ESP8266 Antenna Mod - extend WiFi range

Tags: #<Tag:0x00007f745f771520> #<Tag:0x00007f745f771458>

Howdy!

I was watching this video from one of my favourite makers on YouTube when I came across the following point in the video:

It looks like an ESP8266 but it’s not. It’s an NRF24L01 module, which is a 2.4 GHz communications module. Nevertheless, 2.4 GHz is 2.4 GHz, and this thing has antenna wires soldered onto it!

I’ve had problems with the WiFi range on the ESP8266. I’ve seen at least three distinct PCB antenna types. I’ve not been able to find anyone else making reference to these different types and how they perform, so here is my own anecdotal evidence.

In descending order of performance: Most sensitive, Bad, Awful.

The design to the left seems best by far. It also appears to have nearly twice the active area on the circuit board.

But, here’s the fun part. It never occured to me that I could simply cut the circuit board traces and solder my own wires on there as antennas!

I’ve done it and literally seen 10 dB signal improvement. Every 3dB is equivalent to a doubling of power, so 10dB is actually ten times the effective power. Marginal locations suddenly work flawlessly.

At first I used CAT5 networking wire strands, then once I examined it under the microscope and found that it looked like I had soldered freaking timber logs to the circuit board, I realized that 30 AWG wire-wrapping wire would be a better fit.

Here are some microscope photos of the process of modifying an ESP-01. Please note that I’m a novice at this, still learning the tools, so it’s not pretty… but it works like a charm.

Unmodified front:

Unmodified rear:

After some butchering with a utility knife:


58mm 30 AWG wires soldered on:


In the case of a NodeMCU board, which have the ESP-12 module directly mounted, there’s no easy access to the rear for the ground plane wire. In those cases, I’ve found that adding just an antenna wire without adding a ground wire is still worthwhile and did improve reception for me.

I used this online antenna length calculator to arrive at 58 millimeters, based on an entered frequency of 2450 MHz.

2 Likes

Why cut the on board antenna only to fill it back in with solder? Doesn’t that essentially repair the cut?

It’s not actually filled with solder, there’s just solder on both sides of the cut. I tried showing it in the photo but it doesn’t show as clearly in photos as it did in real life, probably due to the lack of depth. Looking directly into the binocular microscope there was plenty of clearance. :slight_smile:

:+1:

Here’s wishing I had a binocular microscope. :smiley:

2 Likes

I figured I would need one to work on any circuit board with surface mount components.

It can get expensive watching makers on youtube.

This is the one I have, after seeing it in this video.

It’s actually trinocular (binocular + camera port). I bought this camera, but it’s utter garbage:
Dim, noisy, narrow image.

The images I posted in this thread were actually taken by holding my phone in front of one of the eyepieces!

Maybe I should get a better camera (since that one is unusable) but I’m not sure which one, and they’re kinda too expensive to take a chance.

This one claims to have a sony sensor but it’s almost $500 bucks… that seems crazy to me in this day and age, considering that’s what the entire trinocular microscope was, how can a lens-less camera be so expensive?