Poor WiFi signal with Raspeberry Zero W

Question

I have recently bought Rasberry Zero W. Since I wanted to get original top quality item I bought it at PiHut.

Nevertheless, I still have problems with the unit; as it has incredibly poor WiFi signal. When about 2 m from the AP (one wall in between), signal power is only -72dBm to -82dBm depending on the unit orientation, as checked by iwconfig command.

I have tried two different SDcards, two different power supplies, without significant change. I also put my Raspberry Pi 3 on the same spot, signal power is -56dBm (I haven't tried different orientations, just for comparison). Finally using Wifi Analyzer for Android on my smartphone (Galaxy S10E), signal power is around -45dBm.

Is such small signal normal for Raspberry Zero W? Should I perhaps asked for a replacement?

Answer 1

I bought another Raspberry Pi Zero W.

With the same power supply, the same SD card as the first Raspberry Pi Zero W and on the same spot, signal is -44dBm to -49dBm. This is better than Raspberry Pi 3 and comparable to my smartphone.

The first Raspberry Pi Zero W is obviously faulty and I will send it back.