F5LCI wrote:
"The window size is abt 0.90 x 1.60 metres---."

The wavelength is near 3 metres at 100 MHz. So, the long dimension of
the window is slightly more than 1/2-WL. It can be considered (2)
short-circuited stubs back-to-back. At the low frequency end of the
band, the stubs may be near 1/4-wave and the antenna will be resonant.

Feed the window frame across its narrow (0.90 metres) dimension in the
centre of its 1.60m length.

The frame may be shorted acress its top and bottom to resonate the loop
(2 stubs) at higher frequencies for more response.

Kraus advises not to expect an efficient antenna made this way because
it has too little conducting materiel unless the frame is substantially
fattened. Plenty of folded dipoles and unipoles do very well without a
lot of conducting material. The difference must be in the feed
arrangement.

But, the application is for receiving, and you don`t usually need
efficiency, just good signal-to-noise ratio for success.

The window frame is there for a trial. With clips and feedline it can be
tried.

F5LCI can crank or swing his "loop" away from its closed position to see
if there`s any directional advantage. It is surrounded by conducting
materials which often cause directionality, intended or not.

Best regards, Richard Harrison, KB5WZI