The DS1 and 40m add-on coil have been retired. They have been replaced with the CLV Center Loaded Vertical Antenna. The CLV has higher Q and efficiency moving the base loaded coil to the center of the antenna. It can be seen at:
The DS1 and 40m add-on coil have been retired. They have been replaced with the CLV Center Loaded Vertical Antenna. The CLV has higher Q and efficiency moving the base loaded coil to the center of the antenna. It can be seen at: