[Amps] water cooled 160m amp.

[TexasRF at aol.com]

Jim, if you look art the curves for any of these tubes you will notice that 
 the plate voltage swing can't be allowed below four or five hundred volts  
without excessive grid current (or screen current in the case of a  
tetrode).
 
That means the total voltage swing is plate voltage minus 500 volts  
typically. If you are using 2700 vdc on the plate, the total swing is 2200 volts  
which is 81.5% of the plate voltage.
 
If you run 4000 volts, the plate swing can be 3500 volts or 87.5% of the  
plate voltage. The difference between the two voltage levels makes the higher 
 voltage have about 7% more efficiency.
 
Of coarse this added efficiency may not actually be available if it makes  
the power output exceed our 1500 watt limit.
 
Also, the higher plate voltage will dictate a higher plate load impedance.  
Usually higher load impedances come with a higher loss due to the Q loaded 
being  higher when compared to Q unloaded. A really good plate inductor will 
mitigate  this effect to a large extent, especially at higher frequencies.
 
73,
Gerald K5GW
 
In a message dated 2/9/2010 8:16:37 P.M. Central Standard Time,  
Jim.thom at telus.net writes:

From:  "DF3KV" <df3kv at t-online.de>
Subject: Re: [Amps] Water cooled 160  meter amplifier..
To: <amps at contesting.com>
Message-ID:  <1Nep7B-0Om3CC0 at fwd00.t-online.de>
Content-Type: text/plain;  charset="us-ascii"

That is the same efficiency as with a 8877 at that  voltage.
It will be much better at higher anode  voltage.

73
Peter

##  why should the tank eff   increase.. with higher  B+   
voltages applied  ??   I can see gain going up a bit. 
I can also see more power  out.  What has B+ level 
have to do with tank eff ??? 

later...  Jim   VE7RF


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