With recent WSPR tests on the 630m 472kHz band using only 5W into the very inefficient resonant antenna, a problem has been found with causing interference to the ADSL modem that causes erratic performance with poor and intermittent data throughput. Another Ham has also found the same issue and has turned off his WSPR after finding the same issue. I have an overhead telephone cable and the other station has underground cabling. I expect this would also affect VDSL ( NBN ) and if you ran higher power it would cause problems to many neighbours. Tests on the AM band with modern portable direct conversion receivers, have also indicated that weaker AM stations are knocked out due to overload, and on some strong stations a tone is heard in the background when the WSPR is transmitting. There is no way of filtering the ASDL on the telephone line as it operates in the same frequency range of 26kHz to around 1.1MHz, so it might be worth considering limiting operation on the band to keep interference to a minimum.
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