[RFI] ADSL2+ modem crashing solved using power line filter and choke

[Don Kirk]

For many years I have had AT&T DSL service and had to use a home made
filter (designed by OZ1CTK) on the phone line feeding the the DSL modem in
order to prevent the modem from crashing when transmitting on 160 meters
(running 100 watts).

Today AT&T switched me over to their Uverse service which I believe is
ADSL2+ based on what the technician told me, and as soon as I started
transmitting on 160 meters running 100 watts the new ADSL2+ modem would
crash.  We tried using my OZ1CTK ADSL filter, and as I suspected it did not
allow the new modem to operate properly (no internet connection).  I then
decided to try some filtering on the power line cord that feeds the power
supply for the new ADSL2+ modem, and to my surprise my new modem so far has
been functioning fine (no longer crashing when I transmit on 160 meters).
The new Modem is a Motorola NVG580, and my filter on the 120 volt power
line  feeding the NVG580 power supply consists of a commercial EMI filter
(Delta Electronics 10DRCG5) and 14 turns of the power cord wound on a 2.4"
OD Fair-Rite #31 mix toroid core (based on the K9YC hams guide to RFI
document).

Just FYI,
Don Kirk (wd8dsb)