CarPlay Drops? Try Shortening Your USB Cables

I have not been a happy CarPlay user for the last couple months. I'd started getting the occasional loss of connection with my previous 3rd party receiver, and it had just gotten worse when I switched in a new one. I'd connect my iPhone 5S, it would work for a few minutes, sometimes as long as half an hour, and then CarPlay would just disappear. Replugging it in would usually work, but typically for a shorter time. I'd taken to just listening to podcasts over Bluetooth.

Things I Tried

1. Switching from a 3rd party Lightning cable to an Apple original.
2. Putting the phone in low power mode (maybe it was a charging problem)
3. Just using Podcasts, avoiding Maps or Phone.
4. Turning off Bluetooth (I drove the half hour to work once without drops when I forgot my Apple Watch)
5. Updating to the iOS 11.1 beta.

What Worked

Replacing the 40 inch Lightning cable with a 4 inch cable. The phone might have been hanging from the USB socket, but it didn't drop over several days of commuting. 

I had installed the receiver myself, and had purchased a cable with a USB-A male to flush mounted USB-A female. It looked nice, mounted on the dashboard, but 6 inches would have been as good or better than 6 feet.

A 6 foot USB Auto Cable

All, I really wanted, the flush mounted socket

To sum up the cable run: 

• Cable embedded in receiver: 3Ft
• Flush mounted cable: 6ft
• Apple Lightning cable 3.5ft

So a bit over 12 feet. A quick googling indicates that USB 2 has a maximum length of between 3 and 5 meters (10-16 feet), so 12 was starting to be a bit marginal, coupled with 3 separate cables, my oldish phone, and I could see where it might not be reliable.

Long term solution

I pulled out the overlong cable and replaced it with a 3 foot version. Fingers crossed; I've fooled myself into thinking I'd solved this a couple times before.