----- Original Message -----
From: "Bill Turner" <dezrat1242@yahoo.com>
To: "Amps" <amps@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
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|