ESP8266 Community Forum

- Thu Dec 04, 2014 5:23 pm #4004 PCBs did finally came in today, and find some time for soldering them up. No time for testing yet :'(

Pictures :

IMG_20141204_201555.jpg

IMG_20141204_203627.jpg

IMG_20141204_203650.jpg

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- Tue Dec 09, 2014 3:46 pm #4423 FInally got around to test my board. At first they didn't power up and it took me a while to figure out what was happening; it appears I made a wrong footprint for the crystals and swapped the connection and preventing the module from booting up. After desoldering the crystal and resolder it with some wires the module boots up. Here is a picture of the repair:

_20141209_203544.JPG

I used a larger crystal which soldered much easy on

I also did some measurements of the signal strength using different antenna's i had lying around. I measure the strength using my phone (S4, CM11, wifi analyzer) next to the module and some distance away (3 walls and a floor, +-10 mtr apart). Not very scientific but it gives a ballpark figure.

IMG_20141209_200516.jpg

my module with chip antenna, -30dBm , -80dBm
my module u.fl antenna 1 (left), -30dBm, -60dBm
my module u.fl antenna 2 (middle), -20dBm, -65dBm
my module u.fl antenna 1 (right), -35dBm, -70dBm
ESP-01 module (pcb antenna), -25dBm, -65dBm
Claude board with chip antenna, -35dBm, -80dbm

The chip antennas work worse then the PCB, which I didn't expected. ALthough it wasn't measured too scientific Perhaps some antenna guru's could shed a light on this?

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- Fri Dec 12, 2014 8:45 am #4663

The chip antennas work worse then the PCB, which I didn't expected. ALthough it wasn't measured too scientific Perhaps some antenna guru's could shed a light on this?

congrats for having a working board. PCB antenna being better than chip antenna is OK.

For measurements you might want to take the following into consideration:
http://en.wikipedia.org/wiki/Radiation_pattern
http://de.wikipedia.org/wiki/Richtcharakteristik
and
http://en.wikipedia.org/wiki/Polarization_%28waves%29

Have a look on how they measure here: http://www.ti.com/lit/an/swra351a/swra351a.pdf (click on links to see measurements for each antenna).
Not expecting such details here but maybe this helps.

Edit:
Do you think that connecting the RESET pin is required or could it be floating due to internal pullup and due to not being required for programming?

- Fri Dec 12, 2014 10:19 am #4675

congrats for having a working board. PCB antenna being better than chip antenna is OK.

For measurements you might want to take the following into consideration:
http://en.wikipedia.org/wiki/Radiation_pattern
http://de.wikipedia.org/wiki/Richtcharakteristik
and
http://en.wikipedia.org/wiki/Polarization_%28waves%29

Have a look on how they measure here: http://www.ti.com/lit/an/swra351a/swra351a.pdf (click on links to see measurements for each antenna).
Not expecting such details here but maybe this helps.

I'm aware that antennas have different radiation patterns, but it was just a quick impression, but it is more real live IMHO then in a lab. Dont have the equipment to do it properly

Edit:
Do you think that connecting the RESET pin is required or could it be floating due to internal pullup and due to not being required for programming?

Dunno, but I read in the forums that the pullup is very weak, So I suggest to pull it anyway high with 10k, no suprizes then.