difference.
Sadly the Solo doesnt report the SNR (Signal to Noise Ratio), which is a far better indication of signal quality than RSSI alone (much like HDOP is to number of satellites for GPS)

Short version, high gain antennas on the controller will be far more effective in remote areas than they are in builtup/suburban.

 

[Michael Lione]

Thanks Dogman 1973. Your information is well received and very much appreciated. I assumed almost the opposite, that the bird was protected from rouge RF by it's altitude. You explanation goes far to explain why there can be a sudden drop off and even loss of the sololink as it continues along a flight path.

 

[Dogman1973]

I forgot to add... it's worth having a simple wifi scanning tool on you phone tablet (eg WifiAnalyser) which will give you an idea of how much wifi is around (at ground level at least).
First thing I do before I fly is check that, which gives me a confidence factor on what my likely max range might be

 

[Michael Lione]

Back at you Dogman 1973. That is indeed excellent advice. I use several apps to test the environment that I launch from besides the popular weather and flight restriction information. I had a chance to get in some flying in a couple of days ago. It was cold, overcast, but calm so I used the time to practice my manual flying and conduct some very unscientific testing. I fly in a small very rural town park in NE Pennsylvania.

I fly two Solos both with RevA/V2 GPS. I locked 13 SATs with a HDOP .8 in about three minutes.

I use several site scan apps which reported these values on the day I was out.
GPS- 11 locks out of 22 available with .8 HDOP which coincided with my actual GPS locks.
EMF- 44-55 ut
WiFi contention- two sources @ -89 dB

Antenna testing-
I flew three flights all to the same point; 400'AGL at 150' out.
1st flight with stock ducks rendered a -75 dB.
2nd flight with Alphas got -61 dB.
3rd flight with Duck/Alpha combo got -57 dB.

As a side note I could effect my signal strength pretty dramatically (+/- 10dB) by purposely pointing the dual patch (linear) configuration away from the Solo which gives credence to the warnings that flying directly over head your ground control location with directional antennas can find the bird in the donut with a low signal. As you would expect there was little or no effect at this short distance with either of the other two configurations.

One thing I have asked in past discussions that got no response is if there is any thumb or rule as to a RSSI value that signals a RTH. You mention SNR and I can easily see that to be a much better parameter to predict the reliability of the sololink. Do you know which end of the link the displayed RSSI is measured?

 

[Dogman1973]

I believe the RSSI reported is that of the receiver on the bird (someone else may be able to confirm)

A rule of thumb is difficult to establish, because of the wonders of MIMO, a slight change of aspect can yield wildly different results.(as you noted above).

For example, I live in Melbourne Australia... have done a significant amount of 2.4GHz survey over the years... on tall buildings and small mountains/hills around the city and inner suburbs... the noise floor is sometimes well into the -80dB range... my assumption is the minimum SNR to support sololink would surely be atleast 10dB meaning below -70dB could start getting dicey.

In contrast out in rural areas it'd be below -100dB, and given the rx sensitivity of the cards is probably in the mid -90's you're safe out there with RSSI right down into the -90's

On the SNR thing... I'm sure the atheros drivers would be able to report it... but i dont think the solo api exposes it. Maybe a python script executed by solex could be a crude way to get it... will look into that.

 

[Michael Lione]

I believe the RSSI reported is that of the receiver on the bird (someone else may be able to confirm)

A rule of thumb is difficult to establish, because of the wonders of MIMO, a slight change of aspect can yield wildly different results.(as you noted above).

For example, I live in Melbourne Australia... have done a significant amount of 2.4GHz survey over the years... on tall buildings and small mountains/hills around the city and inner suburbs... the noise floor is sometimes well into the -80dB range... my assumption is the minimum SNR to support sololink would surely be atleast 10dB meaning below -70dB could start getting dicey.

In contrast out in rural areas it'd be below -100dB, and given the rx sensitivity of the cards is probably in the mid -90's you're safe out there with RSSI right down into the -90's

On the SNR thing... I'm sure the atheros drivers would be able to report it... but i dont think the solo api exposes it. Maybe a python script executed by solex could be a crude way to get it... will look into that.

Again my sincere thanks for taking the time to provide all of this information and valuable insight.

 

[3drHighMileFlyer]

I'm hoping this post can be stickied to the top. Lots of newbs, and apparently everyone wants to know about antenna options. So rather than answering the same question 57 times per week, perhaps this will be a good place for those answers to be found. I put together these infographics to explain the difference between the stock antennas, the popular alfa paddles, and the popular FPVLR type system. Some of images in these graphics are my own. Some of them I stole from the internet. Sue me later. Some of my spelling may be wrong too. I generally don't care

Very interesting, I was getting roughly up to 1,000 feet with the dji reflector attachments and less with only the stock antennas only. Today I pushed right up to 1,800 feet with stock and attachment on as well. Rth activated just like normal and came back and I regained signal at 800 feet away. I ordered the Alfa pad antennas and will be getting them in the mail Wednesday. I'm holding they increase my range where I have at least 3 solid bars at 1,800 feet or about. I'm not looking for 3,000 plus feet. Just a solid connection about 1,500- 2,400 feet.

