I thought I'd ask you experts if there's anything that can be done to
improve the reception. I understand the power cord is used as the
antenna. I've tried stringing-up an extension cord to the power cord,
with no improved reception. Could I open it up and attach an external
antenna? If so, how would I do this? Any ideas, or experience with this
particular problem?

In radios of this sort that I've seen, the tuner input circuit is
usually coupled to the AC powerline in one of two ways. Sometimes,
there's a small-value (picofarads or nanofarads) high-voltage
capacitor between the tuner input and one side of the power line. In
other cases, a wire from the tuner input is wrapped around one of the
power-line wires several times (I suspect it's serving as a gimmick
capacitor of a few pF).

If you can identify the way in which this coupling occurs, you can
probably disconnect the tuner input from the line, and bring it out to
a separate jack (pin or banana) of some sort. Then, try hooking a few
feet of wire to this jack, and see if you can get a stronger signal.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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