Homemade Laptop Wi-Fi Amplifier Review Amplifying your laptop Wi-Fi
I have always been frustrated with the performance of my laptop Wi-Fi. I tried many solutions to improve the signal from far away routers, but few of these worked. I'll cover a solution that I came up with that finally did yield some results for me. Most laptops nowadays have a mini PCI Wi-Fi card hooked to an antenna which is located inside a screen plastic cover on the laptop. I was browsing eBay recently and noticed that there were some Wi-Fi amplifiers available that promoted themselves as improving the reception of the signal. Sadly most of those amplifiers are designed to be hooked to a PCMCIA type card or a router! None of them seemed to be specifically made for a mini PCI card. I decided to buy a Wi-Fi amplifier and hook it to my laptop. I have an ASUS A2H laptop with a Dell 1470 a/b/g Wi-Fi mini PCI card inside, I bought the card for $20 off of eBay. I bought the amplifier for $118, it is a 500 mw bi-directional amplifier called "turbo tenna", the amplifier was shipped from Hong Kong and I received it shortly after ordering on eBay. 
The Wi-Fi Amplifier, "Turbo-Tenna", purchased from eBay (view large image)
The Design:
The first problem I faced with my Wi-Fi card were the connectors, they are so small and very difficult to connect to a plug, buying a special connector for the card would have cost me another $15 plus shipping, so I decided to solder the cable directly to the card. One of the best features of the Dell 1470 is that you can select the antenna plug you would like to use -- main or aux, so I selected the main and I soldered the cable to it.
The second problem was power supply! As usual, if you have a mother board the best power supply you can get is from a USB port. I needed 6v, and the USB was giving me 5v -- close enough! 
Power supply from USB (view large image)
The third problem was hooking the card to the amplifier. I had 2 options, I could either take off the circuit of the amplifier and find a place for it in the laptop, which is a nice idea, or I can find a way to hook it externally. Though I wanted to put the amplifier inside the laptop, I decided not to do that for the following reasons:
- I wanted more liberty hooking any antenna I wanted to the amplifier.
- It is very difficult to find a place for the amplifier inside the laptop without affecting other components.
- Heat issues! Those amplifiers produce heat and they are not supplied with an adequate heat dispenser.
- The amplifier was expensive ($118) and I wanted to preserve it.
I decided to hook the amplifier through the VGA monitor out port! Why? First reason, the port is strong and can hold the weight of the amplifier, plus it comes with screw holes. 
The VGA plug and Wi-Fi antenna cable (view large image)
Secondly, the VGA port comes with a few pins that are unassigned, sometimes they are soldered to the ground, and in some cases they are simply soldered to nothing. So it was a matter of testing those certain pins to see if they were connected to anything else on the mother board. After testing the pins I found out that pins # 9 and #11 were free, so I used #9 for the power supply and #11 for the antenna cable from the Wi-Fi card. I used the ground for the VGA for as a common ground for the power and antenna cable.
Wires in the VGA plug (view large image)
Wires to the VGA on board (view large image)
One thing I should mention, I am a switch freak, the more knobs on the machine the happier I am. I placed a switch inside the laptop that switches all the wirings between "normal" and "amplifier on". I have tried many Wi-Fi antennas, the "spider" antenna is effective but doesn't offer high gain, while the so called "russian" antenna gives you more gain, but it is a bit bulky. I have used the russian style antenna in this experiment.
Spider and Russian antenna examples (view large image)
Amplifier hooked to the laptop (view large image)
Testing:
Using "Network stumbler" as a testing software, here are the comparsions between normal and amplifier on:
Normal: The signal is weak and intermittent, it doesn't even reach -90 dBm, which is very weak. If I get lucky, the connection is usually 1Mbps with signal strength 0-1% and sometimes no connectivity (I guess you understand my frustration). Very few signals are detected, and sometimes nothing at all. 
Weak signal
Amplifier ON: A dramatic increase in signal strength! More than -80dBm, and the speed of the connection is 24Mbps with signal strength 34% as compared to the same connection at 1% previously tested. You can also see more Wi-Fi connections around you, though of course they're all password protected. 
Stronger signal 
Signal difference chart (view large image)
Pros:
- You are never disconnected wherever you go!
- Very light and attractively built, adds style and performance to your laptop (it is fun to see other poeple looking at it and wondering what the hell is hooked to the VGA port!)
- Very mobile and removable modification.
Cons: - Radiation, I believe this thing produces the same amount of radiation that a cell phone produces, so try not keep it on too much, especially when you don't need it.
- Power consumption! It drains your laptop battery.
- Interferes with the back of the display, unless the VGA port is on the side.
- Requires an internal modification to be used on the VGA port, the VGA port might cause probems if hooked to a monitor that uses the unassigned pins (very small likelyhood though, the switch I made saves the situation).
- Can't use VGA port and Wi-Fi amplifier in the same time.
- Don't do such modifications if you don't have the knowledge and experience...and guts.
- Every country has regulations, be careful not to break the rules when hooking such a powerful thing to a Wi-Fi card.
- Amplifier company says: "Don't exceed 50 mW to the input power of the pen booster", so if your card has higher capacity then it might damage the amplifier!
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