[Amps] 160M PI network Toroidal Coil

[Carl]

----- Original Message ----- 
From: "Bill Turner" <dezrat1242 at yahoo.com>
To: "Amps" <amps at contesting.com>
Sent: Saturday, October 05, 2013 11:43 PM
Subject: Re: [Amps] 160M PI network Toroidal Coil


> ORIGINAL MESSAGE:          (may be snipped)
>
> On Sun, 06 Oct 2013 00:25:36 +0000, Manfred wrote:
>
>>You are wrong regarding the loss. The loss isn't "essentially zero",
>>unfortunately. Such a coil will likely end up having a Q between 300 and
>>350, perhaps lower if other metal objects are too close to it, or if it
>>uses some lossy support. Now if the loaded Q of the tank circuit is 12,
>>as is often done by design, then the coil will loose about 4% of the RF
>>power. At 1500W output that would be 60 watts, which is enough to make
>>that coil very hot, unless there is a strong stream of air cooling it.
>
> REPLY:
>
> I stand by what I said. I have such a coil in my homebrew 8877 amp using 
> #4
> wire and it runs barely warm with the key down. I call that "essentially
> zero" in the sense you'll never notice it.
>
> 73, Bill W6WRT

However the thread is about a SB-220 which may make 1300W PEP on a good day 
and will never be used for RTTY at more than half that due to the wimpy PS.

A pair of T200-2 toroids works fine for that as well as the thousands of 
Alphas and other amps that have used them at up to twice the power.

Carl
KM1H