A teardown of the Switch Joy Con hardware by YouTuber Jon Downey seems to suggest that the problems some are experiencing with the left controller are due to a design limitation.
The machine has since even before launch been dogged by complaints regarding the signal strength of its left Joy Con controller. While plenty of users are reporting no problems whatsoever, a large number also claim to suffer frequent signal drops from the peripheral.
Some of these occur under extreme stress testing (I was in another room with the controller behind my back!”) but others claim that so much as putting their feet on a table even when very close to the console is enough to interrupt the signal.
The issue has been acknowledged by Nintendo, although the platform holder hasn't indicated whether it's a hardware problem or something that can be addressed by a software patch.
Now an investigation by Downey shows that the left Joy Con is designed very differently to the right. The latter features a dedicated Bluetooth antenna component that is plugged into the circuit board and positioned close to the casing and about half way down the controller.
The former, however, sees the antenna built in to the circuitry, and sat right at the top where a user's hand would grip. Adding to the potential problems, it's also positioned over the metal casing housing the joystick, which could cause some interference.
Adding strength to his claims, Downey seemed to be able to alleviate the problem by adding a copper wire antenna extender to the board that reached down toward the bottom of the controller where the signal is less likely to be stifled by a user's hand.
The result? The controller's connection stayed strong at far greater distances.
Obviously such procedures are warranty voiding and technically difficult, and are definitely not advised.
Take a look for yourself: