ESP8266 Community Forum

- Tue Feb 10, 2015 2:24 am #9372 Thanks Pigs Fly for confirming that simply just plugging in an external antenna reduces performance since if both the ceramic and the external antenna are active they represent poor impedance matching.

The designer of the esp-07 must have had some idea as to how the external antenna was to be used so it is unfair that there is no documentation as to how to proceed.

- Tue Feb 10, 2015 6:56 am #9385

Ceramic only: pretty steady at -80 to -79
Unmodified module with external attached: slightly better at -79 to -76
Removed cap, external attached: far better at -72 to -62 and directionality was evident.

confirming that simply just plugging in an external antenna reduces performance

Improves, not reduces, at least on my module and with the antenna I used. Lots of variables, but I could see how it could drop performance with a different antenna without removing the cap (or the ceramic antenna itself).

Those numbers are in dBm (sorry, should have made that more clear I suppose, but all routers normally display signal strength in dBm). Larger numbers represent a better signal, so -62dBm is much stronger than -80dBm. Six times better to be exact since every 3dBm is a doubling of power.

Maybe an RF expert will jump in and offer a different take on the situation.

- Thu Jun 25, 2015 5:59 pm #21697 Hi All,
So the upshot is remove the small coupling capacitor that connects to the ceramic antenna and the external antenna works OK?

What is the outdoor range like with the ESP-07 and 433MHz external antenna?

Im just about to order some ESP-07's + antenna's for a project so fingers crossed :-/

Ray

- Sat Jul 25, 2015 1:54 am #24209 > 433MHz external antenna

You must use 2.4GHz antennas! If you use a wrongly tuned antenna at best you'll get awful performance, at worst it'll reflect too much power back into the transmitter and damage something.