This sounds like the PVRC mount. It was written up in an old copy of QST.
You might drop your question off on the PVRC reflector. firstname.lastname@example.org
> Someone mentioned that the Hy-Gain Boom-to-Mast Clamp was configured
> to allow rotating the antenna to the vertical position, thus enabling
> one to get to the elements easily. My 402BA manual makes no mention
> of this feature. Is this only on some Hy-Gain antennas or is mine too
> old to qualify ?? How does it work ??
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