G8MNY > TECH 03.12.18 11:30l 39 Lines 1216 Bytes #1 (0) @ WW
BID : 47694_GB7CIP
Subj: Coax Sleeve Balun
Sent: 181203/1019Z @:GB7CIP.#32.GBR.EURO #:47694 [Caterham Surrey GBR]
To : TECH@WW
By G8MNY (Updated Dec 04)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
This type of balun is to be found in most textbooks & many aerial designs. It
is a 1:1 balun & does not alter the impedance.
Balun is made from ¬ wave lengths of scrap coax (longer needed to cover the
fatter outer) braid or pipe over the top of the feeder. It is electrically
connected to the coax braid 1/4 wave from the balanced feeder connections.
BÄÄÄ) UNBALANCED FEEDER
This works by hiding the unbalanced outer aerial connections from the outside
world so it can't radiate.
In practice I recommend heatshrink sleeving & heat glue it used to seal the add
Common mode Z is only high at the resonant frequency, where it eliminates any
outer feeder current on the unbalanced coax.
Hi ³ .".
³ / \
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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