In a message dated 19/06/2009 20:01:53 GMT Daylight Time,
inverted L fed with coax (Tom Williams)
A week ago I removed the UNUN and replaced it with a simple shunt coil. My
SWR is now 1.2:1 at the base and 1:1 back in the shack on 1830 kHz. It was
nice to load the amplifer normally and get 1 kW output with only 3 W
reflected! The 2:1 SWR bandwidth in the shack is 60 kHz.
I use exactly the same method for feeding my inverted L ( 66ft vertical
66ft horizontal ) with 140 1/4 wave radials. A shunt coil of approximately
the same dimensions as yours, I have never felt the need for an UNUN feed.
By tapping the coil it's easy to find the "sweet spot" for 1:1 SWR and once
matched, works really well ( I have over 267 countries on 160 metres ).
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