[AMRadio] Re: Looking for Linear Amp

[Gary Schafer]

Geoff Edmonson wrote:
> I spewed my drink all over the monitor when on Friday 19 December 2003 01:41, 
> W7QHO at aol.com said (and I am -not- making this up!)::
> 
> 
>>In a message dated 12/18/03 10:41:35 PM, eccm at swbell.net writes:
>>
>>>It has been my experience that of everything is workig right, and the
>>>output circuit is efficiently designed, the maximum reliable power
>>>output from a linear amp running standard AM is about equal to half
>>>the total rated plate dissipation of the tube(s). i.e. for a pair of
>>>6146's, 20-25W carrir, 80-100W PEP.
>>
>>Good rule of thumb.   I've operated my home brew 3-1000Z linear on legal
>>max AM.   The tube is dissapating about 800 watts under carrier only condx
>>in this mode and the plate runs a nice bright yellow-orange!
>>
> 
>  Dennis. what are you calling "legal max AM"?
> 
> The only legalities we have anymore, is 1500w PEP output.
> 
> Depending on the natural asymetricalness of your voice, will depend on how 
> much PEP output you have (which is quite difficult, at best, to measure).
> 
> The Rule of thumb is, if you modulate a carrier to 100% with a sinewave, the 
> Peak Envelope Power Output is 1,500 watts.  That would the carrier power(x4). 
> or 375w of carrier output, or (roughly) 500w DC input to the final.
> 
> The problem with that is, we don't speak in sine-waves ;-)
> 
> For more information on figuring PEP power, see 
> http://www.qsl.net/wa5bxo/amplitude-modulation-and pep.htm
> 
> For a great write up on asymetrical audio, see 
> http://www.qsl.net/wa5bxo/asyam/aam3.html
> 
> Dig around the website.  Be careful, though - you might learn something ;-)
> 
> Happy Holidays
> 73 = Best Regards,
> -Geoff/W5OMR
> 

Geoff,

What's wrong with what he said? He is talking about LINEAR operation not 
  a plate modulated final. His figures are correct for "rule of thumb". 
Remember 33% efficiency for the carrier in linear AM operation.

73
Gary  K4FMX