Little bit of history, I am running a Phantom v2 and the H4-3D gimbal along with a gopro hero 4 black edition with aniti interference board. I recently purchased a FPV kit which included:
Vonista Black Pearl 7 channel diversity reciever (made for immersion/fatshark transmitters as stated on there website) - purchased from FirstPersonView.co.uk
ImmersionRC 600mW Tx - purchased from FirstPersonView.com
RCHP Fatshark Spironet pair v2 - purchased from firstpersonview
DJI iosd mini - purchased from DJI.
Iosd/fpv Plug and play cable (which has ground cable already setup to the transmitter) - purchased from firstpersonview
So I got everything setup and working, I recieve a picture. However and here is the problem, when ever I move the drone or move the black pearl monitor even right infront of one another, I get what I can only describe as interference/flickering sort of like when your old tape recorder would be on pause or was eating the tape lol it keeps flickering badly. When ever I fly the drone it starts to get worse (much worse) when the drone gets further away.
All I have to do in the house is move the BP Monitor and I get that flickering. It flickers like mad once I get out to 100m. I did notice the iosd info on the screen the bit that tells you what height the drone is at flickers from 0 to 1m consistantly.
Is this a grounding issue as the PnP cable should already be grounding the video and transmitter.
This video shows you at 2 min 40 sec what I mean about the grounding.
describes how you can solder a wire onto the ribbon cable and attach it to the power-in, to the transmitter. However my pnp cable already has a black wire into that slot.
I was facing the same problem with my P2.
Black pearl monitor, flysight tx 700mw, GoPro 4 and IOSD.
Heavy flickering screen when the drone was only 15m away!
I noticed there was no problem with motors off. Drone static on table and walked 150m out with the monitor... All perfect!
So there had to be some kind of interference...
Opened the drone and noticed that all cables coming from the Video -TX were very close to the main power cables (thick red and black coming from battery and soldered on the mainboard)
I moved away the video cables from the main power cables and tested again this afternoon.
Not a single flickering and flew out 500m with still perfect image on the screen!
So check those wires inside the fuselage.
Hope this helps.