best antenna to go through walls?

Wireless doesn't work well under water. For that matter, neither does your laptop.

Lots to chose from. Hint: The bigger and uglier the antenna, the better they work.

What's inside the walls? If it's aluminium foil backed insulation or lath and plaster, give up now. As I see it from your PDF, you're going through 4 walls. That's a problem even with more conventional drywall construction. Offhand, I don't think you have a chance.

A range extender would need to have a good view of both ends of the path. I don't see a common area, except perhaps outside the building through windows.

If the building is on a common AC power line, perhaps power line networking might be more useful.

Dunno. Without a fair idea of how much attenuation you're dealing with due to the 4 walls, it's impossible to determine the optimum antenna. Also, you making an assumption that a better antenna will need to be only at the WRT54G end. That will help, but you can also dramatically improve things by adding an antenna to your unspecified model laptop.

Good enough. The problem is that I can't calculate how much gain is required without knowing how much the walls attenuate the signal. Perhaps you can borrow an antenna and try it? Just about anything with gain will do for testing. If you can get any kind of signal with Netstumbler or Kismet, you have a chance.

Hell no. The reflections will cause problems inside the building.

For good reason. A 12dBi omni will be about 6+ feet long. Add 3 more dB of gain and the length doubles.

Actually, the small distance probably doesn't make much difference in path loss.

Lay off the repeaters, range extenders, boosters, power amps, etc. They work in some situations but not one where there's probably very little signal to work with. Yes, you need special low loss cable. If you're going 25ft or more across the room, you'll need about 30ft of LMR-400 coax with N connectors and an N to RP-TNC pigtail adapter.

Perhaps you might find it easier to move the WRT54G and use CAT5 for the data extension? Before you fork out for the coax, try it from the existing location as I don't think moving the antenna is going to do much.

Get the Netgear powerline networking adapters. Use the 84 Mbps versions. There is a set of two that they sell where one plugs in to your router and the wall socket in your apt. The matching unit has built in wifi and plugs in to any other wall socket on the electrical. Should work all over you apts.

Take this second unit out to the pool and plug into a socket nearby and make an AP at the pool.

Be sure to use security on the powerline system (read the instructions) and also on your new plug in AP.

Steve

Try to explain that to the XYL.

DTC hath wroth:

I'm not married, so it's not a problem. However, the current ladyfriend has already balked at me installing an antenna on her car for GMRS.

The secret to installing a big ugly antenna on the house rooftop is to start small. Every few weeks, just add a bit more to the installation. A taller pipe, a bigger reflector, additional elements, and phased arrays can always be added slowly. If they can't be expanded, then perhaps a similar but larger antenna. I would think the antenna manufacturers would get the clue and sell expandable (inflatable?) antennas. Anyway, starting small, and growing slowly works quite well and avoids the instantaneous adverse shock reaction of a big ugly antenna (that works well).

Unfortunately, I may need to downsize my antenna farm and racks full of nifty (junk) electronics. Most of the women that have seem my house ask something like "You live like this?" which implies that some changes are going to be required. In 1975, the county planning department hinted that my house might be designated a local eyesore after I did some remuddling.