Up until now, I haven't had much issues with image transmission loss. If anything it would come up once I got airborne or to a certain altitude.

On July 4th, I updated my Go App to version 3.1.13. My next flight after updating the Go App was on July 9th where I started experiencing No Image Transmission. I flew a total of 3 batteries that day in two different locations completely blind. I had no image on screen to reference what my camera was shooting. The night of the 9th, I noticed I had updates ready for my RC and Aircraft. So I updated my RC to version 1.9.2 and my Aircraft to version 1.11.20. Monday July 10th, I went out to do a test flight with the new FW installed. Again I had no image transmission scrolling across the top of my Go App. At this point, I am at a loss of words of what is going on.

Thinking I have a bad cable, I bought a brand new USB cable which that didn't fix the issue. It kept wanting to RTH because I had no image displayed.
Today I ran some more tests. I was told my MicroSD card could be corrupted which I just formatted it the night before when I put the new FW on there. So I used a different MicroSD card. The problem was still there. Someone told me to try and use a different device. I normally use my iPhone 6 with no issues. I then used my iPad Mini and once I had everything up and running, I FINALLY had a picture on my screen while the P3P was still on the ground. I launched it to about 30 meters and it held the picture but then my screen went to black and No Image Transmission started scrolling across the top of the Go App. Once I landed it, the image came back. In the settings it clearly said my signal was poor due to strong intereference. This makes 5 different flight locations, different USB cable, different devices, different MicroSD card and yet the same issue prevails!

I can't really blame this on the FW update because I was having these issues prior to me updating the FW.

I've watched several videos on Youtube that claim to have the fix for this but none of that works. I should also mention that I manually changed my channel to a different channel hoping to pull in a stronger image transmission signal and that didn't even work. I played with the Image Transmission Quality slider too and I didn't notice any difference with that.

I spoke to an Engineer at my job who works on Drones and he said it sounded like I have an issue with Lightbridge. I don't really know how to trouble shoot that other than the steps I already have taken.

If anyone has any suggestions I should try that I have not already mention, please let me know. This is very frustrating to say the least.

Would upgrading the antenna help with this issue? There are times the P3P is sitting on the ground and it will still have no picture on the screen so I am at a loss right now trying to figure this issue out!

So just to confirm this is a Phantom 3 Pro?

You may try to rebind the RC and the phantom. If it doesn't work, I think you have to send to DJI to repair. It really sounds like the lightbridge problem.

I ran into similar issues with my mavic. The only solve I've come up with so far is putting my devices (iPad mini 2 & iPhone 7 plus) in airplane mode. Once in airplane mode the issues no longer presented themselves.

The only reason I could come up with as a cause was notifications coming through the mobile device for some reason.

"Do not disturb" may offer a similar solution but I have not tested it as if yet. Hope it works for you as well! I know how frustrating this can be.

Usually when the app says there is a " no image transmission signal" this indicates a defect or malfunction of you gimbal/ camera video downlink and there is no direct way to fix this. But this is should be normally be repaired under warranty!

This "No Image Transmission" is a common problem across the board on P3P's and Inspire 1's

I currently have 1 Inspire 1 and two P3Pro's down, the last P3P to die had the same exact problems you had; no range and a broken image before it finally stopped.  If I had to guess - I would suspect this is a heat related problem which has terminated the life on the output finals and they are now beginning to fail.

Right now I'm waiting for an answer from someone, I'm just not sure who!

Regards - Mike