Quick post on Huawei CRC9 antenna jack.
This is a very small antenna connector found on some of Huawei’s 3G broadband modems.
The jack has a ground and two pads. They are NC (normally closed) meaning that when you attach an antenna they will open up and the RF circuit will feed the external antenna instead of the internal one.
I had to dig around a lot to find some info on this, and found a russian site with some info.
Detail of the connector:
Why is this relevant? Because i didn’t had a CRC-9 pigtail around and had to solder coax directly to the board. Yes, it works. No i don’t recommend. This was hooked up to my DIY yagi antenna.