"Hello Patrick,
is this possible to use external magnetometer?
it is necessary for my big quad.
next question is that,the ppm problem on raspberry pi zero since ver 3.5,is it fixed? "

"@ Andrew,J-tech use TCP/IP protocol , does it cause to high latency for replay the lost packet when the copter far from the home position? I think that TCP/IP is not the correct choice for HD video stream in air vehicle.what's your experience about…"

"@patrick ,Hi, in previous page you mention that use 2 watt transmitter on your UAV, Can I ask what 's your transmitter?
Do you use a usb dongle and 2 watt Amp or your transmitter has 2 watt RF output?"

"@Patrick,Is this Possible that ,Replace Rpi Instead of laptop on Ground station and using the Gstreamer for FPV and recording? If yes, what is the command that I use for ground station's RPi?"

"@Partick, 
Thanks for your quick answer. raspberry pi in my test also about 150 ms latency But raspberry pi camera or C920 not support zoom option,that I need.the general IP Camera with zoom option in Market Has Too Latency about 500-800 ms , that…"

"@Partick, the wifi hd camera usually has large latency about 0.5 or 0.8 secend. 
 Is It Possible that use analog camera (because optical zoom) and capture device on raspberry pi with wifi system? 
because there are many analog cameras with optical…"

"@patrick, 
according to My previous experience for analog video link, I could get 5 km range and good video quality with 5.8ghz ,2w boscam transmitter that used cloverleaf antenna on copter and homemade Ibcrazy 6 turn (10dbi) helical on receiver…"

"@Patrick Poirier, I Use 433 Mhz radio link.@Patrick,no I'm not flying with a lot of sources is that frequency range.I know about high frequency properties and antenna importance, but I don't know that 2.4 ghz does enough bandwidth for HD video and…"

"@Patrick,
thanks for your answer about C920 camera.
Do you have any experience with 2.4 ghz?I know 2.4 ghz may that interference with many other sources of wifi,I want to know, 2.4ghz is suitable for HD video transmission?I test the 100mw 2.4ghz…"

"@Patrick, very cool,do you have any video with C920 camera?"

"@Patick, Thank's again for your useful post."

"@Patrick,Thank you. what's the resolution that latency is 10-20ms more than picam?"

"@Patrick,I want to know the latency of C920 is suitable for FPV? I know that the original PI camera with the Raspi latency is about 120 ms that is good.
please compare the latency of PI camera and C920.
Thanks a lot."