4 ms·
In college I built something almost identical to this from a 40oz can of yams, and got a connection to a truck stop wifi a little over a mile away (we had direc
by pbnjay 14y ago
In college I built something almost identical to this from a 40oz can of yams, and got a connection to a truck stop wifi a little over a mile away (we had direct line of sight). It actually work pretty well for like 6 months till the weather turned less optimal.
- gonzo 14y agodepending on where you were, the truck stop could have been reached with an ordinary 2.2dBi dipole. Free space loss = 32.4 + 20xLog F(MHz) + 20xLog R(Km) At 2.4 Ghz, this formula is: 100+20xLog R(Km) one mile = 1.61km, so your free space path loss was around 100dB. Let's say the truck stop had about the same radio as you, maybe 17-18dBm transmit power (50-62mW) into a 2.2dBi antenna. Signal leaves the radio at the truck stop at 17dBm, encounters about .8dB of loss in the coax and connectors, and then is raised 2.2dBi by the very short antenna, for 18.4dBm EIRP. It then encounters 100dB of path loss, arriving at the antenna on your laptop at -81.6dBm, where it is raised 2.2dBi by the dipole in your laptop, and then encounters perhaps another 0.8dBm of losses in the coax and connectors. The net result: the radio sees -80.2dBm, which is more than enough signal to decode 11Mbps CCK (802.11b @ 11Mbps) or 12Mbps OFDM (802.11g). So, what you did was unremarkable, though probably fun.