[Amps] An Extra Thank You!

[Joe Subich, W4TV]

> I do have one final question for everyone here.  Knowing 
> these numbers, input, output, plate and grid, how does one 
> calculate the amp's gain and or efficiency?

Gain = 10 * log(Pout/Pin) 
     = 10 * log(450/20) 
     = 10 * log(22.5)
     = 10 * 1.352
     = 13.5 dB 

Efficiency (assuming grounded grid) = Pout/(Ip*Vp+drive) 

You don't give the plate voltage so I'll use 2000V as a 
placeholder ... 

Efficiency = 450 / ((.375 * 2000) + 20) 
           = 450 / (750 + 20) 
           = 450 / (770) 
           = 58.4% 

73, 

   ... Joe, W4TV 
 
 



> -----Original Message-----
> From: amps-bounces at contesting.com 
> [mailto:amps-bounces at contesting.com] On Behalf Of KB0NLY
> Sent: Thursday, March 05, 2009 3:40 PM
> To: amps at contesting.com
> Subject: [Amps] An Extra Thank You!
> 
> 
> Just wanted to post an extra Thank You to the reflector for 
> all those that have been patient with me and helping.  My 6M 
> amp project has been completed!  It was powered up and 
> brought to life today finally after much careful planning and 
> building.
> 
> Initial tests prove it's working rather well!  
> 
> Input 20w
> Output 450w
> Plate 375mA
> Grid 80mA
> 
> I was told to keep the GI7B at or below 400mA on the Plate 
> and 150mA on the Grid, i can do that easily.  It will make a 
> bit more power but it's maxing out my wattmeter now!  
> 
> I do have one final question for everyone here.  Knowing 
> these numbers, input, output, plate and grid, how does one 
> calculate the amp's gain and or efficiency?  I was trying to 
> make sense of the info in the handbook but it was slightly 
> over my head with all their calculations.  I'm looking for an 
> Elmer answer on this one!
> 
> Thanks and 73!
> 
> Scott KBØNLY
> 
> PS:  I will finish updating my website this afternoon with 
> pictures of the completed amp.
> 
> www.kb0nly.net
>