The 4km club Long Range FPV

[flight-of-eye]

You guys are correct,
with the new antenna I am trying to take advantage of MIMO technology.
In a few words it's not just a diversity solution, but it will allow multiple streams of data, it will combine data streams to increase data throughput. We know streaming video through wi-fi is a bandwidth hog, this will greatly increase our chances of sending those few extra Mb that make the difference.

That is nice, what might be the cost and will we need to upgrade the UAV as well? With what?

 

[flight-of-eye]

Is that directional or omni?

 

[tizzl10]

You guys are correct,
with the new antenna I am trying to take advantage of MIMO technology.
In a few words it's not just a diversity solution, but it will allow multiple streams of data, it will combine data streams to increase data throughput. We know streaming video through wi-fi is a bandwidth hog, this will greatly increase our chances of sending those few extra Mb that make the difference.

this is cool lookin. how does it attach to the transmitter?

 

[themosttoys]

YOu can leave the phantom unmodified for 3000+ ft of range, or upgrade with 2 LHCP pinwheels to get 10000+ ft.

FPVLR - I think you are doing great work and I trust that your antennas are high quality. That said, claiming distance without real world testing (of the Vision wifi) could be misleading. To date, to the best of my knowledge, I am the only one to have FPV at or over 10,000 feet (12,800 is my current record, control limited) and while I would be happy to test your antennas and have been considering buying a set to test (just have not decided which to get), my accomplishments were not achieved using your antennas.

Not trying to cause any problems, I do think you are doing great work and I appreciate your efforts and the help you are providing.

Thank you

 

[flight-of-eye]

ok, I am beginning to get the picture, however, if the tech spec on DJI site says that the extender is a <=17dBm, if I am correct is a amplified source, is it not? then how does adding two 9dBi antenna change the range. what is the rate of the stock antenna, per dBi rate? are the dBi antennas just increasing the amplification more then the two stock units, thus providing better range.

 

[themosttoys]

ok, I am beginning to get the picture, however, if the tech spec on DJI site says that the extender is a <=17dBm, if I am correct is a amplified source, is it not? then how does adding two 9dBi antenna change the range. what is the rate of the stock antenna, per dBi rate? are the dBi antennas just increasing the amplification more then the two stock units, thus providing better range.

dBm is a measure of power. Example chart: http://www.cpcstech.com/dbm-to-watt-con ... mation.htm

dBi is a measure of gain of an antenna with respect to an imaginary isotropic antenna - one that radiates equally in a spherical pattern (equal in all directions). One short reference: http://www.marcspages.co.uk/tech/antgain.htm

EDIT: BTW, yes, the repeater (range extender) and the camera are both amplified. DJI states 17dBm (50mw) but I and others have tested this to actually be over 21dBm.

 

[PVFlyer]

I have noticed that a few have only used one feed for the extender. Does it make a difference, why and which one? Why not tap both antenna? Would that not double your output. I have seen some use two 9db out of the extender, will this accomplish the same effect?

The phantom range extender and camera use a diversity transmitter and reciever. Using two antennas will not increase range it just gives you a better chance at having a constant signal as it will use whichever has the best signal. You can also mix and match a directional with an omni directional which is the most useful config.

PVFlyer has asserted that the Phantom 2 Vision wifi implementation is MIMO (802.11n). If this is in fact the case, then using two of the same CP antennas 180 degrees out of phase (as the ones in the repeater are) would in fact be an improvement in range and reliability (and may in fact explain why the two relatively poor antennas in the stock repeater work as well as they do). It might also help to explain why some are having such good success with two linear antennas as MIMO actually works better with multipath. I have not bothered going down this path, but if someone did (Ex: FPVLR is working on a set of his half dome antennas mounted 180deg out of phase) it might bear new fruit.

Edit, BTW, it is worthwhile mentioning that PVFlyer uses two of his home brew CP helicals with a MIMO setup to achieve his range on the stock P2V.

I "bet" or "guess" P2V is using 802.11n MIMO per my observation, though DJI has never disclosed such spec. If you look at my setup, I use a pair of helical with 2 wavelength (~25cm center-to-center) apart in 180-degree out of phase.

In general speaking, 802.11n MIMO home router can achieve 50%-100% more range (with the same output power as 802.11g) by diversity gain AKA multpathing.

