Topband: DSL knocks out when on TopBand

[Jim Brown]

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