>
>I'm re-doing some RTTY interfacing here in the shack and just wonder -
>can you use the same ferrite core for 2 different cables wound
>together? Sure would make for a neater lashup. Thanks and 73
>Tom W7WHY
The supposed purpose of ferrite cores on interface leads is to suppress
any stray common-mode RF currents between different parts of the system
(most often, between the transceiver and the PC). In that case, it's
probably OK to use the same core for bundled conductors that are going
to the same destination.
But in real life it isn't always so clear-cut. Many people's idea of
"using ferrite" is a single pass through one ferrite bead, which doesn't
make a very effective RF choke... but it does make quite an effective RF
transformer. If you pass several conductors through the same core, the
transformer action means that common-mode RF current carried on one
problem conductor will then be shared onto all the others conductors as
well... so in some cases sharing a common core can make RFI problems
worse.
Because of the risk of sharing common-mode current, it isn't a good idea
to use a common core for conductors that are going to different
destinations.
The best strategy is first to bond the chassis and frames of all
equipment together, using the shortest possible length of low-impedance
conductor (eg a broad strip of copper along the rear of the table-top).
Do that bonding first, and then see if any ferrites are needed at all,
and try to identify and treat the individual problem conductors.
73 from Ian GM3SEK
>-----Original Message-----
>From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of Tom
>Osborne
>Sent: 29 September 2014 23:55
>To: rtty@contesting.com
>Subject: [RTTY] Multiple cables on 1 core
>
>HI all
>
>I'm re-doing some RTTY interfacing here in the shack and just wonder -
>can you use the same ferrite core for 2 different cables wound
>together? Sure would make for a neater lashup. Thanks and 73
>Tom W7WHY
>_______________________________________________
>RTTY mailing list
>RTTY@contesting.com
>http://lists.contesting.com/mailman/listinfo/rtty
_______________________________________________
RTTY mailing list
RTTY@contesting.com
http://lists.contesting.com/mailman/listinfo/rtty
|