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Old September 16th 07, 11:08 AM posted to alt.engineering.electrical,rec.radio.amateur.antenna,uk.radio.amateur
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First recorded activity by RadioBanter: Sep 2007
Posts: 7
Default Complete Bollox? Or...Was: what makes it a balun????

"Brian Reay" wrote in message
...
"Malkavian" wrote in message
...
Hi peeps. In the last hf ssb competition a group of us put up some
antennas and a 2e0 took a length of wire, wrapped it around a bucket
seven times, removed the bucket, taped to coaxe up then put it inline
with the yagi. Now t may seem dim but to me this doesn't fit into my
cinceptions of a balun, not even one to one balun. So how was what the
2e0 made a balun?


If you aren't familiar with this type of balun and think of baluns as all
being transformer like, I can understand your question. Basically a choke
balun provides a line isolation function by virtue of the fact that any
stray current on the outside of the coax outer has no counter current in
the coax, thus it sees the coil as an inductor. Conversely, the (wanted)
signal currents (on the outside of the inner and inside of the outer)
cancel out the magnetic fields they form in the coil and thus don't see it
as an inductor.


You seem to be remarkably ignorant about the containment of the fields
within the coaxial cable, OM. Neither within the configuration of the coil
nor in straight line sections of coax do the wanted signals contribute to
any
external fields (save, perhaps, in the case of leaky feeders).

The wanted currents just do not form any magnetic fields in the coil to be
cancelled out!

Such ignorance would be an absolute disgrace if it was expressed by, say,
one
charged with the training of all candidates for Radio Hammery in Britland!