David, You can greatly improve reception on your YB-400 by using an MFJ 1020
Preselector. The MFJ 1020 comes with a short whip, don't use it. Attach 20' of
speaker wire onto the rear "antenna input" & drape the wire around a window in
any convenient fashion. Run a short jumper coax from the preselector to the
antenna input. There are 3 knobs, a gain, freq. band setting and a fine tune.
Set the freq. knob to the Band you are tuned to. Set the gain on the low end.
Now slowly adjust the "tune" knob for best signal (when you hit the sweet spot
you will know it). Lastly, adjust the gain until the S-Meter tickles the top
end. Keep the S-Meter from sticking all the way to the top. Power can be had
from a 9 volt battery. You get a good - preselected signal. In effect you are
making a tuneable active antenna. 73 John T. Wagner, Ohio