Why with wireless router 2 laptops side by side 1 has strong signal and 1 has we

1) Have you tried turning the laptops so that they are both at the same or optimum angle -- the antenna is usually in the lid around the screen -- it's angle to the direction of the router may affect signal strength.

2) Some wireless adapters may be more sensitive than others, sometimes later firmware or driver may cause one of two identical adapters to seem more sensistive.

3) The signal strength and quality indicators are not gospel. Apparent differences may merely be down to the way the displays are designed to express signal level.