On Sep 3, 7:44*am, Cecil Moore wrote:
wrote:
By the way, I have seen so many articles about baluns written by other
hams and they tend to repeat the same mistakes and assumptions. Most
hams do not understand how a balun works.

Your following statement puts you in that category.

Inserting a balun does not "choke" the current in the shield, it
merely shifts the output phases so that the current (voltage) is
directed towards the dipole at all times (see my other post in this
thread).

This applies to a W2DU balun. Why would you want
differential current fields to be introduced into
the #77 ferrite beads? Their entire purpose is to
provide a large choking impedance and dissipate
common-mode power.
--
73, Cecil *http://www.w5dxp.com

OK, next time I specify an EMC filter for a switching power supply, I
will ensure that the CM choke impedance matches the impedances of the
network and the loads so that I can most efficiently conduct RFI from
the source to the power line, from common mode at the load to
unbalanced load of the power line source. This will ensure maximum
interference is imparted on the phase conductor. In fact, I think I
will change my nomenclature by refering to the "choke" as a
"balun" (they are one and the same; the source doesn't know the
difference!) and promptly fail my next FCC submittal. Then I will be
invited to retire and of course I will have much more time to be re-
educated on rec.radio.amareur.antenna.