 

[jimw1956]

Not recommended. They will waste half their energy blasting into the ground under your feet. A higher gain omni antenna is really only useful if it is mounted vertically on a mast or rooftop. Attached to the controller, they're not able to work properly.

Thank you, I had also wondered about higher gain omnis.

 

[mikeo]

This seems like the best place to post this, and I'm not trying to play the "my junk is bigger than your junk" game, but I got over 10,000 ft with the Alfa antennas today. I had to turn around since I had a tailwind (2-3 MPH) outbound and was over water. I wanted to make sure I could land safely. Since "this thread is worthless without pictures" and "pics or it didn't happen" here is my screenshot:

If you're on the fence about spending $20 on the Alfa antennas or trying to save for FPVLR, I'd take the Alfa antennas as the best value any day! Here's the exact link:
https://smile.amazon.com/gp/product/B003ZWPS3O

edit: I wanted to also state that I did NOT have any type of amplifier or WiFi card mod in use/installed. This is a stock Solo controller with the Alfa antennas attached.

 

[3drHighMileFlyer]

This seems like the best place to post this, and I'm not trying to play the "my junk is bigger than your junk" game, but I got over 10,000 ft with the Alfa antennas today. I had to turn around since I had a tailwind (2-3 MPH) outbound and was over water. I wanted to make sure I could land safely. Since "this thread is worthless without pictures" and "pics or it didn't happen" here is my screenshot:
View attachment 5162
If you're on the fence about spending $20 on the Alfa antennas or trying to save for FPVLR, I'd take the Alfa antennas as the best value any day! Here's the exact link:
https://smile.amazon.com/gp/product/B003ZWPS3O

edit: I wanted to also state that I did NOT have any type of amplifier or WiFi card mod in use/installed. This is a stock Solo controller with the Alfa antennas attached.

Very interesting your experience with the Alfa antennas. I had similar positive out comes from them as well. On stock around my neighborhood I could only reach 900 ft in one direction and got roughly 1,800 feet in another direction over the rail road tracks. Dji reflectors didn't help at all over the 900 ft direction but helped with the rail road track test direction. At work I was able to hit 1,900 feet on direction and two days ago I pulled 2,400 feet in another direction with stock and just the reflectors attached. I received my Alfa pair from amazon yesterday and just tested them 30 minutes ago at work. I was able to hit past the 2,000 mark where rth would start with still 3 bars on the screen where before it would be 1,900 feet with spotty one bar. The direction that I hit 2,400 feet with stock and reflectors I only had one spotty bar and barely could control the drone but today with the Alfa swap I went past to the 3,000 mark with still 2 bar solid and a nice video connection. I turned around because I couldn't see the drone and I was getting a little nervous.
Overall I think these Alfa antennas are the way to go if your looking for a solid connection 1,000 to 2,700 feet away. Anything thing past that is just teasing your luck and what not.

 

[3drHighMileFlyer]

Very interesting your experience with the Alfa antennas. I had similar positive out comes from them as well. On stock around my neighborhood I could only reach 900 ft in one direction and got roughly 1,800 feet in another direction over the rail road tracks. Dji reflectors didn't help at all over the 900 ft direction but helped with the rail road track test direction. At work I was able to hit 1,900 feet on direction and two days ago I pulled 2,400 feet in another direction with stock and just the reflectors attached. I received my Alfa pair from amazon yesterday and just tested them 30 minutes ago at work. I was able to hit past the 2,000 mark where rth would start with still 3 bars on the screen where before it would be 1,900 feet with spotty one bar. The direction that I hit 2,400 feet with stock and reflectors I only had one spotty bar and barely could control the drone but today with the Alfa swap I went past to the 3,000 mark with still 2 bar solid and a nice video connection. I turned around because I couldn't see the drone and I was getting a little nervous.
Overall I think these Alfa antennas are the way to go if your looking for a solid connection 1,000 to 2,700 feet away. Anything thing past that is just teasing your luck and what not.

I am happy with the outcome and won't proceed with the wifi card upgrade or different antennas. 2,500 feet with a great solid connection is all I wanted out of the box. Now I am happier with my drone.

 

[dmyhill]

Overall I think these Alfa antennas are the way to go if your looking for a solid connection 1,000 to 2,700 feet away. Anything thing past that is just teasing your luck and what not.

You might also be testing the limits of what can be termed Visual Line of Sight.

 

[dmyhill]

I do not see a discussion here of parabolic reflectors (such as those so popular with DJI products). Are they not applicable to the type of system on Solo?

 

[3drHighMileFlyer]

You might also be testing the limits of what can be termed Visual Line of Sight.

I agree, past 2,300 feet or so I can't see the drone if there's trees or building near me. I agree definitely fly in your line of site.
I was running into problems where I would loose connection roughly 900ft to 1,400 depending on the day. All i wanted was a solid connection past 900ft and up to 2,500 feet depending where I fly and can have a visual line of sight at all times. Less then 900 feet when the drone returns to home is way to short with stock antennas and a few barrieiers such as tress and other wifi interference