Hi Fellas, I am using Comfast WR150N wifi router cum repeater. I want to use my wifi in the library down the street (100 meters away). As mentioned on the box wifi uses a 2dbi antenna. But I hardy get any signals in the library. Is there any way that I could connect a high dB antenna to the wifi and increase the range? I know that there are some models especially for long range  available in stores (like TP-Link TL-WA5210G) but Since my nature of work in the library is temporary I don't want to invest in those routers. So basically what I am looking for Is mod/hack so that I can radiate more power.
PS: I have seen some DIYs of using parabolic reflectors  to boost signal strength. But what I am looking for is a higher power antenna.

I have Uploaded my Router pic here http://s22.postimg.org/6n5xlknpt/image_31554.jpg

(Last edited by shikhar623 on 18 Jul 2015, 15:18)

Looks like you could remove C81 and solder a pigtail there or left of C78. Then you can connect any antenna you like.
Parabolic reflectors are providing pretty much the highest gain. See http://wiki.openwrt.org/doc/hardware/antennae for further information.

Hi MBS. Thanks for a reply.
What I have  understood till now is:
Step 1: solder  (  male hfl) to the terminal marked Red in  this image
Step 2: insert the pigtail cable (female ufl side)  into the male ufl (soldered on the PcB)
Step 3: connect the antenna to the free end of pigtail cable(sma) .
Please correct me if I'm wrong. 

Also Pls answer some queries.
1. From what I have studied i think that my signal strength will depend both upon the (a) current provided into the antenna and,  (b) the antenna direcitvity 
So is there anything i can do to increase the current provided to the antenna? (any high frequency amplifier available?) 
2. What are these component marked C**? Capacitors?
3. You gave two locations to connect my pigtail cable. Is it a better option to use this red marked terminal than  removing the C81 and using that terminal.
4.  what is that golden/copper colored U shaped engraving on the top right corner of the PCB..?   the antenna of the router?
5. I want to maximize my range so I will  be using both external antenna and a parabolic reflector. Is it advisable?.
6. In The link you provided: the two links under the tile 'Antennas'  are not working. Can you provide the alternative links. 
Thanks

I thought more about directly soldering a pigtail to the pcb, without the need for a connector. But that is up to your needs. Just remember to remove C81, so the pcb antenna will be disconnected.
About your questions:
1. I think active antennas (with amplifiers) are available, but usually not recommended. Amplifying the host signal won't help you, if the clients signal strength is too low for the host to receive anything.
2. C marked components are capacitors.
3. It seems TP-Link designed that red marked terminal to test the radio part. So, this can be reused. I expect they also do their tests with C81 removed. The capacitors in the group of C85 are for adapting the unusual impedance of the pcb antenna.
4. Yes, that is the pcb antenna.
5. Sure. Check http://trevormarshall.com/biquad.htm and http://wlan.wavesurf.at/index.php?optio … &gid=4
6. Seems like some pages are not maintained any longer. But the internet doesn't forget. You just need to ask archive.org

1. In the case of direct soldering of ufl cable to the PcB since that portion will be left unshielded will it cause any degradation of the signal.?
2. Since the ufl cable has two terminals inner wire (signal)  and outer shield (ground). Where should the gnd be soldered?
3. I searched for some antennas online. There are antennas varying from 7db to 10db gain. Is that the max gain I can get from external antenna.? ..
4. Can I simply go for an antenna with  highest dB?. .does choosing an antenna  beyond certain dB degrade the signal quality??
5. I have this DTH reflector.  www.solid4you.in/index.php?route=product/product&path=20_64&product_id=198
I hope that will work..?
6. Which antenna should I connect to pigtail,  this  www.zdacomm.com/images/stories/catalog/2.4ghz-rubber-duck-antenna.jpg
or
www.trevormarshall.com/bq-front-thumb.jpg??

(Last edited by shikhar623 on 25 Jul 2015, 14:14)

1. If done right, there should not be an impact. See how TP-Link does it with the 1043ND: http://wiki.openwrt.org/_media/toh/tp-l … nd-v16.jpg
2. There is all GND surface around the signal trace, so take the nearest spot.
3. I think to have read about ranges up to about 20 db with parabolic dishes. But you never know how reliable these measurements have been.
4. Higher db just means to focus on a smaller area. So usually, the higher, the better. The only problem you may encounter would be that if you operate a client in short distance and within the focus of the host, then the signal levels would be amplified out of range, so that strong parts will be cut off.
5. Give it a try.
6. The biquad is the better choice, as it is already focusing into one direction.

You can use this one 
http://www.aliexpress.com/store/product … 68978.html
Hope you like it .