Wireless Display Adapter Disconnects

Could a new 4G phone do this? (When I'm next in the office I'll turn off my phone and give it a go.)

Sorry to hear that. As I mentioned, I tried this with Microsoft's WDA. From my limited experience, you seem to be running into some sort of interference that's terminating the connection. What you've described above is exactly what I also saw with the WDA. It might be an option to identify any other potential source of interference that operates in similar frequency band on the SP3 or the TV.

I'll give disabling Bluetooth a go. Hope it works.

My story: I had been using the Screenbeam with my SP3 every day without any problems. I updated the firmware on the Screenbeam and then started getting dropouts and failure to connect. At the same time my SP3 was replaced so I was then confused about whether the problems were due to the firmware upgrade or the new device. I purchased the Microsoft device ($100 in Australia) and the problems persisted so I returned the Microsoft device and downgraded the firmware on the Screenbeam. So now I'm back to the Screenbeam with the original firmware and a different SP3 but I'm still having the problems of failure to connect and dropouts when it does connect. Windows updates are all done so I'm assuming that I have the latest display drivers on the SP3. 

I use the Miracast extensively...several times a day. Onenote and the Screenbeam turn my tv into a whiteboard that I use with clients. 

Fingers crossed that disabling Bluetooth (that I rarely use anyway) will help. Thanks for the tip. I've been struggling with this for ages and it really has become a critical part of the way I do my job. 

Nope...no change. Disabling bluetooth didn't help.

Still doesn't connect properly. Will connect, but remain frozen on the screen that first appears. Or may freeze after a short while and then disconnect. Or works for a while but eventually disconnects.

I'll give disabling Bluetooth a go. Hope it works.

My story: I had been using the Screenbeam with my SP3 every day without any problems. I updated the firmware on the Screenbeam and then started getting dropouts and failure to connect. At the same time my SP3 was replaced so I was then confused about whether the problems were due to the firmware upgrade or the new device. I purchased the Microsoft device ($100 in Australia) and the problems persisted so I returned the Microsoft device and downgraded the firmware on the Screenbeam. So now I'm back to the Screenbeam with the original firmware and a different SP3 but I'm still having the problems of failure to connect and dropouts when it does connect. Windows updates are all done so I'm assuming that I have the latest display drivers on the SP3. 

I use the Miracast extensively...several times a day. Onenote and the Screenbeam turn my tv into a whiteboard that I use with clients. 

Fingers crossed that disabling Bluetooth (that I rarely use anyway) will help. Thanks for the tip. I've been struggling with this for ages and it really has become a critical part of the way I do my job.

I have been facing similar disconnects with the Microsoft wireless display adapter and within a few seconds of establishing the connection. While searching around, I came across a comment in the URL below which piqued my attention.

https://www.thurrott.com/hardware/1454/use-microsoft-wireless-display-adapter

Someone commented about interoperability issues with the wifi/bluetooth device on their PC. The suggestion was to disable IPv6. Disabling IPv6 however didn't make a lot of sense to me. So I went with the assumption that there might be an issue with bluetooth and disabled it on my PC.

After disabling bluetooth, the disconnect problem went away and the adapter works just fine. Check it out - however do note that your mileage may vary.