> Since you mention a dipole, there's an example here (page 11)
>=20
> http://www.rfm.com/corp/appdata/antenna.pdf  (106kB)
>=20
> of a PCB trace 'folded dipole' for 434MHz. In that form it's too
> long for the case I'd like to use, which is unfortunate because the
> author says it has very good performance. Perhaps it can be re-
> arranged to be wider and shorter to suit a small case. For example
> can the top half be rotated through 180 to be next to the lower
> half and still perform ? Where he notes 'feedpoint', does he mean
> that the signal is connected to just the lower trace end ? I'm
guessing
> he does otherwise the two traces would be shown joined

For an aerial like that it should really be fed from a balanced source.
Think in terms of the old style VHF TV aerials with the ribbon cable
coming down to the set. In that case the ribbon cable is carrying a
balanced signal, about the earth connection, and goes into a balun
inside the tuner to convert it to an unbalanced signal, i.e. one side is
grounded. So for the traces pictured there the feed point really
requires a balun that the transmitter unit feeds.

A suitable balun is normally a few turns of wire on a ferrite core. The
gauge of wire and core type both affect the characteristics of the
balun. However it is worth getting down to your local library and having
a look at an ARRL or RSGB handbook to see what the amateur radio guys do
at 70cm for baluns, as there are tricks that can be done with coax or
PCB traces to achieve similar results.
--=20
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