Adding an external antenna to a NetGear MA401
The NetGear card external antenna mod is pretty easy and I was surprised that this card hadn't already been documented on the Internet. Perhaps the greatest virtue of this card is just how easily it comes apart! In fact, shake it hard and it will almost come apart for you (I dropped mine once and that gave me an insight into just how easily the card dismantles - or just how flimsy it is, depending on your point of view!)
This modification is in two parts, case disassembly and the details on the PCB modification. You might also want to take a look at the modification to an SMC2632 since it is pretty much identical:-
Firstly remove the top of the antenna lid by inserting a sharp knife between the plastic, it's not glued, just clipped into place
You can then run a finger nail around the rest of the plastic, lift it up as shown
There is a plastic tab that slides underneath the metal shroud, just ease the plastic lid away
Even the metal case comes apart with ease, once again, using a sharp knife, start about 5mm in from either end where there are cutouts in the plastic and insert it from the bottom, the case clips together and if you click on the photo, you'll see the two cutouts. Work the knife carefully along the case and repeat on the other side
Lift the back of the case and slide towards the connector end to clear the two retaining tabs and the top of the case then comes away
The connector end is stuck down to the lower half of the case with a very low bond adhesive so just lift the PCB clear of the lower half of the case
In the following picture, I have reassembled the top half of the case and plastic antenna housing so that the drilling hole can be marked in the right position. Simply mark with a pin or small drill bit by making an impression through the centre hole of the SMA socket
Top side photo (click for larger picture)
Bottom side photo (click for larger picture)
Close up of PCB modification area
Add two surface mount 150pF capacitors to the areas marked, I chose Farnell Electronics (http://www.farnell.co.uk) part number 301-9238. These capacitors are small! Did I mention small? 1mm x 0.5mm and a 1mm soldering iron bit dwarfs the component.
You will also need a PCB SMA socket, RS Components (http://www.rs-components.com), part number 111-712
Click the picture for a larger view of the modifications to make.
The capacitors are NOT large, my soldering has always been good but this was the first time I have tried soldering 1mm surface mount components. Tin the pad and using very very fine tweezers, move the capacitor into the solder. The following picture gives an idea of the scale!
Remove the inductor and solder the two additional capacitors. I found the hardest task to be determining if the components were actually on the board properly. It's very very difficult to do so by naked eye, my "Handi grips" with magnifying glass didn't help much and even an 8x lupe only helped to a point. The following picture was done using a flatbed scanner, which actually helps quite a lot. (After this picture, I resoldered the lower capacitor because I didn't like the look of it.)
Cut the lead of the SMA connector to 1.5mm or slightly less, any longer and the case won't snap together! Solder the SMA connector from the underside, the following picture makes it look like the connector was soldered from the top, it wasn't - it's simply that the solder has flowed through the through plated PCB.
Drill a suitably sized hole in the antenna lid. You will probably find it easier to remove the plastic film window for the LED and simply cut a small hole for the connector with a knife
Re-assembly is simple. Arrange the parts as follows and just snap together! (If you try to snap the two metal halves together first and then add the antenna lid, you'll find that you don't have enough room to tilt the lid to get the plastic tab underneath the metal lid - unless you've made a very large hole for the connector!)
The finished card
Although as yet untested, reference to the following Intersil document http://www.intersil.com/data/fn/fn4/fn4856/fn4856.pdf shows that CR31 controls the transmit power which is by default at 0xF0. Setting this to 0x80 (these values are in hex, just use 80 in the software!) should set the power to 100mW instead of the default 30mW.
The tool to do this is at http://www.intersil.com/design/prism/software-o/PrismTestUtil322.exe.
If you do this and it works please let me know so that I can update the information here.