[AMRadio] RE: negative cycle loading


W7QHO at aol.com W7QHO at aol.com
Tue Apr 6 17:16:43 EDT 2004


Brett,

Are you using the three diode circuit at   <
http://www.amwindow.org/tech/htm/3diodeka.htm>?
If so, this thing will clip all negative peaks that cross the "keep alive" 
level.   How abruptly would depend on the internal impedance (i.e., stiffness) 
of the keep-alive supply but would give essentially the same effect as clipping 
in the PA by crossing the zero line. This is where your splatter is coming 
from.   Give the circuit at <http://www.amwindow.org/tech/htm/3diode.htm> a try. 
  I've had good results with this setup adjusted to give up to 200% in the 
positive direction without overmodulating the negative side.   For the resistor, 
I've found a value around the load impedance presented by the PA works well. 
You must use a scope to adjust this scheme.

Good luck.

Dennis D. W7QHO
Glendale, CA


--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
The reason this message is shown is because the post was in HTML
or had an attachment.  Attachments are not allowed.  To learn how
to post in Plain-Text go to: http://www.expita.com/nomime.html  ---



More information about the AMRadio mailing list

This page last updated 19 Oct 2017.