There is another alternative to using an MN-52 box to turn the loop. Bendix made an MR-15 crank unit, and an MN-22 or MN-40 azimuth indicator. All using the same MC-124 type tuning shaft. In the case of the MR-15 and MN-22 or -40, you would need two spline shafts to make the installation. Jack Antonio WA7DIA/4