Stock P2V 2.7 KM (8,850') Long Range Test
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Re: Lost my P2V
After scanning the video for a few days by a custom scanner program, my P2V was spotted about 2 meters away from the pond (somewhere highlighted in blue, just a few pixels showing in the video for less than a second which is no way to spot her by human eyes). Last Saturday morning (a rainy day), my friend flew his P2V to the pond and took a picture as a proof right after a thunder storm. She showed up at the edge of the pond (highlighted in red), probably the rain carried her there. My friend sent such picture to me (I was not there) during his departure of the field, because of another thunder storm heading there. I drove to the field in afternoon right after the thunder storm over, but I was no longer be able to find her. It's very likely the **** rain pushing her into the pond.
The shame is I knew her there (located by both GPS and Wifi Analyzer just about 10-20M away) but couldn't find her. I spotted her, but couldn't save her eventually. I lost her forever. RIP my little P2V, I will always miss you.
PVFlyer said:
After scanning the video for a few days by a custom scanner program, my P2V was spotted about 2 meters away from the pond (somewhere highlighted in blue, just a few pixels showing in the video for less than a second which is no way to spot her by human eyes). Last Saturday morning (a rainy day), my friend flew his P2V to the pond and took a picture as a proof right after a thunder storm. She showed up at the edge of the pond (highlighted in red), probably the rain carried her there. My friend sent such picture to me (I was not there) during his departure of the field, because of another thunder storm heading there. I drove to the field in afternoon right after the thunder storm over, but I was no longer be able to find her. It's very likely the **** rain pushing her into the pond.
The shame is I knew her there (located by both GPS and Wifi Analyzer just about 10-20M away) but couldn't find her. I spotted her, but couldn't save her eventually. I lost her forever. RIP my little P2V, I will always miss you.
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I feel ya brother! I flew mine right into a pond. I jumped in after it and after about 30 minutes found it! I still flies!! I would consider getting a pool net with long pole and attempting to recover it...
Geo
Geo
After my P2V went down a couple of weeks ago and I could not rescue her eventually, I was a bit depress for a few days.
As I recalled in the past several months, my P2V had done so many wonderful jobs. All her previous flights were splendid. I would like to recap her achievements.
1. She has proved Vision camera/repeater antenna is LHCP though DJI has never released such technical data. This crucial finding benefits the whole P2V community, especially those long range P2V flyers as well as FPV antenna makers. There are probably dozens of LHCP antenna orders flooding to those antenna makers all of a sudden.
2. She has proved Vision Wifi is MIMO instead of diversity system. Many conventional FPV flyers are still unaware the power of MIMO. The beauty of MIMO is to let you fly longer range with less RF power, thus let you fly long range "legally". In Hong Kong, the legal EIRP (Effective Isotropic Radiated Power) limit of 2.4G is 4W (36dBm). Imagine, if I put a 1W (30dBm) booster onto my repeater and hook up a 9dBi helical, the EIRP is 8W (39dBm), which is double the legal EIRP limit - "illegal". I bet the FCC rules in the US, the legal EIRP limit of 2.4G is the same 4W, while it maybe even lower in some European countries.
3. She has been still holding the 2.7 KM range record for a stock P2V (un-modded) aircraft flying FPV straight forward (not sideways) with legal RF power.
I'm proud of all her achievements. Meanwhile, I have been waiting patiently for new P2V+ release.
As I recalled in the past several months, my P2V had done so many wonderful jobs. All her previous flights were splendid. I would like to recap her achievements.
1. She has proved Vision camera/repeater antenna is LHCP though DJI has never released such technical data. This crucial finding benefits the whole P2V community, especially those long range P2V flyers as well as FPV antenna makers. There are probably dozens of LHCP antenna orders flooding to those antenna makers all of a sudden.
2. She has proved Vision Wifi is MIMO instead of diversity system. Many conventional FPV flyers are still unaware the power of MIMO. The beauty of MIMO is to let you fly longer range with less RF power, thus let you fly long range "legally". In Hong Kong, the legal EIRP (Effective Isotropic Radiated Power) limit of 2.4G is 4W (36dBm). Imagine, if I put a 1W (30dBm) booster onto my repeater and hook up a 9dBi helical, the EIRP is 8W (39dBm), which is double the legal EIRP limit - "illegal". I bet the FCC rules in the US, the legal EIRP limit of 2.4G is the same 4W, while it maybe even lower in some European countries.
3. She has been still holding the 2.7 KM range record for a stock P2V (un-modded) aircraft flying FPV straight forward (not sideways) with legal RF power.
I'm proud of all her achievements. Meanwhile, I have been waiting patiently for new P2V+ release.
Funny this thread just popped back up. I tried for a distance record today and got to between 2.6 and 2.7km - a big jump from my previous record of 1.92km. Unforunately Flytrex decided not to record the data so I had to find the spot it turned around in the video and used Google's distance measuring tool to get 2.68km approx.
