[AMRadio] Class C modulation

[wwd at netheaven.com]

Something is wrong with your configuration or maybe weak tubes if you are
seeing results like these.

The goal today (often) is a setup which can achieve well beyond 100%
modulation to allow room for positive peaks (male voice pattern) as well
as audio processing to maximize intelligibility AND full frequency range
impact. The last thing you want to transmit is a totally flat response
which shows up in the receiver as dull and lifeless. Anyone who has heard
Tim, WA1HLR, from his home QTH has a good idea of this concept brought to
perfection. To pick a well known example; there are a number of others. 

So you really need TWICE the tubage in the modulator as in the Class C
final. With adequate mod-iron and power supply, too.

Bill        N2KQA


In <018e01c1cf5d$ccb051a0$0200a8c0 at hamhome.net>, on 03/19/2002 
   at 09:50 AM, "w5omr" <w5omr at yahoo.com> said:


>: Question:  Have you ever built a transmitter using 4-400's modulated with
>: 810's or should I use 250TH tubes to modulate a pair of 4-400A's.  Thank
>: you.

>I've had a pair of 250TH's in the final of my homebrew rig, since I've
>had it.

>I've modulated that thing with a pair of 811's, 810's, 4 810's in p-p
>parallel, and 250TH's.  the next incarnation of "The Titanic" will be
>with a pair of 450TL's (if I can ever slow down at work, enough to get
>started on it!)

>So far, the 250TH's have been superior, modulating a pair.  However, do
>NOT discount a pair of 811's.  Those dudes put out more audio than a pair
>of 810's did.  

>Sometimes you just gotta forget what the Handbooks say, and go with  what
>works.  

>I switched from the 811's to the 810s, because the handbook said 810's in
>class B, have like 700w output.  A far cry from the 811 classification,
>but the kicker was, there was more audio out of a pair of 811's, hands
>down.

>73 = Best Regards,
>-=Jeff/W5OMR=-

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