This L - Match ATU has proved very effective for matching a high impedence long wire and is ok up to the 300W power level ( I have not used it with any more power than this ). The coil was wound on a spent industrial ceramic cartridge fuse, however plastic waste pipe is also suitable. The HF end of the coil has its windings widely spaced to reduce interwinding capacitance. A simple SWR bridge is included to allow easy adjustment of the L Match. I use this L match with 40m of wire and my 20/80m transceiver when on holiday, good results have been had. The circuit is very simple and construction should not present any problems. For the meter, an old VU meter is used with the scale redrawn, any meter with an FSD of 100uA - 500uA will be ok. The switch for extra capacitance puts a 180pF capacitor in parallel with VC1, this is in case I can't get enough wire up in the air so have to use an elecrically short half wave wire on 80m.
Barry Zarucki M0DGQ
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