Is 50% download speed on a wireless G network normal?

Sounds unsurprising. There are lots of things that can affect the performance of the wifi AP.

Including:

• Interference
• Other nearby Wifi AP's & devices on the same channel (neighbours?)
• Walls
• Metal objects
• Distance of device to AP
• Antenna gain
• Transmit power.

In DDWRT there is a menu option that allows you to "scan" for other devices. Use that to determine the presence of other Wifi routers that the AP is seeing. Choose the quietest channel and retest.

You're getting plenty of signal too so it's most likely some sort of interference.

By the way, channels above 11 are not commonly used. And I once tried channel 14 but found it was limited to something like 5 or 10MHz of bandwidth and did find documentation on this but haven't located that yet. So do try other channels.

I've googled for "maximum 802.11g speed" and found several threads, including superuser reporting that a G network will max at about 22-25Mb/s.

Also Wikipedia about 802.11g: "It operates at a maximum physical layer bit rate of 54 Mbit/s exclusive of forward error correction codes, or about 22 Mbit/s average throughput."

So it is a normal speed, I got it a bit better (max about 22,5Mb/s) by enabling afterburner and frame burst features (thanks Blisk!). Guess its time to get me a N access point.