Why do Wi-Fi repeaters slow down speed at close range?
If you have purchased a new Wi-Fi repeater system, whether one from your local store or a more complex kit like the Alfa WiFi Camp Pro 2, you may have decided to give it a test run at home in the same room as your router.
You may have been surprised to see that at 100% signal and not much distance between your computer, router and your repeater, your speed through the repeater was slower than when directly connecting your PC to your home router's Wi-Fi signal. But the repeater was supposed to make everything faster, you thought.
Repeaters are designed to take a fair/weak Wi-Fi signal and rebroadcast it (repeat it) as a new Wi-Fi signal that will cover additional area where signal could not previously be received well. When you setup a repeater at close range to a router, you are detouring data packets through an unnecessary route. The best way to describe it comes from this post we saw on CNET forums:
PC to router = 1 request and 1 reply.
What exactly does this mean? Wi-Fi is a half duplex technology. This simply means data is sent then received (with an Ethernet cable connection, data is sent and received at the same time). When you use a repeater to extend coverage, you are creating a second half duplex signal that data must travel through, which slows down packet rates. When you set up your repeater where coverage is fair or weak, it will extend signal further to areas where you could not get signal, and you will go from having weak signal to having a stronger signal and faster data speeds. However at close range, the repeater cannot serve its purpose of extending coverage because coverage is already good, and actually will cause your speed to be slower.
Bottom line- definitely test your repeaters like the Alfa Camp Pro 2 inside your home before going on the road to familiarize yourself with the setup process and ensure all hardware is working. But don't rely on close range speed tests to determine if the equipment is doing its job.