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RE: Drake 2880 Modifications



Thanks, Ed..............

My brain was focused on the normal
zener voltage regulator circuit.

Obviously I didn't look closely
at the schematic.  Since the zener
is not referenced to ground, the
drop is from the 10V supply down
to 7.3V.

In addition, I overlooked the 2V7
value on the zener, forgetting that
the V stands for the decimal point.

Thanks for refreshing my (diminished)
memory on zener diodes and component
value designations.

Bill, WA6QGR

-----Original Message-----
From: Edward Hall [mailto:wc0y@hotmail.com]
Sent: Monday, February 19, 2001 10:58 AM
To: billwashburn@mediaone.net
Subject: Re: [amsat-bb] Drake 2880 Modifications


My understanding of G3PHO's circuit is that the 2.7V zener diode drops the 
10V supply to 7.3 volts for the drain.  I recently modified a 2880 in a 
similar manner, with a 3.0V zener in the drain circuit to make a 7V drain 
voltage.

73,
Ward - WC0Y


>From: "william washburn" <billwashburn@mediaone.net>
>To: "Amsat-Bb" <amsat-bb@AMSAT.Org>
>Subject: [amsat-bb] Drake 2880 Modifications
>Date: Mon, 19 Feb 2001 08:54:49 -0800
>
>Folks,
>
>The G3PHO Drake 2880 Modification
>page shows the LNA circuit using
>2V for Vd on the MGA86576.
>
>The MGA86576 specs I have read show
>a Vd of 5V (and even 7V at high temp).
>
>Does anybody know why Vd was set at 2V?
>
>Thanks,
>Bill Washburn, WA6QGR
>----
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

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