 

[flight-of-eye]

ok, I am beginning to get the picture, however, if the tech spec on DJI site says that the extender is a <=17dBm, if I am correct is a amplified source, is it not? then how does adding two 9dBi antenna change the range. what is the rate of the stock antenna, per dBi rate? are the dBi antennas just increasing the amplification more then the two stock units, thus providing better range.

It's not just a matter of gain, but also a matter of noise. BTW I just got my second customer who used only a parasitic helix on the extender, LHCP 9.3 dBi and he reported 3000ft in FPV mode, that's consistent with the 3000+ft obtained with the 6.5 turns (which is capable of quite a bit more).

At this point, seeing this consistency I am even more convinced of the good performance of the dual setup.

I am thinking about a better solution still, but I will not spill my beans, as I have received tens of orders of LHCP solutions from HK , Taiwan, and China, so I am a bit afraid about clonation.

I am a procrastinator, I always save the best for last. As soon as reports of ranges with pinwheels installed on the camera itself come in, I will be able to calculate exactly what needs to be done to produce a consistent 10,000 ft which is my goal. Of course not having one DJI mylsef slows me down quite a bit, but having many testers who trust the antennas gives me an edge too in understanding.

TOny

dual, as in two antenna on extender or two/two = TX/RC.

 

[ClimbrJohn]

MIMO = multiple in multiple out

He means two 2.4 GHz antennas on the WiFi AP and two 2.4 GHz antennas on the P2V.

DUEL, as in two antenna on extender or two/two = TX/RC.

 

[flight-of-eye]

MIMO = multiple in multiple out

He means two 2.4 GHz antennas on the WiFi AP and two 2.4 GHz antennas on the P2V.

DUEL, as in two antenna on extender or two/two = TX/RC.[/quote]

right, two on the tx= transmitter/extender and two on rc= receiver/UAV

 

[themosttoys]

MIMO = multiple in multiple out

He means two 2.4 GHz antennas on the WiFi AP and two 2.4 GHz antennas on the P2V.

DUEL, as in two antenna on extender or two/two = TX/RC.[/quote]

right, two on the tx= transmitter/extender and two on rc= receiver/UAV

Wifi is bidirectional. Both sides are both RX and TX.

 

[ClimbrJohn]

Correct. I think what he means is, there are 7 antennas total:

(2) 2.4 GHz on P2V (FPV)
(2) 5.8 GHz on P2V (control)
(2) 2.4 GHz on WiFi AP
(1) 5.8 GHz on remote controller

By utilizing MIMO (4 total antennas) on both the WiFi AP and P2V camera it might increase range/bandwidth of FPV.

Wifi is bidirectional. Both sides are both RX and TX.

 

[flight-of-eye]

MIMO = multiple in multiple out

He means two 2.4 GHz antennas on the WiFi AP and two 2.4 GHz antennas on the P2V.

DUEL, as in two antenna on extender or two/two = TX/RC.

yes, total 4 antennas, as in its original configuration, but with a clever trick.

And yes, these are transceivers, on some routers, one transceiver can be configured to only transmit and the other one to only receive... or they can be configured for diversity.

thank you for the lesson. It really opened things up in a better perspective. I am going with the low cost 9dbi dual on the
extender for now. when I get use to flying without line of sight, then I will be ready to upgrade. just want to be ready for when I feel a tad bit eager to push the limits. still get nervous when I look up and cant see were its at, then look down and have no signal.

 

[ClimbrJohn]

I get nervous too until I enable IOC and use the home lock mode. Once enable, simply pull back on the right stick and the P2V will come back to you regardless of orientation.

More info: http://wiki.dji.com/en/index.php/Naza-M ... on_Control

still get nervous when I look up and cant see were its at, then look down and have no signal.

 

[themosttoys]

I get nervous too until I enable IOC and use the home lock mode. Once enable, simply pull back on the right stick and the P2V will come back to you regardless of orientation.

More info: http://wiki.dji.com/en/index.php/Naza-M ... on_Control

I always caution folks getting into IOC flight before they are ready (and if you are nervous, you are NOT ready.)

Better options:
1) Even when video is lost, you may still have telemetry. If you still have telemetry, enable "radar" by tapping the artificial horizon in the lower left of the screen. Use that to orient yourself. Point the arrow at the center of the screen and fly forward. This will bring the P2V back to you.
2) Rather than using Home Lock, why not just enable RTH (turn off controller). Then when back in contact turn controller back on?

