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Baluns?
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September 4th 08, 03:51 AM posted to rec.radio.amateur.antenna
John Smith
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First recorded activity by RadioBanter: Nov 2006
Posts: 2,915
Common and Differential Modalities
wrote:
Let me put it this way (again very simplifed): How do you explain a
residential 208V power source where you have 120 V from line 1 and
line 2 to ground but 240V with respect to each other. You 240V
household appliances operate this way. Ecept for the fact that the
lines are 120 degrees out of phase phase (insread of 180 because we
use a delta system instead of Y, but this is not that important for
this discussion) this is nearly a BALANCED feed, where lines 1 and 2
degrees out of phase at 60 Hz and the voltage of interest is the
summation of the two lines. Nearly every home in the USA operates this
way. In Europe, 240 V is usually obtained by the voltage difference
between line 1 (240V) and earth (0V). That is an unbalanced feed. You
can insert a 1:1 isolation transformer using the European system at
the input and create the balanced USA system at the output by drawing
+120 and -120 at from the output windings assigning imaginary isolated
earth at centertap. The isolated ground CANNOT conduct tio real ground
if the winding to winding impedance is infinity. Basically, hams' 1:1
baluns do much the same thing: They isolate the real ground as such
and prevent currents from flowing down the input ground shield. On
this ng in a short space I cannot think of a simpler way to express
this although I expect to see many statements (you can't equate 60Hz
to RF!). Yes you can; a transformer operates as a transformer in the
same wayat any frequency providing you design it properly for the
frequency of interest. This subject is not nearly so complicated as
some in this group makes it out to be and the topic certainly does not
rate articles in amateur publications any more than basic application
of ohm's law does.
Yanno, you really deserve richard. Did you ever thing about getting a
place in the "gay bay" together? ROFLOL!
Regards,
JS
--
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the police are supposed to protect us from!
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