Ancient_Hacker wrote:

It simply consists of a 2.2mH choke in both lines.

Like these
http://uk.farnell.com/jsp/endecaSear...jsp?SKU=432167

I'll post a pic in abse.

I'd expect a common mode choke to be better of course.


I *hope* they use a more appropriate choke than that one-- if you read
down a bit the specs say it resonates at around 1.35 MHz. That means
it's more of a capacitor than anything else above that frequency, and
not a very good inductor in the AM band. Although likely to be good
enough at the lower DSL frequencies.

A good 2.5mH RF choke is pie wound to minimize capacitance and is good
up to 30MHz at least.

Well, they look like those parts. See the pic in a.b.s.e.


Opening up a DSL filter here shows a somewhat better design -- a two
solenoid-wound chokes and two mylar capacitors across each end.

But that still is not quite optimum-- the DSL frequencies that filter
tries to choke out are not quite as high as the AM BC band.

No ? I thought they coincided with low end of AM quite accurately in fact.


SO a pair
of *good* RF chokes will probably work better than the DSL filter type
of chokes.

Probably so.

Graham