I don't understand why you are imposing this requirement. If the antenna is
designed to provide the correct impedance for the cable, then you shouldn't
care about the length. If it isn't matched correctly, then making it an odd
number of quarter wavelengths isn't going to help much, as far as I can
see, because all that will do is allow two matched conditions (one where
the antenna presents Zo(cable characteristic impedance), and the other
where Zo is the geometric mean of the antenna's impedance and the
transmitter's impedance.

Sean

At 07:58 AM 3/26/01 +0200, Kent Johansen wrote:
>One note of caution: beware of the stand wave ratio. (SWR). A
>quarter of a wavelength is 17 cm. The antenna cable should be an
>odd number of quarter wavelengths, corrected for the cable factor.
>It is very hard to measure SWR on 433MHz (If you don't have a
>Bird Wattmeter). The best way is to guess and correct. But a
>wrong SWR will be able to completely eat your signal.

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