Kevin Nathan wrote:
>I would then go out an electrical quarter wave calculated for the particular
>type of line I was using and would tie the two sides together. I would then
>tie the far end together so that the short section of twin lead tied together
>at either end acted as a voltage cap.
>
>I have tried to find descriptions of this antenna on the internet without much
>success. I find the antenna but they don't mention where to tie the ends
>together and one description actually says that if you put it up as an
>inverted L, you actually need to make it shorter but it doesn't give any idea
>of how much shorter it ought to be.
>
>Kevin,
>
A version of the folded back marconic top exists in a US Military
handbook but with only the far end tied together. The total length of
the flat top (with one end of the two wires connected and a single
connection to the vertical downlead on the other end is 1/8 wave because
the total distance traveled is a 1/4 wave on the top section alone. 450
ohm ladder line is actually better than twin lead as the top section
since the voltages are quite high at the open ended portion. The
military version uses open wire line with spacers but there is no
reason, depending on power levels why ladder line would not work. This
portion of the antena is d3eisng to cancel radiation from the flat top
concentrate more radiation on the vertical portion. This will actually
benifit your lower angle take off for working DX on topband and 80
meters,depending on the design frequency.
Good Luck
Herb Schoenbohm, KV4FZ
>
>
>
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