One thing to remember is that maximum flight velocity in Home Lock and RTH is less than you are use to. So if you flew out and are low on battery you may not have enough to get back in HL / RTH.

My reason for bringing all of this up is that Course Lock is one click from Home Lock and has a VERY different result when pulling back on the stick. If you are beyond LOS and have no connection and you are nervous and make a mistake (stop in Course Lock rather than all the way in Home Lock) you could make a bad situation MUCH worse and not know it until it's too late.

To each their own. Happy flying.

 

[flight-of-eye]

I get nervous too until I enable IOC and use the home lock mode. Once enable, simply pull back on the right stick and the P2V will come back to you regardless of orientation.

More info: http://wiki.dji.com/en/index.php/Naza-M ... on_Control

I always caution folks getting into IOC flight before they are ready (and if you are nervous, you are NOT ready.)

Better options:
1) Even when video is lost, you may still have telemetry. If you still have telemetry, enable "radar" by tapping the artificial horizon in the lower left of the screen. Use that to orient yourself. Point the arrow at the center of the screen and fly forward. This will bring the P2V back to you.
2) Rather than using Home Lock, why not just enable RTH (turn off controller). Then when back in contact turn controller back on?

One thing to remember is that maximum flight velocity in Home Lock and RTH is less than you are use to. So if you flew out and are low on battery you may not have enough to get back in HL / RTH.

My reason for bringing all of this up is that Course Lock is one click from Home Lock and has a VERY different result when pulling back on the stick. If you are beyond LOS and have no connection and you are nervous and make a mistake (stop in Course Lock rather than all the way in Home Lock) you could make a bad situation MUCH worse and not know it until it's too late.

To each their own. Happy flying.

I agree. I have switched to NAZA and comfortable with its use, however, still use the RTH as my go to. I am quite comfortable flying and feel close to the next step, just not to sure about the FPV aspect and want the added range until I can fly beyond LOS and not be nervous. As with all things in life, baby steps. I would love to go big and hit the 2mile zone tomorrow but 1300.00 is a lot to train on. My PV2 was a gift and I would crumble if it came down.

 

[flight-of-eye]

Ok, I had ordered two of these and they came today, they are 9dbi. I did the mod and test flew to 1500ft with good video.

My question is this, if they are omnidirectional then is my setup overkill? Do I need two or can I just run with one and use one of the stock extender antennas as well? If that is possible then I will use the other for the tx.

 

[themosttoys]

Ok, I had ordered two of these and they came today, they are 9dbi. I did the mod and test flew to 1500ft with good video.

My question is this, if they are omnidirectional then is my setup overkill? Do I need two or can I just run with one and use one of the stock extender antennas as well? If that is possible then I will use the other for the tx.

It is no problem, you do not need to replace both antennas.

 

[flight-of-eye]

Ok, I had ordered two of these and they came today, they are 9dbi. I did the mod and test flew to 1500ft with good video.

My question is this, if they are omnidirectional then is my setup overkill? Do I need two or can I just run with one and use one of the stock extender antennas as well? If that is possible then I will use the other for the tx.

It is no problem, you do not need to replace both antennas.

will I get the same effect with just one? I watched the antenna 101 video today and it seems as though one would do the same as two. Same antenna, same range, same "bubble" as per say. I guess the only thing would be if one was vertical and one horizontal then the polarization would match. but seeing as the drone never really "banks" then is that even required?

 

[themosttoys]

Ok, I had ordered two of these and they came today, they are 9dbi. I did the mod and test flew to 1500ft with good video.

My question is this, if they are omnidirectional then is my setup overkill? Do I need two or can I just run with one and use one of the stock extender antennas as well? If that is possible then I will use the other for the tx.

It is no problem, you do not need to replace both antennas.

will I get the same effect with just one? I watched the antenna 101 video today and it seems as though one would do the same as two. Same antenna, same range, same "bubble" as per say. I guess the only thing would be if one was vertical and one horizontal then the polarization would match. but seeing as the drone never really "banks" then is that even required?

Polarization is not an issue, the P2V wifi is circular polarized. There is a small chance that you will get slightly better range with two antennas due to MIMO, but with those antennas I doubt it will amount to much. Give it a try and report your findings. BTW you will get more range flying sideways than by using both antennas.

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