Antenna extender for sim900a module

[A2]

Hi,

I am using sim900A module, for sending SMS , similiar to this:

http://www.aliexpress.com/store/product/Dual-frequency-sim900a-replace-Sim900-module-development-board-gprs-module-gsm-learning-board-better-than-sim300/835168_1328189947.html


1. problem is there is no datasheet available, all are either from china or taiwan

2. The antenna is very small. I have to increase the antenna length by 1m, is there antenna expander which I can use without losing the signal strength.