Weird Wireless Problem with usb rtl8187 adapter

[Rick Bilonick]

I'm using F8 on a Dell Insprion 2200 laptop with a miniwifi card which
works nicely with ndiswrapper. I needed to amplify the wireless signals
(they are weak where my office is) so I borrowed a Realtek 8187 usb
adapter. I won't go through all the details, but the end result is that
the usb adapter with the antenna directly attached works perfectly with
the native rtl8187 drivers (I didn't have to install anything) and
NetworkManager. I can ping and browse the internet and the device pulls
in a stronger signal. However, there is also a signal amplifier that can
be attached. You take off the antenna, attach a short wire connector,
attach the amplifier (noting the appropriate end) and then attach the
antenna to the other end of the amplifier. This also works but ONLY so
long as I DON"T plug in the power supply for the amplifier. As soon as I
plug it in, pinging stops and access to the internet stops. If I unplug
it, everything is fine. I've done this half a dozen times - it's
completely reproducible.

Does anyone have an idea why plugging in the power supply to the
amplifier would stop networking from working? What is also weird is that
if I enable "network" using services (rather than just using
NetworkManager), I can do "iwlist wlan2 scan" and it will detect
available networks - whether the power supply is plugged in or not.

Rick B.