edwin wrote:
... but like to try a full wave antenna 2x 5.17 meters, ...

For maximum gain, you would need an Extended Double Zepp
dipole. It would be approximately 13 meters long fed with
a matching section of 450 ohm ladder-line that is approximately
1.8 meters long. Install ten turns of coax where the coax
connects to the ladder-line. The above lengths would need to
be adjusted, plus or minus, for lowest SWR.

If you really want a full wave antenna, feed it with
approximately 2.5 meters of 450 ohm ladder-line with
ten turns of coax at the coax/ladder-line junction.
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73, Cecil http://www.qsl.net/w5dxp