Lightbirdge amplifiers

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Hello all

I bought a lightbridge for my naza drone a couple of months ago. Because of poor range, I installed two hobbyking 2W amps on ground unit : things got worse, video got pixellated even at close range.
The best configuration I found is to have one amp on air unit : gives about 1.5 kms of "good quality" range.

However, 1.5 kms still is a bit weak. Therefore I'm looking for some better quality boosters, here are some units I found interresting.

- sunhans 3W
REXUAV | HOME

- rex uav 4W
REXUAV | HOME Appearently not a great choice according to this thread
Sunhans 3W vs FPVLR 4W

- cheap 4W booster
Alibaba Manufacturer Directory - Suppliers, Manufacturers, Exporters & Importers 
couldn't find anything about it

Something else ? Here is an interresting rcgroups thread:
dji lightbridge modifications TX-power/RX sensitivety - RC Groups
According to this guy, it doesn't make sense to install boosters on lightbridge ground unit, it appears however to be fine to install amplifiers on air unit. This would be consistent with my previous results.
I tried to find a booster designed for mimo systems; I found something from sunhans :
SUNHANS - 2.4GHz WiFi MIMO Booster, 1000mW, 300Mbps
Unfortunately it appears to be only two regular boosters packed up in a single box : not interesting.
I've also seen some "dual band booster" :
REXUAV | HOME
not sure what this is about.
I don't plan to improve antennas now ( will do it once I get decent omni range).

I see that a lot of people mess with boosters on their phantom and inspire units, therefore I guess it should be possible to get a decent setup.
If any of you guys has some advice, I'd be happy to read it.
Thanks
 
While not familiar with all the equipment you list... What is your experience with radio equipment?

Cabling, antenna theory, etc.
Not saying you need an Eng. Degree as none of us were born with RF knowledge but unless you have experience it could be other than your equipment.

Not clear from your post but do you understand your problem(s)?
 
It's likely you have things in the wrong order. Your pursuit iof distance should start with high gain antennas (increased directivity) with the boosters as a complimentary upgrade. The reasoning is simple, TX/RX gain on an OMNi will amplify everything received from all sources with a high likelihood of other 802 wifi devices joining in the sharing of channel and bandwidth allocation- for practical purposes think of it as the difference between flying in a neighbourhood or out in a field.
 
Boosting the signal works very well. I use several types of amplifiers and antenna models. Increasing the output DB levels will increase not only range but signal saturation of surroundings making flying with a constant video feed more stable. Amplifying the drone side has the same benefits, however powering the boosters on the drone require added weight of not only the amps themselves but also the needed batteries. I had considered testing this out and may make a video showing the signal level increase of boosting the drones transmitter. I've already made a few videos showing the increased levels using a RF tester giving visual results that are clearly seen to be higher performance. I'm not into great distances, I'm more into greater penetration and saturation of the signal, specifically the video feed.
 
I have the Alibaba ones, I got them from Amazon. They work excellent.
So wait, that lightbridge system for the Naza is pretty expensive. You spent all that money on it and still get poor range? You could have bought a P4 with that money and had almost four miles range out if the box. Not to mention all the other benifits of the P4.
I only use the amplifiers on the remote. One for each antenna. I can fly as far as the battery will take it with zero signal loss.
 
I've been using a UHF control link and 2.4 ghz analog video link coupled with cp antennas for the past two years. The range was nice, about 5 kms with omnidirectional antennas. However, I wanted an HD video feed, and got a lightbridge for about 700 $ ( sure it's expensive for what it is).

So appearently amplifiers on the remote should work well. Interesstingly enough, I got pretty poor results with these :
2.4GHz 2 Watt Signal Amplifier for DJI Phantom 1 & 2 (White)

Maybe they're not the best amplifiers out there, I will something else
I've seen that when the original source is too weak, the amplifier can't boost it efficiently. What about intalling two amplifiers on the same antenna port ? One amp on top of the other ? :D
 
I've been using a UHF control link and 2.4 ghz analog video link coupled with cp antennas for the past two years. The range was nice, about 5 kms with omnidirectional antennas. However, I wanted an HD video feed, and got a lightbridge for about 700 $ ( sure it's expensive for what it is).

