Final Word On Range Extenders?

[AZDave]

I think the OP needs to look up what signal-to-noise ratio means and how RF works. S/N is what determines how well the receivers in BOTH the drone and the controller can decode transmissions. For a given signal strength, the background noise determines the signal-to-noise ratio and therefore the reliability of contact. The noise in an urban location at microwave (i.e., WiFi) frequencies is generally far greater than it is out in a quiet environment with flat open terrain where DJI almost certainly did their tests. Not to mention that signal reflections from buildings can cause lots of interference problems irrespective of the noise.

Amplifiers can boost the signal from the controller but generally not from the drone. Proper directional antennas on the controller work for BOTH sides of the transmission, both by boosting gain and also by discriminating against noise coming from a direction other than where it is pointed. They do, however, require making sure that the antenna is always pointed at the drone ... otherwise they will work worse than the stock antennas because they will discriminate against the signal coming from the drone.

 

[AZDave]

Thats true, but it would simply make things worse.

A directional antenna must be pointed precisely at the aircraft to get the peak power to it – which is the whole point of an amplifier - get more power to the target to extend range.

The farther away the target is, the smaller the allowable error in pointing the transmitter.

In any case, the cheap antenna design on the RC2 and N1/2/3 certainly aren't ideal omnidirectional radiators (no antenna is), but they're laughable as directed beam antennas. Without even looking at a power plot, from what I learned in microwave antenna design way back in college, those antennas will have several lobes, and leak tons of signal outside them.

The stock antennas in the controller are actually two antennas fed in phase which results in a broad bidirectional pattern ... forward toward the drone and backward toward the pilot. The theoretical pattern from that kind of two element array has no additional lobes if the spacing is correct, but I'd bet that the antennas are some sort of compromise and I'd bet that there are all kinds of internal reflections and interactions that additionally compromise the pattern.

The yagi addon antennas redirect the backward energy forward, as well as focusing some of the side energy into a narrower pattern. They work.

 

[mavictk]

So this is a 15.38% boost, would that equate to a 15.38% range increase? What about + the Yagi-Uda antennae attached? Could I hope for a 20% range increase with the two things combined?

And how would this compare to just getting the Alientech, since the drone-hacks FCC boost is 40 Euro?

What level of boost would the Alientech give? Could it get me to the point where the battery becomes the limiting factor on range? Would the FCC boost do that anyway?

I apologize, I just don't know the ratios of input to range and so on.

I thought that increased dbm had a non linear affect. I asked Grok, an AI, which could be wrong and got the following answer. Given that I am ignorant in this area I thought this might be informative.

 

[DarR-T]

those little 12 dollar range extenders WORK!! Alientech is nice if you are going long distances all the time. BUT as said unless you have a waiver the 12 dollar ones are the best.

The drone pilot association of Canada is working closely with TC to offer BVLOS.
I ordered one of those gadgets but have yet to fly with it. -25 Celsius here.
Cell phone Dongle 2 would be excellent if it were to be available in North-America.

 

[hank970]

Range extenders: bump-stocks for drones.

 

[tstr14]

Range extenders: bump-stocks for drones.

After you've the real thing, bump stocks are boring.

 

[theory81]

I've been doing a bit of research (both here and elsewhere) for range extension options. I've been pretty dissatisfied on the range with this Mavic 2 Zoom that I bought second hand, and can't seem to get the drone anywhere near its maximum flight range as per DJI official data. Also important to add that I fly in mostly urban environments.

First flight on Dual Band I achieved 1333m (before black screen and return home).

Second flight on 5.8GHz I achieved 1718m (before black screen and return home).

Not sure if either were just flukes, but regardless this is nowhere near 11mi (tested on friends Mavic 2 Pro and it probably went about 700m before black screen and return home).

In my research I've come across three things:

First: The Alientech Duo II as per this post: Upgrade to the ALIENTECH DUO II: Leave Beginner Mode Behind.
This seems like a good option, and gets some good feedback, but is pretty expensive and I'd like to weigh some options before dropping on this.

Second: I've found is this thread: What is the BEST range extender right now for Mavic 2 Zoom?
This particular thread discusses three options as far as I can tell:

- Titan drones "command case"
- 4 Hawks "retrofit kit"
- Dual SunHans 5.8GHz signal booster with Raptor XR passive antenna system.

Quite a lot of information here that, as a novice, I'm trying to get straight.

This thread is also 4 years old, so I would guess there would be quite a few updates since then.
I would appreciate any clarity on that stuff if it's still relevant.

Third: I found these little things on Amazon that go for $12.00: Amazon.com

No idea what to think about these. If they gave you 10% more range for $12.00 I would guess that would be worth it for a lot of folks.


Conclusion:

I'd like a solid solution and don't mind spending a bit of money ($400 is probably the top of my range here, but open to anything if it's great). I would be happy if I could even get to 5 out of the 11 miles that DJI describes.

Any information is appreciated and welcomed, thanks.

Para yagi's...in conjunction together easily doubled my mini 2 se range. The key take away is your transmitter must have an unobstructed line of sight with the drone...also interference signals will thrash your range