Attention All Hams, Please Help with HVDC QRN Experience

Attention All Hams! Anyonewho had experience with QRN caused by high voltage DC transmission lines(HVDC), please share your experience with Cornell Drentea - KW7CD who isconducting a study on this problem. <o></o>
HVDC transmission linesare used in some countries including the United States and use converted DCenergy into pulsed electrical energy and transport it over long distances, tobe rectified back to DC at the receiving points much like a distributed switchingpower supply. Please help if you have experienced such QRN at your QTH. Pleasedescribe the nature of the QRN, its severity and the proximity of the problem. Sendyour inputs to CDrentea2@aol.com<o></o>
Thank you.<o></o>
<o> </o>
73, Cornell - KW7CD <o></o>