So appearently amplifiers on the remote should work well. Interesstingly enough, I got pretty poor results with these :
2.4GHz 2 Watt Signal Amplifier for DJI Phantom 1 & 2 (White)

Maybe they're not the best amplifiers out there, I will something else
I've seen that when the original source is too weak, the amplifier can't boost it efficiently. What about intalling two amplifiers on the same antenna port ? One amp on top of the other ? :D
What about a panel antenna pointes at the AC. Will work better unboosted than fiddling around with extra amps.
 
What about a panel antenna pointes at the AC. Will work better unboosted than fiddling around with extra amps.
A pannel antenna like the DBS one ? I've considered getting one, it's quite bulky though. And I still have the helical antenna I was using with my analogue system ( would need to buy a another one).

But I'm not sure I understood your explanation of why it's a bad idea to use amplifiers : "TX/RX gain on an OMNi will amplify everything received from all sources with a high likelihood of other 802 wifi devices joining in the sharing of channel and bandwidth allocation ".
I thought that the wifi booster only makes the emmitted signal stronger. Does it also amplify signals that are coming in ?
 
Most people don't perform any burdside mods (I understand you are) so a TX only amp is a minor improvement at best. Of course it will be if some use as it will increase the SNR for the contriol signal at the AC in wifi and other signal congested where other services are operating close to where the AC is flying.

The Amps you have linked to above all have RX gain also, they all amplify the received signal.

The beauty of panels or any other form of high gain directional antenna is that they not only increase the strength of the transmitted and received signal within the coverage angle they reject sources outside it, or to put it another way they have less gain than an Omni outside the coverage angle.

Your lightbridge application has a distinct and important difference to your previous analog link. Lightbridge is a fancy name for what is an implementation of the wifbroadcast protocol, it is part of the wifi standards. As in addition to reduced SNR reduction that will present if other devices are in range the lightbridge station will play nicely with other wifi devices detected to allocate channels and share bandwidth. An Omni antenna with an RX amp will may allow other devices to be recognised (that wouldn't be in the absence of the RX amplifier section in the booster) and will, as a consequence, interact with them in an effort to minimise disruption to their devices, this effects the speed and link quality to the AC.
 
I've been using a UHF control link and 2.4 ghz analog video link coupled with cp antennas for the past two years. The range was nice, about 5 kms with omnidirectional antennas. However, I wanted an HD video feed, and got a lightbridge for about 700 $ ( sure it's expensive for what it is).

So appearently amplifiers on the remote should work well. Interesstingly enough, I got pretty poor results with these :
2.4GHz 2 Watt Signal Amplifier for DJI Phantom 1 & 2 (White)

Maybe they're not the best amplifiers out there, I will something else
I've seen that when the original source is too weak, the amplifier can't boost it efficiently. What about intalling two amplifiers on the same antenna port ? One amp on top of the other ? :D
Pre-amping does work. However, the final amps input must not exceed its max rating. Here is a video I did on running two amps:

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The real center of importance though is the RX factor. Control signal boosting isn't really needed for most flights. The video feed is the most important aspect for me. A good amplifier like RF-links has a 20db RX gain. Sunhaus types are around 11-13 db gain.
 
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Most people don't perform any burdside mods (I understand you are) so a TX only amp is a minor improvement at best. Of course it will be if some use as it will increase the SNR for the contriol signal at the AC in wifi and other signal congested where other services are operating close to where the AC is flying.

The Amps you have linked to above all have RX gain also, they all amplify the received signal.

The beauty of panels or any other form of high gain directional antenna is that they not only increase the strength of the transmitted and received signal within the coverage angle they reject sources outside it, or to put it another way they have less gain than an Omni outside the coverage angle.

