Several months ago, my friend was attempting to attach an external antenna onto a wusb11 v2.6 card. Unknown to him at the time, while soldering on the antenna, he took of a surface mount capacitor. It is number 27 but I cannot find a schematic for this particular card. I have tried going to the FCC site but the schematic for the card is listed as confidential. From looking at schematics of other cards, and looking at the traces on this card, it looks that this capacitor is in series with the antenna and is around 5 to 20 Pico farads. This is what the antenna connector should look like. (Picture from here) The blue arrow points to the capacitor that is missing on my card. The red arrow points to a different antenna pad that also needs one or two capacitors to work. This is my card. The arrows point to the same places as in the previous picture. I should also mention, when we were trying to get the thing working a while ago, we bypassed the capacitor with some solder. It got better signal strength but with lots of noise. Any help would be appreciated. Edit: fixed images
just buy a normal capacitor and solder it into place, get a value around what you think it was. as you said it worked without it so by using trial and error you can find one that works fine.
That is probably what i'l end up doing. I am just hoping that i can find the original value so I dont have to buy more than I need. Il be able to get some capacitors on monday to try out but i'd have to order surface mount capacitors on-line from digikey. Any idea if using non surface mount capacitors would cause a problem?
no using a standard cap wont make any difference, they all do the same thing jus SMD caps are smaller. A normal cap of that capacitance wont be much bigger than the SMD capacitor would be.
I guess I wasnt very clear on that, the reason that i'm worring is because of the high frequency and maby the lengh of the wires could effect something. But your probably right, It wouldn't make a difference.
what might be a problem is if he has already powered it up. without a matched impedance he might of nurfed the controller ic. A 'safe' bet to would be to call up the datasheet for the controller ic, and look at its example circuit, use the values for that.
