ESP8266 Community Forum

- Sat Apr 25, 2015 6:24 am #15583 Hello,

This is only a Warning.
At the Moment different Sellers are selling ESP-201 modules with wong Antennas.

The Antenna is only a few mm stripped, instead of Lambda/4 about 30 mm.
The better Antenna is a Cable with about 24 mm sleeve for the shield and 30mm core.

The wrong antennas have a limited reach.

Greetings,
Sam

- Sat Apr 25, 2015 8:46 am #15604 I think i got one of those. I did wonder that there was only such a short amount unshielded. Presumably i can cut more sleeve and shielding off with a knife? Not sure i understand what you mean by 24mm sleeve - at them moment the entire wire is about 15 cm long, are you saying that should be cut back to be just 54mm long?

- Sat Apr 25, 2015 10:13 am #15611 Hi TheSam

Do you mean that the antenna tail acts as an antenna?

- Sat Apr 25, 2015 10:34 am #15613 I add a Picture to show the wrong Antenna.

You can easily fix the problem:

Cut sleeve and shielding off with a knife and use the core as Antenna.
This should be Lambda/4 of the used frequency:
On 2.45 GHz we have a Lamda of 122mm, so you cut on 30.5 mm -> 30mm should work, too...

Sam

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