Cecil Moore wrote:a couple of points to make.

When I suggested that 40 turns might be required for 75m,
I was chastised for my statement. Note that the above URL
contains data on a 38 turn choke on a 4.5" coil form for
75m operation. The choking impedance is 1300 ohms on 75m.
Parallel self-resonance on 75m would require more turns
than 38.

8 turns loose wound in a 6.625" diameter bundle looks like an effective
single band balun for 80m (approx 500 ohms). W6TC's voltage balun (Feb
1980 Ham Radio) uses 6 turns loose wound on ~5" diameter (8' total
length) but adds a compensating winding in the opposite direction. It
has nice characteristics for 40-160m but can only be used with balanced
antennas (e.g. dipoles, inverted-Vs, etc). I've used a W6TC balun for
many years on a trapped 80/160 inverte-V.

73, Bill W4ZV