Quick review: FPVLR Circular Polarised antennas for Phantom 4 Professional

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Why bother with circular polarised antennas? Well - for those who know about radio transceiver systems, it all boils down to three elements: range, signal strength and reliability, and penetration. But there is more also. The linear stock antennas, regardless of whether you have parabolic mirrors on them or similar are still vertically polarised: that means, for best signal strength, your controller needs to be held absolutely parallel with your drone, otherwise, signal strength does rapidly drop off as the degrees of "rotation" increase off that parallel. The solution: circular polarised antennas using helical copper wideband antennas, as featured on the FPVLR set up.

What these do is give - unboosted - an 11dbm power gain over stock, and also provide a directional "bore" giving greater penetrative strength through clutter/ line of sight obstacles too. You can boost these antennas by adding 2.4Ghz amplifiers, which increase that gain to between +17-22dbm. Putting that into perspective, for every -3dbm you lose, the transmit power halves, and dBs read similarly to a logarithmic multiplication like, for example, the Richter Scale for earthquakes. So - you are significantly increasing your signal quality, plus, reducing significantly the risk of signal loss when your controller position is rotated perpendicular to your aircraft.

There is ONE THING though, a disadvantage of sorts: the transmission system of the P4P is dual frequency, switchable, but you cannot get switchable amplifiers between the 2.4G and 5.8G options. You can, however, make a choice: I have placed an order to get 2.4G amps to boost the main frequency, and I can turn off the amps if I want to use 5.8G frequency just through the antennas, which does work: and the 11dBm gain still gives a great secondary option compared to stock, especially as the 5.8 G operating distance is significantly less than 2.4G. the other reason is that 5.8g amps are significantly more expensive to purchase. If you are not bothered interchanging amps on your bracket, you could go for both - though ensure DJI GO is operating at the correct frequency before you attempt to take off.

The build quality is great and so are the parts top quality: you get copper wideband antennas, not cheap steel or aluminium ones, they are well put together in front of rear brass shields behind (to reduce rear lobe leakage), and the connectors and coaxial cables are military grade rating, which is cool. It is not cheap, at around €160 for the unboosted kit, and as you must buy the boosted kit with accessory purchases (as I have ordered), the price will go up to around €280 once you've added amps, coaxial cables and L-ion booster battery pack.

Is it worth it? Oh yes, is it ever - even in unboosted spec. The reason I got it was because the 2.4Ghz band has a lot of competing users on the ground: WiFi being kicked out from people's houses, hotspots, hotels, etc., as simple examples, and these antennas will "Louden" your footprint from the drone to the ground, also reducing the risk of disconnects, which is an immediate benefit I have found. In addition, my 5 bars of TX quality remain almost perpetually within a broad radius, even with trees, foliage or other clutter in line of sight. They also appear more resistant to reflected path over glass like water surfaces, which is a bonus.

Some might ask: "but isn't that overkill when we can only fly within a 500 metre radius?". On the face of it, yes: but, it is a bit like asking a person why they buy a watch water resistant down to 200 metres if they are not going to dive: still gives reassurance if you drop it in the sink! And so the same principle for why I opted for these antennas: I want to maximize the signal strength and quality I get at ALL times, regardless where I am and especially when in tricky locations where line of sight can be compromised. Added to these technical benefits, they are dead easy to install, and they even look good: remeniscent of 1950-60 cult sci fi film laser guns (if that sort of thing matters to you, of course).

I thoroughly recommend these, they are well put together, and you can opt to either / or boost your 2.4G or 5.8G options, or have both options IF you want that (and if you are feeling flush). I would never recommend breaking the law by testing their range outright, but the boosted set up is rated at around 15-25kms depending on the atmospheric conditions you have on the day. That does give peace of mind when operating at shorter legal distances at the very least.

