Richard, an open 1/4 in parallel with the feed point would do the trick.
Your shorted quarter will not be seen at Fo.
A shorted 1/2 wave would.

"Richard Harrison" wrote in message
...
1/4-wave short-circuit stubs. Impedance should be high for 99 Mhz and
lower for other frequencies. For a folded dipole, you might try to use
one, 1/4-wave short-circuit stub and locate it in the middle of the side
of the dipole opposite the feedpoint. This can all be made of 300-ohm TV
twinlead if desired.