Amateur Radio Curiosities--Passive Audio Filter.

Passive Audio Filter
(http://www.eham.net/article/34854).
Accessed on 07 December 2015, 21:52 hrs, UTC.
Author:  Alan Applegate (K0BG).

An excellent tutorial on the design and use of passive audio filters for older tube and hybrid-tube transceivers.  Sometimes, simple solutions are best.  Alan does an excellent job of explaining how to build and use these passive devices.  Alan also maintains an interesting, informative website focusing on mobile HF antennas.  You can get more antenna ideas at:  http://www.k0bg.com.

Aloha es 73 de Russ (KH6JRM).