I came across a few Proxim RangeLan2 7200 cards the other day. I've hooked one up and tested it out as a poor man's spectrum analyzer. So far so good.
Now, I would like to hack in a very directional antenna so I can use it to try to track a source of RFI. The antenna on these is actually located on a box that is connected to the card via a 4 inch or so cable and an odd connector (looks similar to ethernet dongle connectors I've seen). But inside that box, the antenna connects to a PC board via what looks very much like the antenna connector used on Apple's Airport cards (a little tiny thing, I suspect it may be a fairly standard connector for that size)
First, would a directional antenna work to let me see where the source of the RFI is? I figure I could point, let it scan for a bit, then move and repeat. When I see the RFI appear on the graph, I can then head in that direction and repeat until I narrow down where the source is. Does this sound reasonable?
Second, what kind of antenna would be ideal for this? How directional should I be looking (and what is the correct term called so I know what to look for). I'd think if I get one that has too small of a reception area, then I'd never be able to narrow down the location because even the smallest move would radically change the end pointing spot, so I'd have to be looking almost dead onto the source to pick it up at all. On the other hand, one that is too large a field would never let me narrow it down enough to have any idea where the source is.
Has anyone done this already? If not, any tips, hints, suggestions, or otherwise to point me in the right direction is appreciated.
(ps: I apologize in advance for spelling or other errors, my news client lacks spell check and I'm the type that really needs it)