Anyone try this Circular Polarized Antenna from RexUAV?

[CyberNate]

I just bought this on Amazon:

Amazon.com: 2017 REXUAV - DJI, 3DR Solo 2.4GHz CP Long Range Antenna V4: Computers & Accessories

It's made out of pure silver and has true 9.5db gain. The RX and TX are polarized in opposite directions which will make for good separation, perfect for amplifying both sides. There is no mount for the Mavic. I think I'll make one out of some old tablet holder parts. This type of antenna should give better penetration than the panel type and better for amplifying the RX side.

Edit: Apparently I bought the one that is NOT pure silver by mistake. Hmmm, is it worth $50 to upgrade to pure silver?

 

[CyberNate]

A bit ridiculous looking, but works well. The circular polarizing design allows for better amplification of receiving channel. My signal is considerably stronger than the fpvlr with same amplification.

 

[HFMan]

Aren't the Mavic antennas linear (vertical) polarization? If so, you lose 3dB due to polarization mis-match.

 

[CyberNate]

Aren't the Mavic antennas linear (vertical) polarization? If so, you lose 3dB due to polarization mis-match.

Yes, that's true. It's not an ideal antenna for the Mavic. I had cancelled the order, but they sent it anyway. I decided to try it out. It still manages to outperform the FPVLR surprisingly. I have no plans to change the drone antenna to add circular polarizing. Not worth the hassle.

 

[WEOTN]

Here's a nice write-up on circular polarized antenna, and benefits etc...
Circular polarization explained – RCExplorer

 

[CyberNate]

Aren't the Mavic antennas linear (vertical) polarization? If so, you lose 3dB due to polarization mis-match.

I read the articles that talk about linear to Circular Polarized loss, but even with that I'm seeing WAY better signal with this CP antenna. I flew through trees, hills, buildings and dense clouds up the side of a steep foothill. With my stock I can only get around a 5000 to 8000 and that's flying way higher than I should . With the FPVLR boosted, I got 14,518 feet before complete signal loss.



With the RexUAV CP antenna I never reached the end of the signal. I had to abort at 18,200ft because I was in the clouds and would run into the side of the mountain/foothill. I still had signal:



Shot as I head into cloud:



Forced to turn around due to no visibility:



Nice view after turning around:


Now if I only had a DBMOD Elite antenna to test...

 

[WEOTN]

Great post CyberNate, thanks for sharing!

A couple bits of info that may help here. Most man-made RF signal and noise is vertically polarized, so most interference is too. It's advantage is it radiates out like ripples in a pond in all directions equally. There's almost nothing CP in nature, and very little in man made RF in comparison.

CyberNate's success is likely a combination of the added gain through directionality of the CP antenna, lack of noise interference on the operators end, so even with 3db loss, it's probably offset by 8db gain from the antenna (have not looked for specs but guestimating from signal increases noted above), so there's a net gain of 5db. Guestimates.

The Mavic at elevation is away from most signal and noise so has less struggle to receive the CP signal through RF clutter even though polarization differences exist. It would be interesting to test having CP antennae on the Mavic itself like in the article. Probably no way to test it without voiding warranty, so it may be a while before I try it.

Oh, I'm a HAM radio operator of 30+ years and have dabbled in HF through microwave comms. It's fun stuff if you're into it.

Has anyone decompiled the DJI code? Would be fun if there were open source firmware to play with.

 

[CyberNate]

Great post CyberNate, thanks for sharing!

A couple bits of info that may help here. Most man-made RF signal and noise is vertically polarized, so most interference is too. It's advantage is it radiates out like ripples in a pond in all directions equally. There's almost nothing CP in nature, and very little in man made RF in comparison.

CyberNate's success is likely a combination of the added gain through directionality of the CP antenna, lack of noise interference on the operators end, so even with 3db loss, it's probably offset by 8db gain from the antenna (have not looked for specs but guestimating from signal increases noted above), so there's a net gain of 5db. Guestimates.

The Mavic at elevation is away from most signal and noise so has less struggle to receive the CP signal through RF clutter even though polarization differences exist. It would be interesting to test having CP antennae on the Mavic itself like in the article. Probably no way to test it without voiding warranty, so it may be a while before I try it.

