Taking Gil's idea for using an 82 toroid I built this 64:1 transformer. Although the 3D printed box is a much more efficient use of space, I don't currently own a printer. I did find that a Hammond 1551HBK is about as good as it gets as far as size and ruggedness. The overall dimensions are 60x35x20mm. This does not have a ground connection but i have found that a small coil in my coax generally takes care of any RF on the shielding. IMG_5128.jpg
Looks great! Hammond makes nice cases..
Gil.