This range test was done with stock P2V aircraft and homebrew LHCP helical antenna. I'm probably the first one in this forum figured out Vision camera using LHCP microstrip patch with 802.11n MIMO (obviously DJI engineers designed & knew that). Thus, I made a pair of LHCP helical to match the camera antenna for optimal performance.
UPDATE 05-Apr-2014: I lost my P2V on 22-Mar due to unknown reason (maybe sudden power loss or auto-land) during RTH. As I recalled in the past few months, she 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 pilots 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 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 forward (not sideways) with legal RF power.
I'm proud of all her achievements. Meanwhile, I have been waiting patiently for new P2V+ release.
UPDATE 22-Feb-2014: I replaced a stacked microstrip patch for 5.8G transmitter. It offers longer control range as expected (estimated 4 KM) until FPV video dropped out at 2.7 KM. After FPV dropped, I tried to yaw P2V 90-degree (5.8G control link worked well) and hoped to regain Wifi connection but it did not help, so I initiated RTH flying back. There was a bit raining with 82% humidity, which is no good for RF propagation. I'm also aware a building (highlighted in yellow square) may block the LoS.
[youtube]http://www.youtube.com/watch?v=l5ZCi2Bp9RU[/youtube]
Video is stabilized by YouTube.
UPDATE 3-Feb-2014: I did another range test. Vision App showed CONTROL SIGNAL LOST of 5.8G transmitter at 2.27 KM and triggered RTH, video downlink was still fine though.
[youtube]http://www.youtube.com/watch?v=9qaMw5knKWs[/youtube]
Video is stabilized by YouTube.
Initial Post 28-Jan-2014
[youtube]http://www.youtube.com/watch?v=lKWMeL-i-DI[/youtube]
Video is stabilized by YouTube.
UPDATE 05-Apr-2014: I lost my P2V on 22-Mar due to unknown reason (maybe sudden power loss or auto-land) during RTH. As I recalled in the past few months, she 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 pilots 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 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 forward (not sideways) with legal RF power.
I'm proud of all her achievements. Meanwhile, I have been waiting patiently for new P2V+ release.
UPDATE 22-Feb-2014: I replaced a stacked microstrip patch for 5.8G transmitter. It offers longer control range as expected (estimated 4 KM) until FPV video dropped out at 2.7 KM. After FPV dropped, I tried to yaw P2V 90-degree (5.8G control link worked well) and hoped to regain Wifi connection but it did not help, so I initiated RTH flying back. There was a bit raining with 82% humidity, which is no good for RF propagation. I'm also aware a building (highlighted in yellow square) may block the LoS.
[youtube]http://www.youtube.com/watch?v=l5ZCi2Bp9RU[/youtube]
Video is stabilized by YouTube.
UPDATE 3-Feb-2014: I did another range test. Vision App showed CONTROL SIGNAL LOST of 5.8G transmitter at 2.27 KM and triggered RTH, video downlink was still fine though.
[youtube]http://www.youtube.com/watch?v=9qaMw5knKWs[/youtube]
Video is stabilized by YouTube.
Initial Post 28-Jan-2014
[youtube]http://www.youtube.com/watch?v=lKWMeL-i-DI[/youtube]
Video is stabilized by YouTube.