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HB9ABX > TECH 27.07.04 18:13l 30 Lines 951 Bytes #999 (365) @ WW
BID : I1IQ8WHB9EAS
Read: DH6JL GUEST
Subj: current balun construcion
Path: DB0FHN<DB0RGB<DB0IGL<DB0FSG<OE7XLR<OE9XPI<HB9EAS
Sent: 040727/1610z @:HB9EAS.CHE.EU [Basel JN37TM] DP6.00 $:I1IQ8WHB9EAS
From: HB9ABX @ HB9EAS.CHE.EU (Felix)
To: TECH @ WW
Current balun / Current choke
-------------------------------------
HB9ABX update 22.Jul.04
This is a 50 Ohm 1:1 balun and serves perfectly to feed a symmetric antenna with a coax,
or to be inserted into a coax to prevent feedline radiation.
Insertion point is just at the antenna feed point
Broadband current balun 1,8-30 MHz
Ferrite ring FT114-43 with RG174 (ok for 100W)
with each side 5 turns (instead of picture)
(better is teflon coax RG316)
or
bigger ring FT24-43 with RG58 for 1 KW
(better is teflon coax RG142)
This type of balun is more efficient than the W2DU design,
where a number of ferrite rings is pushed over the coax cable.
It is also the better choice than winding the coax cable in a loop of several turns.
the coiling technique is important!
The picture not visible here is available at:
http://home.datacomm.ch/hb9abx/loop-choke-e.htm
best 73s
Felix HB9ABX
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