T300 Iron Powder Toroid Radio Inductor Core Amidon Micrometals Toroidal Coil Form T-300

This is one item of new iron powder toroidal inductor core from Amidon - Micrometals available in various frequency grades. These are the T300 size where the outer diameter is 77.6mm, the inner diameter is 48.6mm, and the height is 13.3mm. These are quite chunky units capable of high power handing.

These are used to make high Q inductors for use in matching and filtering.

T300-2 Type 2 Red have an AL value of 11.4 nH/N^2 and are nominally intended for high Q used in the 3 to 30 MHz range, though the bigger cores are frequently seen in professional equipment down to 1 MHz.

T300-26 Type 26 Yellow-White have an AL value of 80 nH/N^2 and are intended for high Q use below about 2 MHz in the LF / MW frequency range. If you are using the core as a transmission line transformer (balun) choking impedance, you can get a fairly high impedance down to lower frequencies than usual using these particular cores, making them handy as a so-called balancing balun at MW or 160m band 'short' TX antenna feed points.

A seven turn test winding and results are shown in the secondary pictures.

These are heavier items.