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Re: [Amps] Need for bias switch (CW/SSB)

To: "Steve Flood" <kk7uv@bresnan.net>, <amps@contesting.com>
Subject: Re: [Amps] Need for bias switch (CW/SSB)
From: "Carl" <km1h@jeremy.qozzy.com>
Date: Sun, 17 Jan 2016 13:08:33 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>
The best way to tell if your CW signal is objectionable is to look at it on a spectrum analyzer which is built in to many SDR rigs, find someone running one and ask him.

"just" cutoff is a twilight zone and true Class C is very dependent upon the bias being at least 2X the cutoff voltage plus grid drive requirements are much higher in order to overcome that bias.

These days ham band Class C is only good for AM or FM. I run linears in Deep B for AM so say if idle current is normally 200 ma I run about 40 for improved efficiency and less wasted heat which keeps some marginal transformers happy.

Carl
KM1H



----- Original Message ----- From: "Steve Flood" <kk7uv@bresnan.net>
To: <amps@contesting.com>
Sent: Sunday, January 17, 2016 8:36 AM
Subject: Re: [Amps] Need for bias switch (CW/SSB)


I have an adjustable bias where I can run a little ZSAC for Class AB. But I can dial the bias until it *just* cuts off and I often use this setting for CW. What class am I running when I do so? I've heard it informally called
class B/C.   Running CW at that setting, or even a little deeper bias into
Class C territory does not create any reported key clicks here.

Steve KK7UV



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