[Heathkit] Heath Warrior as an AM amplifier

[Eddy Swynar]

On 2012-01-17, at 8:21 AM, Rick Poole wrote:

> Yes, but 200 watts is half an S unit, or less, than what I'm getting 
> now.  Doesn't seem worth the effort unless I can get close to a full 
> S unit improvement.


Hi Guys, 

Years ago my OT radio friends W2UJR, KA9QLF, and others, told me this "truism" when it comes to using an external linear amplifier to boost one's AM signal, specifically, the maximum carrier output that you can safely obtain from the amplifier is equal to ONE HALF of the amplifier tube's plate dissipation power...

Example: you are using a pair of 813 tubes in an amp---each tube is rated at 125-watts plate dissipation, for a combined total of 250-watts. HALF of 250-watts equals 125-watts, so you can safely draw that output, i.e. 125-watts, from the two as your AM linear.

Some other points to consider: doubling your power output translates to an increase of just 3 db., which probably is not even detectable to the human ear. Also, one S-unit equals, roughly, 6 db. A 10 d. increase in signal strength WILL be noticeable to the human ear...

There, 'nuff said! You do the math at your end, using what you might have at your disposal, & draw your own conclusions as to the utility of using an AM linear amplifier. Years ago I used my 2x813 amplifier to boost the 10-watt AM signal from a HB rig that I had which used a 2E26 in its final modulated PA stage: was it worth it...? For a 10+ db. improvement, I think it was...Would it have been worth the trouble to amplify the output from a Johnson Ranger in AM...? I think not.

~73~ de Eddy VE3CUI - VE3XZ