** high performance indoor/outdoor antenna wanted **

interested, i need one of this gear to extend/improve wifi signal, my question:

1. if there is no blockage (condo), how far can i receive the signal from other end?
2. if there is free hotspot nearby, can i extend it in my room?
3. if i have an extra wifi router, can i plugin any of this gear act as repeater/extender? what type of router can i use?
4. performance?


Thanks.