Is that a 160m mono band amp with a loaded Q of 12 in the tank circuit or is
your 160m toroid coil just delivering one halve or less of the total
inductance on 160m?
73
Peter
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Bill Turner
Sent: Sonntag, 6. Oktober 2013 05:44
To: Amps
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
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