[CQ-Contest] dsl rf filter

N6KI Dennis Vernacchia n6ki_73 at sbcglobal.net
Sun Nov 19 04:20:28 EST 2006


I am using -31 mix Ferrite on all my DSL connections and seems to work 
fine to stop RFI

Mouser Electronics has some FAIR-RITE snap on ones that also may snap on 
RG-213 coax
tightly in case you also want to build current Baluns

Mouser Part #:, 623-*0431167281  less than $2 ea*


Also 2.4 inch Donuts from DEXTER MAGNETIC TECHNOLOGIES
800/775-3829 877/221-5052

Fair Rite Part Number 2631626402

I have been buying these at $3 in 100 quantity but
see what they are in small QTY


73, Dennis N6KI

David Robbins K1TTT wrote:
> I recently switched from isdn to dsl, which of course meant a new round of
> rf filtering for the new dsl modem/router.  Ferrites on the power and phone
> line did pretty good, but not quite enough for the low 80m V and low 40m
> beam, both of which kind of aim through the phone line and aren't that far
> from the shack.  While picking up some capacitors to build my own line
> filter at, of all places, radio shack, the clerk actually came up with an
> interesting product.  They have a 3-30mhz rf line filter for 2 line phones.
> (279-151).  Its basically a balanced LC lowpass filter.  At normal home dsl
> speeds it worked fine right out of the bubble pack, I only know this because
> for about 3 weeks my isp was fighting with verizon trying to get me up to
> the 3mb business line speed.  When they finally got the speed up to where it
> belonged the line loss from the filter was too high.  For those who don't
> know about dsl it uses frequencies up to about 500khz.  So I adjusted the
> filter a bit by removing the 4 inductors for the 2nd line and putting them
> in parallel with the 4 for the line I was using, this should effectively
> reduce the inductance and shift the passband up a bit higher... this seems
> to be working, it still has a bit more loss than I would like, but does
> effectively block 80m and 40m.
>
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>  
>
>
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