Thank you for reading! Go to www.fpvlr.com: they have custom set ups not only for the P4P but now also for the Mavic, Yuneec drones, the 3DR American drone, the new Spark, and Inspire, as well as others. Worth considering for seriously improving the reliability and capabilities of your drone transmission system
 

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I actually have been recently using the FPVLR set up. So far, its boosted the signal enough where I the Controller had not complained about week signal. For example 2000' vertical by a 500' altitude, the signal from RC to AC remains at full bars. Also, it requires no additional modification to your RC. Snap it in place screw on the antenna leads and you ready to go.
 
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I actually have been recently using the FPVLR set up. So far, its boosted the signal enough where I the Controller had not complained about week signal. For example 2000' vertical by a 500' altitude, the signal from RC to AC remains at full bars. Also, it requires no additional modification to your RC. Snap it in place screw on the antenna leads and you ready to go.
Very true... Just need to replace the internal connecting antenna cables to the holes where the stock antennas used to go and you are laughing. It is the main reason why I have done it: to stop the Tx/Rx signal strength from getting compromised, and it seems to work a treat :)
 
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I fitted a boosted FPVLR setup to my P4 to give me more penetration through the forest where I live. In standard trim, I would run out of puff at 500 mtrs trying to negotiate the canopy, now I have full video and control at 1000 mtrs and in open areas, the AC battery is the only restriction. The cost of the conversion was roughly the cost of updating my controller from the (apparently the weakest P4 DJI controller) to another more powerful controller.
Best mod I've ever done, although I needed an extra carry bag due to having to unbolt and trying to pack the unit in my existing backpack.
 
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I fitted a boosted FPVLR setup to my P4 to give me more penetration through the forest where I live. In standard trim, I would run out of puff at 500 mtrs trying to negotiate the canopy, now I have full video and control at 1000 mtrs and in open areas, the AC battery is the only restriction. The cost of the conversion was roughly the cost of updating my controller from the (apparently the weakest P4 DJI controller) to another more powerful controller.
Best mod I've ever done, although I needed an extra carry bag due to having to unbolt and trying to pack the unit in my existing backpack.
That is very true that these kinds of mods do make the controller bigger and a bit heavier. I think the trade off is worth it though. Plus, if needs be, kits like the FPVLR sets can be detached easily enough, though it means some "wiring up" prep work before you fly. Better transmission system does give far more peace of mind though, in my opinion
 
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That is very true that these kinds of mods do make the controller bigger and a bit heavier. I think the trade off is worth it though. Plus, if needs be, kits like the FPVLR sets can be detached easily enough, though it means some "wiring up" prep work before you fly. Better transmission system does give far more peace of mind though, in my opinion
Agreed, I use a neck strap so the extra bulk is not an issue. As you have noted, the trade off far outweighs any transporting concerns and fixed my control and video signal for good and I can enjoy my flying without suffering the original continuous dropouts and unwanted RTH events.
 
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I bought one of the FPVLR setups for my Yuneec drone. It worked good but the bulk of the setup was a real hassle. I like the Itelite antenna better, and their latest version is good for 2.4 or 5.8ghz. It's fits in my Think Tank backpack. Over 5 mile range with LOS connection, no amps.
 
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Agreed, I use a neck strap so the extra bulk is not an issue. As you have noted, the trade off far outweighs any transporting concerns and fixed my control and video signal for good and I can enjoy my flying without suffering the original continuous dropouts and unwanted RTH events.
Good idea actually mate: so far I have failed to purchase something like a lanyard. are they comfortable?
 
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Good idea actually mate: so far I have failed to purchase something like a lanyard. are they comfortable?
I purchased a quality lanyard (for once) that is about an inch wide and it made the whole experience more secure and comfortable. It also cured my habit of dropping things so I'm now looking for one to suit a beer bottle.
 
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image.jpeg
A beer lanyard, now THERE is an idea :))
Actually I used to have a hat mounted can holder that I took on my trips through Asia and India. I fell into a surging storm water drain and that was the end of that....
You can buy a variety of stubby holders with lanyards over here, so I may have to get one for the cricket season that is about to start.
 
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