On 7/16/2012 6:10 PM, N1BUG wrote:
> I had exactly the same problem, tried the same "cures" you have. The
> problem is ADSL uses frequencies up to 1.1 MHz. The modems are
> easily overloaded by 1.8 MHz RF. Nothing worked until I built this
> simple filter designed by OZ1CTK:
Looks great, Paul. Thanks for posting this.
This is a differential mode filter, so it suggests that some or all of
the telco cable feeding the modem isn't twisted pair, or isn't very good
twisted pair. SO -- another solution could be replacing that poor cable
with CAT5, using the pair within the CAT5 that has the highest twist
ratio. Shielding is NOT important, but TWISTING is. Un-twisted cable is
notoriously bad for RF rejection.
KL7RA's advice is also quite good -- the problem is poor rejection of
the 160M signal by the DSL modem and/or its wiring, and we should lean
on our service providers to fix that, either with new hardware/wiring,
or filters, or both.
73, Jim K9YC
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