Collins Radio did just this on a family of HF antennas in the fifities and
sixties. The two booms meet at a point.
Collins still has some in service at their Cedar Rapids HF Station.
I work at Collins so I see them almost every day.
de na0ia
At 04:12 PM 3/19/02 , jljarvis wrote:
>
>Folks,
>
>I've lost track of who suggested this...but I would like
>to hear from anyone who has modelled or actually installed
>two log periodic arrays, stacked, but NOT parallel.
>
>That is, by tilting the leading edge downward, on the UPPER
>lpda, and the leading edge of the LOWER lpda UPWARD, it should be
>possible with an 18' boom lpda to have the first 10m elements
>spaced by 16', and the last 20m elements spaced by 32'.
>
>I haven't bothered to finesse the geometry, but it would appear
>possible to space and tilt such that you obtain maximum gain
>from the stack, when driven in phase.
>
>Anyone actually DONE this? W1CX relates seeing a pair of KLM
>7-30 lpda's like this in Panama, while transiting the canal.
>For purposes of discussion, assume there will be no mechanical
>mounting issues.
>
>
>Jim Jarvis, N2EA
>
>
>
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