Oh, I'm a HAM radio operator of 30+ years and have dabbled in HF through microwave comms. It's fun stuff if you're into it.

Has anyone decompiled the DJI code? Would be fun if there were open source firmware to play with.

I'm from Minnesota as well. Just noticed that on your profile. I plan to take my Mavic back to Minnesota this summer around the Twin Cities area.

 

[CyberNate]

Great post CyberNate, thanks for sharing!

A couple bits of info that may help here. Most man-made RF signal and noise is vertically polarized, so most interference is too. It's advantage is it radiates out like ripples in a pond in all directions equally. There's almost nothing CP in nature, and very little in man made RF in comparison.

CyberNate's success is likely a combination of the added gain through directionality of the CP antenna, lack of noise interference on the operators end, so even with 3db loss, it's probably offset by 8db gain from the antenna (have not looked for specs but guestimating from signal increases noted above), so there's a net gain of 5db. Guestimates.

The Mavic at elevation is away from most signal and noise so has less struggle to receive the CP signal through RF clutter even though polarization differences exist. It would be interesting to test having CP antennae on the Mavic itself like in the article. Probably no way to test it without voiding warranty, so it may be a while before I try it.

Oh, I'm a HAM radio operator of 30+ years and have dabbled in HF through microwave comms. It's fun stuff if you're into it.

Has anyone decompiled the DJI code? Would be fun if there were open source firmware to play with.

Please keep in mind that I have amplifiers on the RexUAV CP antennae as well. I have dual 3watt amplifiers, one for TX and other for RX. Nice thing about the CP antennae, I don't get cross-over interference. My amps have a blue led that blinks where there is transmission. With the linear polarized antennae (FPVLR Yagi type) I get cross-over interference as can be seen by the RX side blinking along with the TX. With the CP antennae I don't see that. The RX side stays white as it should. I assume that this helps the signal as I'm not seeing my own TX signal as interference on the RX side. Anyway, I'm pretty happy with these CP antenna. I still want to try a panel antenna as well. I suppose panel type will be best for low interference location if I'm going for max range, while the CP type will be best for place with lots of interference and obstructions like buildings and trees.

Edit: Regarding the RexUAV listed gain, it is listed at "an honest 9.5db". Similar FPVLR are listed at 10.5db. I expect that these are comparable to the FPVLR CP type antenae.

 

[WEOTN]

Wonderful! Great news there's linears for this kit! I'd have to check but my HAM license probably allows me use of linears as well. I'm curious who makes yours. My guestimates weren't too far off for an old fart! With present USFAA restrictions on altitude and range, I may never need them, but what better assurance can one have of control than power plus mitigation of interference on a very noisy band.

If you do make it back this way I'd love to see your rig. I'll have some airtime by then so will know what I’m looking at and can compare. Ever stood atop Palisade Head north of Silver Bay? Likely my first long distance outing. Line of sight can go pretty durn far up there!

This just keeps getting better, and if I get really crazy, there's a P4Advanced or Pro... But then the Inspire does inspire. What's money? Right.

 

[Wombat55]

I just bought this on Amazon:

Amazon.com: 2017 REXUAV - DJI, 3DR Solo 2.4GHz CP Long Range Antenna V4: Computers & Accessories

It's made out of pure silver and has true 9.5db gain. The RX and TX are polarized in opposite directions which will make for good separation, perfect for amplifying both sides. There is no mount for the Mavic. I think I'll make one out of some old tablet holder parts. This type of antenna should give better penetration than the panel type and better for amplifying the RX side.

Edit: Apparently I bought the one that is NOT pure silver by mistake. Hmmm, is it worth $50 to upgrade to pure silver?

Silver? The Amazon listing says copper, not silver. Also, copper is a better electrical conductor than silver, so what makes you think that silver would be better?

 

[CyberNate]

Silver? The Amazon listing says copper, not silver. Also, copper is a better electrical conductor than silver, so what makes you think that silver would be better?

