[Amps] ferrite in RF chokes for PAs

[Peter Voelpel]

The better news is that it worked in many thousands of amps  built by
Rohde&Schwarz from about 1958 to 1990 for the military and other gouvernment
use.
The early version was 500W AM/CW/FSK with a single QB5/1750, later 800W
AM/CW/FSK with the same tube, and then the version with the YL1050/RS1072C
built for any mode 1-30MHz and up to 1500W output 24/365.
The YL1050 operates at 3KV up to 1.4A.

73
Peter


-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Jim Brown


>Plate RF choke has an appreciable DC current component in it. This 
>lowers the effective mu of the ferrite, and makes it less effective as 
>a choke.

YES!  The good news is that this can be predicted from mfr data sheets. 
The bad news is that you probably won't like the prediction. More bad news
-- the DC will also cause heating, very possibly overheating.