[Amps] Tuner Loss

[Carl]

----- Original Message ----- 
From: "Bill, W6WRT" <dezrat1242 at yahoo.com>
To: <amps at contesting.com>
Sent: Thursday, March 10, 2011 9:19 PM
Subject: Re: [Amps] Tuner Loss


> 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.
>

I would expact that sort of comment from you.

It was only meant to show that the coil heat we take for granted in an amp 
is rarely a concern and many (even the most expesive) take no special 
cooling measures.

Tuner design is strictly cost driven so marginal components are used. An 
ideal 160-10M 1500W + tuner using 4500V 500pf variables and an edge wound 
rotary inductor would cost a couple of thousand dollars if sold 
commercially.


> Reactances such as found in a properly designed tuner should be nearly
> lossless.

Losses in your typical commercial tuner are in the inductor as the low C 
used on 80-160 are the problem. This was shown decades ago in ARRL reviews 
of available tuners.On 160 in particular it was shown that a "matched" 
condition was possible with the inductor absorbing the full power.


> Basic tube and AC theory, Carl. Time to hit the books.

Yes you should Bill, and more than one.

Carl
KM1H