Screen grid modulation final tuning

[Knightt150]

Hello Again: Thanks for the screen grid modulation info now, I would like to know why a controled carrier or a screen grid transmitter tunes differently than a plate modulated rig. The plate modulated rig you can dip the plate and increase the loading. But if you do that on a screen grid rig the modulated output is lower. You can peak the plate and peak the load and the modulated RF output is high. This seems odd because a screen grid transmitter tunes the same as a plate rig.
Thanks John W9BFO

[The Slab Bacon]

A screen modded final DOES NOT TUNE THE SAME AS A PLATE MOD FINAL!! 
(True screen mod and NOT controlled carrier) Yea, you can tune and load it for max carrier, but you will not be loaded heavily enough to make the audio peaks. And the audio will sound like sh!t.

You must first tune and load for max blowsmoke, then INCREASE (load more heavily) the loading until the carrier output drops to about 1/3 the DC input to the final. this will insure that the final is loaded heavily enough to make the audio peaks for modulation. It will also lessen the amount of screen dissapation deamatically if you are using a tetrode. Loading a scream mod final is very similar to loading a leanyour amplifier. If you look at your outpot on a scope, you'll see the difference quickly as it wont make any positive audio peaks.

If it is operating properly, the plate efficiency of a scream mod rig should be around 33-40% at resting carrier conditions, and reach somewhere around 70% on audio peaks. I have been running my scream mod 4-1000A that way for years.

                                                           the Slab Bacon