I have an Antenna Tuner - an MFJ 16010 which I used years ago but it does nothing to stop that 50,000 watt 680 Hz blowtorch interference on the Shortwave Bands with the 80 Ft Antenna.

http://www.mfjenterprises.com/support.php?productid=MFJ-16010

The MFJ-16010 is configured as a low-pass filter, so it is probably not ideal for eliminating BC overload.

Do you have a good earth ??? Any ATU can't do much without an earth.

.......... Zim