I recently acquired one of these cheap 2m handhelds from China, an
FDC-150 I think. It's great for the price (£30) apart from a problem
with QRM.

I use the radio with a 3 element beam from SOTA activations from hill
tops. It varies from location to location, but I often get strong
intermodulation effects (caused by pagers I think). I suspect the
radio, being wide band 136-174MHz, has insufficient filtering to
reject these strong signals.

The intermod is a real problem, as I am often unable to hear stations,
or only get half of what they are saying before they are wiped out. I
was wondering about building a 2m bandpass filter like the one at
http://www.arrl.org/tis/info/pdf/0005054.pdf

Does this look like a good bet?
Also any ideas where I can get the semi-rigid coax (UT-141 or RG-402)
in the UK?