Nothing, that's why I asked if it's worth it. I don't know so much about antennae. I read somewhere that silver is better, but not verified.

 

[TrayBoz]

.... when 4.5 miles isnt QUITE far enough.... [emoji6]

 

[jkantiques]

Nothing, that's why I asked if it's worth it. I don't know so much about antennae. I read somewhere that silver is better, but not verified.

Nothing, that's why I asked if it's worth it. I don't know so much about antennae. I read somewhere that silver is better, but not verified.

Hey CyberNate,
I just bought both CP antennas from his website, the copper and
the silver one,.......the silver is giving me 20% increase from the
copper....the facts listed below..

So if all metals conduct electricity, how do they all rank? Take a look at this chart:

Material IACS (International Annealed Copper Standard)
Ranking Metal % Conductivity*
1 Silver (Pure) 105%
2 Copper 100%
3 Gold (Pure) 70%
4 Aluminum 61%
5 Brass 28%
6 Zinc 27%
7 Nickel 22%
8 Iron (Pure) 17%
9 Tin 15%
10 Phosphor Bronze 15%
11 Steel (Stainless included) 3-15%
12 Lead (Pure) 7%
13 Nickel Aluminum Bronze 7%

 

[CyberNate]

.... when 4.5 miles isnt QUITE far enough.... [emoji6]

Yes, true if you are in a place with no interference and obstructions. I have flown closer to 25,000 out in stock form, but I've also had flights in environments where 3000 ft is all I can get due to interference. I love having a strong signal and the feeling that I can fly whether I want to go without far off losing control.

I also love tinkering and just seeing what works best.

 

[CyberNate]

Good results with this setup today with 32526.1 ft range. Could go further with a better battery setup.

 

[Mavman]

What app is that in the pictures?

 

[Wombat55]

Hey CyberNate,
I just bought both CP antennas from his website, the copper and
the silver one,.......the silver is giving me 20% increase from the
copper....the facts listed below..

So if all metals conduct electricity, how do they all rank? Take a look at this chart:

Material IACS (International Annealed Copper Standard)
Ranking Metal % Conductivity*
1 Silver (Pure) 105%
2 Copper 100%
3 Gold (Pure) 70%
4 Aluminum 61%
5 Brass 28%
6 Zinc 27%
7 Nickel 22%
8 Iron (Pure) 17%
9 Tin 15%
10 Phosphor Bronze 15%
11 Steel (Stainless included) 3-15%
12 Lead (Pure) 7%
13 Nickel Aluminum Bronze 7%

Silver is indeed a slightly better conductor than copper. (I was incorrect when I said earlier that I thought that copper was the best conductor). But the margin by which silver is a better conductor than copper (about 5%) is for most practical purposes nil, especially considering the cost of silver versus copper. The semiconductor industry has moved from aluminum wires to copper wires on their integrated circuits (IC's) due to the higher conductivity of copper versus that of aluminum. But I know of no present or planned effort to go from copper wires to silver wires on IC's. For only a small 5% increase in conductivity, the cost-to-benefit ratio is simply not very favorable.

If one really wanted to significantly decrease the electrical conductivity of the electrical wires in their antenna and time, trouble, and cost were no concern, then the thing to do is not to go from a copper antenna to a silver antenna (which, again, gives only a 5% increase in conductivity), but to come up with a contraption so that one could immerse one's copper antenna in a container of liquid nitrogen (boiling point of liquid nitrogen = 77 Kelvin = - 196 Celsius = - 321 Fahrenheit ) while it is being used. That would increase the electrical conductivity of copper by at least 200% or 300% or even more. Much more than a measly 5% increase in conductivity by just going from a room-temperature copper antenna to a room-temperature silver antenna.

 

[CyberNate]

What app is that in the pictures?

That's just the flight log of DJI Go 4. There you can replay the entire flight from a satellite map top perspective.

 

[flyNfrank]

I have been flying 29,000ft-31,000ft round trip using $16 Parabolic Antenna Enhancer. It takes 3-5 seconds to slip it on and go fly.

Not sure how you can beat that bang for the buck setup. Dynamic 3D Solutions