OCF: Proprer type of balun (transformer)
On Mon, 15 Feb 2010 06:34:40 -0800 (PST), ve2pid
wrote:
I have a question about OCF dipoles; it refers to the choice of the
type of balun transformer (voltage or current) to be used with that
type of antenna:
What is most important is the choking action which then demands a
current BalUn. As the transmission line falls away from an unbalanced
dipole, it also upsets they symettry further by its presence. This
further demands you choke it at quarter wave intervals away from the
feed point. As the OCF Dipole is meant to be multiband, this then
demands a number of such quarterwave-away chokes. My solution has
been to place a bead every foot along the entire drop.
The next trick is with the BalUn ratio. Few describe that accurately,
defend their choice, or even pretend to know. Further, the degree of
off-centeredness is another wild guess that none suggest makes a
difference.
73's
Richard Clark, KB7QHC
|