Yes, powdered iron (I believe it's "iron dust" in the Queen's English)
is what you want. The major manufacturer of suitable cores is
Micrometals. Their products are sold by Amidon and others. Give their
web site a look for general info, and a google search should yield some
retail sources. For HF work, type 6 generally gives the highest Q, with
type 2 in second place.

Roy Lewallen, W7EL

Charles R. Ott wrote:
Paul,

You need to look at powdered iron cores instead of ferrites.

K5HJ