Yes it is definitely a core T82-75 from the labeling on the package.
Which parameter specifies that it has low resistivity?
Can this be used as a transmission line transformer of a balanced mixer?

Which ferrite material works well for the AM band around 1 MHz?

I can get core #43, 61, and 63.


Thanks for the input folks.

I wouldn't use ferrite at all for this application. A suitable iron
powder core would be a lot better:
=================================
Am I getting confused ? I thought the designation T82-75 identifies a
powder iron toroid , having a 0.82 inch outer diameter and is made of 75
type (mix)of material.
If ferrite it would be labelled FT82-75.

In my file I keep a snippet from QST ? in which Zack Lau (ARRL Lab)
highlights identification of Ferrite type of materials as follows:
Quote ---------------------------------------------------------------------
-----------
You may be able to grade your ferrites by resistivity. Just stick an
Ohmmeter across or bead in question and measure its resistance.
The readings you'll may not be narrowly definitive ,but if your parts
collection contains toroids of only a few types ,you may be able to separate
one mix from another according to Table 2.

Table 2
Typical Resistances of Small Ferrite Beads/Toroids

Material / Resistance
43 10 MOhm
61 30 MOhm
63 30 MOhm
64 30 MOhm
72 30 MOhm
73 20 KOhm to 100KOhm
75 5 KOhm to 20KOhm

Note by WJ1Z : It's a good idea to color-code your ferrite materials as you
require them (example : mix 43= red , mix61 =blue ,
mix 75 = green . When your cores arrive ,segregate them by mix and working
with each type in turn ,spread each lot on a sheet of newsprint and
spray-paint them (one face will will do) according to your color code .
Be sure to record and save the key !

Unquote --------------------------------------------------------------------
---------------

From the above table it shows that with its relatively low resistivity ,mix
75 contains relatively much iron ,which indicates the material is suitable
for low frequencies only , perhaps even not RF.

Frank GM0CSZ / KN6WH