Dave, I have seen you get some good information and some bad
information. The 1/4 wave will give you better results over the short
rubber duck.
There will be not much difference in the pattern between the original
antenna and the 1/4 wave. There will be an improvement in signal level
by about 10 dB. One poster said that you were in trouble because your
antenna was vertical. I am willing to bet you can turn your head and
look upward with the scanner turning upward as well.

Your radio is designed for a 50 Ohm antenna so half or more of the
information given by "Reg Edwards" is bogus as well. I don't think he
tried to mislead you, but may not have experience in real life experiments.
The case of the radio is important only in how it capacitively couples
with your hand or body.
A short vertical has an impedance far below a normal quarter wave. That
means your idea matches better to your radio.
As a sort of ground wire, a 1/4 wavelength long counterpoise, (as
someone said a rat tail) will also help.



Dave wrote:
Richard Clark wrote:


The standard rubber duck and a quarterwave are going to have the same
failings: they both have the same response curve in space. Basically
they both are designed to work with transmitters located at right
angles to them. And if you stand in the conventional upright manner
of a biped, then those antennas are going to be vertical with the
favored direction lying along the horizon.


Richard,
Thanks for the advise. However, I thought 1/4 wave antennas were more
isotropic than 'most' other antennas... (see link below)

http://www.astrosurf.com/lombry/Radio/dipole-height.gif

What am I missing?

Basically, all I'm trying to do is increase the sensitivity of my
handheld scanner for the 2m range.

Thanks,
Dave