On Tue, 9 Aug 2005 23:41:27 +1000, "Gary Smith"
wrote:

Hi, i would like to build a variable attenuator for 450-500MHz. It will be
used for RDF assistance.
Could people please give me construction details of different designs or
different ideas on the topic.

Hi Gary,

You don't need precision, so building your own is a good option. The
circuit would be a switched, cascaded pi-network of resistors also
known as a decade attenuator.

You need only three resistors and a DPDT switch for each section. The
traditional sections add 1, 2, 2, 5, 10, 20, 20, 50 dB of attenuation.
For RDF you can skip the first 3 or 4 sections.

73's
Richard Clark, KB7QHC