[Amps] Tuner Loss

[Shane Youhouse]

It seems to me that the losses in a tuner typically will be effected by  
the transformation ratio.


There is loss in any network that transforms impedance that I've been able  
to find.

Circulating current in the tuna WILL cause heating, just as it does in a  
pi net in your amplifier.  The pi, L, etc. doesn't care what the generator  
is (Cblock or literally, Cload).

Correct me if I'm wrong...  BUT, my tuna (Johnson Matchbox, 6 inch spaced  
#10 feeders to 160 inv v) gets warmer the larger transformation ratio is  
being effected.


--Shane
KD6VXI


On Thu, 10 Mar 2011 18:19:44 -0800, Bill, W6WRT <dezrat1242 at yahoo.com>  
wrote:

> ORIGINAL MESSAGE:
>
> On Thu, 10 Mar 2011 11:40:19 -0500, "Carl" <km1h at jeremy.mv.com> wrote:
>
>>
>> 165W of loss in a well constructed tuner shouldnt even be a discussion
>> point. Tank circuit loss in a 1500W amp is much more and we accept it as
>> normal.
>
> REPLY:
>
> Absolute nonsense. Apples and oranges.
>
> Reactances such as found in a properly designed tuner should be nearly
> lossless. A linear amplifier can not be lossless because a sine wave is
> being amplified. As the tube transitions from zero anode current to peak
> anode current and back again, it appears as a changing resistance over
> the RF cycle. As a resistor, it dissipates power and this is
> unavoidable.
>
> No such thing happens in a tuner.
>
> Basic tube and AC theory, Carl. Time to hit the books.
>
> There are amplifiers which go from zero anode current to max anode
> current and back in a very short time and do not have the dissipation
> problem, but those are NOT linear amps. Class D is one such example.
>
> 73, Bill W6WRT
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-- 


It's a sad state of affairs when your tubes don't have handles but your  
dummy load does.