[Elecraft] KPA1500 on AM

[Joe Subich, W4TV]

On 2021-02-04 3:12 PM, Grant Youngman wrote:
> Actually, that assumes that peak to avg is exactly 4.  Which it 
> rarely (never?) is with a real human voice.
It also assumes the modulation is symmetrical and that the mic is
wired with the correct polarity.

 > A monitor scope on the output is essential …

  ... and that the deflection on the scope is accurately calibrated
to PEP level (peak voltage across 50 Ohms).

73,

    ... Joe, W4TV


On 2021-02-04 3:12 PM, Grant Youngman wrote:
> Actually, that assumes that peak to avg is exactly 4.  Which it rarely (never?) is with a real human voice.
> 
> Aside from the legal (and oft disputed) aspects of AM power limits, you’re better off being conservative and setting drive levels for something under 375W carrier from the amp.  Maybe 250-300W.  That will ensure you have some headroom for voice peaks (especially if you have a good bit of positive voice asymmetry), keep the amp cooler, etc.  And no one on the receiving end will know the difference, anyway.  The referenced article is a good place to start.
> 
> A monitor scope on the output is essential …
> 
> Grant NQ5T
> 
>> On Feb 4, 2021, at 2:22 PM, Morgan Bailey <mbaileycrna at gmail.com> wrote:
>>
>> The max that you can legally run is 375 watts carrier. That on AM will get
>> you 1500 watts PEP. YMMV. I do not know the spex on the 1500 but that may
>> put you in the ballpark. Understanding linearity, for AM is covered here:
>>
>> https://www.w8ji.com/am_linear_amplifiers.htm
>>
>> If you want to run AM, this is where I would start reading.
>>
> 
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