Here's the situation: Sometime last year, we got a scope after some
begging by a tech. He then said that the cell tower out back (somewhere
between 50-100 feet away) was causing interference. He quit, and the
other 'tech' working in the shop was fired. Now that I'm in there, the
'boss' wants the scope out and working, but all I hear is, "Oh, that
doesn't work" from a couple of people.

Now, I have very little experience with scopes, and think that possibly
this is a grounding problem, or of course, there is a need for
shielding, or knocking down the tower itself. The scope is used, and
probably around 20 years old, and looks like this:
http://dustbunny.physics.indiana.edu...pes/t475_c.gif
, the Tektronix 475.

Any suggestions on shielding the interference, or testing to make sure
of the existence of local interference?