9:1 balam feed long wire antenna

On ebay and from various other sources, a long wire antenna can be found which is fed through a 9:1 balam step down. The long wire measurement is next to that of a full wave wire on the 40m band. However as the antenna is offered as a HF antenna, some shown as operational on 6m, I wondered what the impedance would be for an auto atu to see in order to match the long wire to the transmitter / receiver.

Below is a graphic illustrating the calculations:

On the assumption that the extra wire length would provide a greater EMF coupling to the etha, the antenna efficiency shows the effective radiated signal on that particular band assuming a 100watt transmitter.