This is with a stock transmitter and P2V. The repeater has my trusty 5dBi omni and 9dBi directional cheapo TP-link antennas. It was powered from a USB power pack during the flight, I had fresh Duracell Ultras in the transmitter and I flew at 600' instead of 350 or 400 like usual. It was really amazing - even though I had to fly sideways after 1km, I had decent FPV until about 1.6-1.8km, then just continued, getting telemetry and occasional frames of video until it turned around. At the furthest distance the WIfi dropped a few times but regained. Then flying straight at me I had nothing for a while, but around 2km I got telemetry back intermittently, then FPV around about 1.5km - it took a long time until the N/A turned into a number! That is so reassuring when you see distance numbers that decrease finally. Returned with 48% on the battery and the video was 12 minutes long. I think the big difference here was altitude - I had never tried flying that high before for these tests.
Will try again with Flytrex working for some evidence. I couldn't figure out what stopped it from recording. It wouldn't record to the normal card, but would to another. So I formatted my normal one (the 4GB that came with the P2V) and now it writes. I only had 84 .FPV files on there totaling something like 45MB. I'll ask the Flytrex guys if they have an idea.
This is with a stock transmitter and P2V. The repeater has my trusty 5dBi omni and 9dBi directional cheapo TP-link antennas. It was powered from a USB power pack during the flight, I had fresh Duracell Ultras in the transmitter and I flew at 600' instead of 350 or 400 like usual. It was really amazing - even though I had to fly sideways after 1km, I had decent FPV until about 1.6-1.8km, then just continued, getting telemetry and occasional frames of video until it turned around. At the furthest distance the WIfi dropped a few times but regained. Then flying straight at me I had nothing for a while, but around 2km I got telemetry back intermittently, then FPV around about 1.5km - it took a long time until the N/A turned into a number! That is so reassuring when you see distance numbers that decrease finally. Returned with 48% on the battery and the video was 12 minutes long. I think the big difference here was altitude - I had never tried flying that high before for these tests.
Will try again with Flytrex working for some evidence. I couldn't figure out what stopped it from recording. It wouldn't record to the normal card, but would to another. So I formatted my normal one (the 4GB that came with the P2V) and now it writes. I only had 84 .FPV files on there totaling something like 45MB. I'll ask the Flytrex guys if they have an idea.
nhoover said:
You may try to add another 9dBi directional to replace the 5dBi omni. The additional 9dBi panel can be mounted 90-degree against the original panel, which forms a dual-polarized antenna array. This could make use of MIMO for longer range and stabler FPV, and hope you don't need to fly sideways during long range flights.
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PVFlyer said:
I see what you are saying but I was mainly questioning what effect will occur if I velcro mount the half sphere to the panel of the extender. So I would have one stock antenna operating in the extender and the half sphere operating on top of that. Do you see any issues with this setup?
gfredrone said:
If the reflector (ground plane) of your half sphere covered the repeater, you then have only 1 antenna (the half sphere) operating. The RF signal of stock microstrip panel insider the repeater is blocked. I'm afraid the RF signal would not stack up in that way as you expected. Would it be easier if you post a picture to illustrate your setup?
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PVFlyer said:
It's being delivered today so I don't have a pic for you yet.
I was thinking like you that the reflector of the half sphere would block the extenders internal antenna if stacked on top. I'll probably figure out a way to mount it to the side then, as well as try it both ways to see if there are any range differences.
I'll post a pic when I have everything set up.
PVFlyer said:
Interesting idea. Sounds like a cheap experiment - just ordered a second directional!
nhoover said:
It's important to mount the 2 panels 90-degree against each others (say one is vertical and the other is horizontal, or +/- 45-degree), especially when you mount them nearby to avoid interference. This will form a dual-polarized linear array. However, there is a -3dB loss when matching with LHCP antenna in the Vision camera.
Folks in the US need to be aware that it is illegal to alter the antennas used on either the transmitter or the WiFi. I know, everybody does it, but the fact remains, it is not legal.
From the FCC:
http://transition.fcc.gov/Bureaus/Engin ... t63rev.pdf
From the FCC:
http://transition.fcc.gov/Bureaus/Engin ... t63rev.pdf
Ok, I read the document.
Page 2. Section 15.23 and section 15.5 seems to suggest we can do these modification as long as it does not interfere to licensed radio communication.
And moving on to the 2.4 GHz and 5.8 GHz band...
2.4GHz, page 20. Section 15.231 (intermittent control signals), Section 14.247, Section 14.249
5.8GHz, page 22, Section 14.247, 14.249,
And using this equation from page 29... P = 0.3E^2
(this is for a simply calculation using a unity gain antenna G = 1, and 3 meter distance or D = 3).
P = transmitter power (EIRP) in watts
E = field strength in volts / meter.
You get the "E" value fro the 2.4GHz and 5.8Ghz section I find above.
Page 2. Section 15.23 and section 15.5 seems to suggest we can do these modification as long as it does not interfere to licensed radio communication.
And moving on to the 2.4 GHz and 5.8 GHz band...
2.4GHz, page 20. Section 15.231 (intermittent control signals), Section 14.247, Section 14.249
5.8GHz, page 22, Section 14.247, 14.249,
And using this equation from page 29... P = 0.3E^2
(this is for a simply calculation using a unity gain antenna G = 1, and 3 meter distance or D = 3).
P = transmitter power (EIRP) in watts
E = field strength in volts / meter.
You get the "E" value fro the 2.4GHz and 5.8Ghz section I find above.
gfredrone said:
It looks very nice and small form factor.
After the first range test, you may try to shift the half sphere further away from the stock internal antenna. I suggest to segregate them minimum 1 wavelength (12.5cm) to maximize diversity gain, if feasible.
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