Thursday, February 19, 2009

Add an external wifi antenna Panasonic CF-R1 (Or any other laptop)

On my recent trip to Japan, I picked up a Panasonic Toughbook (or Let's note) CF-R1 for about 10,000 Yen, equivalent to $110 or so at the time. It is a beautiful 10" sub-note that sports a Pentium 3-M 800Mhz ULV Processsor and 256MB of RAM. The CPU is the new Tualatin core, so the performance should better than EEEPC's 600Mhz Celeron. The RAM is a bit shy, which means I'll be running a stripped down version of XP, or a light Linux distro.


Panasonic CF-R1

When I bought it, the laptop had very little wear on battery life, and only a bit of discolouration on its plastic palm rest. The biggest downer though, was the lack of a Wifi card. Understandable considering this is from 2002. The laptop did however, come with a mini-PCI slot, so I got a spare wifi card and decided to add this capability.

For those who do not have spare wifi cards laying around, they're very cheap. I found one on ebay for less than $6 shipped Here. I went with an old Intel 2100 since it had very good driver support on linux.

The next problem was, that the laptop had no built in antennas like most recent laptops. You can buy panasonic OEM ones that go on the LCD, but that just wouldn't be very ghetto. So just to be hardcore and ghetto, I decided to add an external antenna and an internal auxilary antenna.

A side lesson on antenna connectors: If you already know this, skip this section. Most antennas for wifi will have one of two connectors: RP-SMA, and u.fl. all internal laptop wifi cards I've seen use the u.fl connector, while most desktop cards and routers use the RP-SMA connector.



u.fl internal antenna

For the internal antenna, you can get one reasonably cheap on ebay Here but if you have a broken laptop, you can salvage it from there; the antenna itself is usually somewhere behind/around the LCD, and there is a pig tail cable that leads to your wifi card. it doesn't matter what shape it is, it should be small enough to just jam into free space available on your target laptop.


RP-SMA Antenna and u.fl to RP-SMA cable

Now the real fun, the external antenna. You can get these everywhere, ebay, old routers, desktip wifi cards, etc. As long as they're good for 2.4 Ghz, you're ok. I ripped one out of an old router, which luckily also had the RP-SMA connector I needed. Since most external antennas use RP-SMA, I will need a u.fl to RP-SMA cable, and make an RP-SMA port on my laptop. For those of you who can't salvage these parts, they are also very cheaply available. Get an RP-SMA antenna here, and a u.fl to RP-SMA cable here. Another option is to just get an external antenna that has an u.fl cable comming out of it, but if you do this, you can't take the antenna off.

Next, I had to find a place to mount the RP-SMA connector. Lucky for me, the modem port (RJ-11 port) was the perfect size, located right next to the mini-PCI, and I don't feel bad for ripping it out. Also, since it's recessed, the connector doesn't even jut out too much (some guys who modded their EEEPC with the RP-SMA had it comming out of a drilled hole, and it stuck out of the case a lot). So unless you have an odd attachment to your modem port, it is the perfect place for your new RP-SMA connector.

Putting the connector in place was simple as ripping out the old RJ-11 jack and epoxying the connector in to place. Be careful not to get epoxy on sensitive places since its dielectric properties may affect sensitive electronics. I used 5 minute epoxy, and it worked out perfectly. Just file/sand the plastic around the connector as needed to accommodate your antenna.

The result was very good. With only the internal antenna, I was picking up about 6 AP's at my university, but with the external antenna, I was able to pick up 31! The signal strength also increased from around -60dB to -30dB.


The RP-SMA connector in where the modem port used to be


The black wire goes to the internal antenna, the light brown wire loops and goes to the RP-SMA connector


CF-R1 with the external antenna attached

Update: Some people have questioned the need for such mods when internal antennas have pretty good gains. True for most laptops, but Toughbooks uses some magnesium alloy instead of plastic for the LCD back bezel (The front bezel and side chrome parts are plastic. So when I installed the internal antennas behind the LCD, the signal was quite poor. Most laptops have plastic bezels and alloy frame, which makes RF waves propagate easier through the bezel. The OEM antennas sold by Panasonic is designed to mount where the chrome plastic side piece is, since the plastic piece won't block the signal as much as the alloy back bezel.

4 comments:

  1. mine is prettier, and it doesn't get in the way of your hands =]

    http://tinypic.com/r/2rggvvo/3

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  2. This was my inspiration to add an antenna inside the ethernet jack of the EEE PC 1000HA! Thanks :)
    http://streamingfreebies.com/2010/03/adding-recessed-wifi-antenna-eee-1000ha/

    ReplyDelete