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Re: [Amps] 807 transmitter

To: "The Bowers" <thebowerz@comcast.net>, <amps@contesting.com>
Subject: Re: [Amps] 807 transmitter
From: Karl-Arne Markström <sm0aom@telia.com>
Reply-to: Karl-Arne Markström <sm0aom@telia.com>
Date: Mon, 5 Feb 2007 21:51:46 +0100
List-post: <mailto:amps@contesting.com>
It appears that your tank coil inductance is too high.

For an operating Q of 12 the tank circuit capacitance would be in the 180 - 200 
pF range and
the associated inductance in the 8.5 - 9 uH range (about 2/3 the number of 
turns)

With the given coil data, the inductance is in the 20 - 22 uH range, and the Q 
will be too low
for an usable impedance transformation.

A suitable procedure would be to adjust the inductance for resonance, using a 
dip meter, with the tuning capacitor about 80 % meshed and the loading 
capacitor fully meshed. This will work for a start.

73/

Karl-Arne
SM0AOM
----- Original Message ----- 
From: "The Bowers" <thebowerz@comcast.net>
To: <amps@contesting.com>
Sent: Monday, February 05, 2007 8:56 PM
Subject: [Amps] 807 transmitter


> Has anyone built "K5DH's 807 CW transmitter" (Google) ?  I've built just the
> amp section but can't get it to load. I'm driving it with a sig gen at 3.9
> KC.
> 
> According to the on line calculators, L3 is at 10.3 uh, but should be 18.5
> uh., for 75 meters.
> 
> Has anyone found an error here, or is it just me?
> 
> Thanks guys, I appreciate the help.
> 
> Dana, W6TUO
> 
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