Your lightbridge application has a distinct and important difference to your previous analog link. Lightbridge is a fancy name for what is an implementation of the wifbroadcast protocol, it is part of the wifi standards. As in addition to reduced SNR reduction that will present if other devices are in range the lightbridge station will play nicely with other wifi devices detected to allocate channels and share bandwidth. An Omni antenna with an RX amp will may allow other devices to be recognised (that wouldn't be in the absence of the RX amplifier section in the booster) and will, as a consequence, interact with them in an effort to minimise disruption to their devices, this effects the speed and link quality to the AC.

Ok so I won't be buying new amps for now as - appearently - the problems come from the fact that I have a lot of wifi around me.
What about some circularly polarised antennas ? Two helicals on the remote and two omni antennas on the drone.
If I'm not mistaken they could help reject noise since the wifi around here is linerarly polarised ...
Since I allready have one omni cp antenna and one 12dB helical antenna, it wouldn't be more expensive than buying a DBSmods pannel antenna.


The real center of importance though is the RX factor. Control signal boosting isn't really needed for most flights. The video feed is the most important aspect for me. A good amplifier like RF-links has a 20db RX gain. Sunhaus types are around 11-13 db gain.
You're talking about this one for example ? LTC Series Tunable WiFi Amplifiers: RF Linx: Wireless LAN Amplifiers, Antennas, and Accessories: RF Linx
It looks like a solid piece of equipment, a bit expensive though :D. Aren't those 20dB excessively amplifying the surrounding noise ?
 
I've been using a UHF control link and 2.4 ghz analog video link coupled with cp antennas for the past two years. The range was nice, about 5 kms with omnidirectional antennas. However, I wanted an HD video feed, and got a lightbridge for about 700 $ ( sure it's expensive for what it is).

So appearently amplifiers on the remote should work well. Interesstingly enough, I got pretty poor results with these :
2.4GHz 2 Watt Signal Amplifier for DJI Phantom 1 & 2 (White)

Maybe they're not the best amplifiers out there, I will something else
I've seen that when the original source is too weak, the amplifier can't boost it efficiently. What about intalling two amplifiers on the same antenna port ? One amp on top of the other ? :D
Yeah, those amplifiers are not good at all. I have read that there is a lot of noise coming out of them.
 
A pannel antenna like the DBS one ? I've considered getting one, it's quite bulky though. And I still have the helical antenna I was using with my analogue system ( would need to buy a another one).

But I'm not sure I understood your explanation of why it's a bad idea to use amplifiers : "TX/RX gain on an OMNi will amplify everything received from all sources with a high likelihood of other 802 wifi devices joining in the sharing of channel and bandwidth allocation ".
I thought that the wifi booster only makes the emmitted signal stronger. Does it also amplify signals that are coming in ?
The wifi amplifiers will amplify the signal in and out of the RC.
 
Probably repeating what was above, got a little confused. The only thing you can do on the drone that will help is a TX amp only and there you're talking weight and battery. You're stuck with an omni on the bird which has a gain of around 2,3db at most. The video on the drone is transmitting only so you don't need a bi-amp unless you're trying to beef up the control signal. The remote control will benefit most from a directional antenna but you have to keep it pointed because it is much worse than an omni off axis. The directional will both reduce the noise it can see as well as increase both the receive and transmit signals. Antenna gain is always preferred over radio gain when possible. The parabolic reflectors and panel antennas all have better gain than the omni but not sure how much, will be testing shortly (I have a spectrum analyzer at work). We use ITElites in our network as well, cheap but a panel antenna is probably the only thing that's practical in this application. Never believe an antenna manufacturer's gain claims, you'll have to go by testing by people in the field. If I'm reading the specs I have seen you're not going to exceed the FCC limits with anything you can practically use for an antenna short of a dish on a tripod with someone to point it.
 
So I bought an additional 2.4 ghz circular wireless helical and one 3w sunhans amp.

New setup
Remote : two circular wireless helical antennas ( 11Dbi according to manufacturer).
Quadcopter : two circularly polarised omnis + one sunhans 3W amp.

I did a quick test flight over the woods yesterday : at a distance of 3.1 km, video signal was 55/100 and control signal ~85/100. Note that there was strong wifi noise around me.

What do you think ? I guess it's not bad (compared to the results I got previously at least).
 

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