How far will this setup go?

Do these two WRT54Gv2 routers talk to each other? Unless you've installed replacement firmware that does transparent bridging, they will not talk to each other.

You won't get very far. Yagi's suck because the length necessary to obtain gain that is comparable to a 24dBi dish or 19dBi panel is rather long. The biggest yagi I could find was 16dBi and that was really two 13dBi yagis glued together. My guess(tm) is the length necessary for a 24dBi 2.4GHz yagi would be about 20ft long. Not very practical. My guess is that your customers two unspecied make and model Yagi's are no more than 15dBi gain.

The WRT54G puts out about +15dBm at the coax connector. Since you didn't bother to specify a length of coax cable, I'll assign 25ft of LMR-400 (7dB/100ft) and fairly short pigtail. Total loss for the coax cable, connectors, and pigtail are about 3.5dB. I'll assume a symmetrical system at both end.

All we need to know is what speed you expect, which will determine the receiver sensitivity. Using numbers from a DI-624 (close enough). * 54Mbps OFDM, 10% PER, -68dBm) * 48Mbps OFDM, 10% PER, -68dBm) * 36Mbps OFDM, 10% PER, -75dBm) * 24Mbps OFDM, 10% PER, -79dBm) * 18Mbps OFDM, 10% PER, -82dBm) * 12Mbps OFDM, 10% PER, -84dBm) * 11Mbps CCK, 8% PER, -82dBm) * 9Mbps OFDM, 10% PER, -87dBm) * 6Mbps OFDM, 10% PER, -88dBm) * 5.5Mbps CCK, 8% PER, -85dBm) * 2Mbps QPSK, 8% PER, -86dBm) * 1Mbps BPSK, 8% PER, -89dBm) I can now arbitrarily decide that you'll want to run 12Mbits/sec which will yield a thruput of about 6Mbits/sec. That gives a receive sensitivity of -84dBm.

Distance = ??????? TX power = +15dBm RX sens = -84dBm (at 12Mbits/sec OFDM) TX ant gain = 15dBi RX ant gain = 15dBi TX coax loss = 3.5dB RX coax loss = 3.5dB Fade Margin = 20dB (minimum)

Going to the online calculator at:

enter various values for the distance until I get a 20dB fade margin (SOM). That yields 0.75 miles. Yuck. Actually, I think that's optimistic. If you go slower, you can go farther.