At that times I had a broadband transformer 9:1 from an old marine transmitter,
the transformer worked good at 160- through 10 meters, but, unfortunately,
the transformer had small sizes and it was very hot already at
50 Watts. Transformers made on a yoke ferrite core from 27” TV
worked good at 200 Watts…
I experimented with antenna loads of 450 and 300 Ohms however, antenna
with these loads was hard to match.
Recently using MMANA (References 1)
I simulated parameters of the antenna loaded to 600, 450, 300
Ohms. For simplification it was supposed that the
antenna is located in a free space. Table
1 shows the data.
The table shows that the antenna has best SWR at 160 through 10 meters
only at the 600 Ohm load. I can notice, that in real conditions,
the antenna has SWR better then shown by the Table
1 because losses RF energy in the nearest subjects.
The table shows that the antenna is ‘dead’ at ranges 160 and 80 meters,
but at good propagation you could make QSOs. Antenna gain is small
at 40 through 10 meters too, but already even at rather average
propagation (and 100 Watts in the antenna) I could easy make QSOs
using the antenna.
MMANA shows that
the antenna has one sided directivity, but I could not see that
when I have used the antenna. See screenshots of the antenna simulated
by the MMANA.