National NC 300 information

Garey Barrell k4oah at MINDSPRING.COM
Tue Nov 19 09:18:47 EST 2002

John -

The '300 has a switch on the AF Gain control that is actuated when the
control is full CW.  Normally, the "RF Gain" control is actually an "IF
Gain" control.  For SSB and CW, the AF Gain is turned max CW to actuate the
switch, and then returned to about half scale.  With this switch "on" the
RF Gain control controls both the IF stage  _and_  the RF stage gain.  The
volume is then controlled with the RF Gain control.  This was SOP with ALL
receivers with diode detectors for CW and became imperative when SSB first
reared it's ugly head!

Don't know if the '303 does this or not.

See, it  _does_  pay to read the directions!!  :-)

Seems like I recall an FSN or perhaps a mod that changed some AGC resistor
values and reduced the size of the coupling cap into the product detector
to improve the signal handling capability of the 300, but I can't find it
at the moment.

73, Garey - K4OAH

At 06:43 AM 11/19/2002, john wrote:
>In both the 300 and the 303, it's imperative to turn the RF gain
>way back and throttle the rx with the AF gain. The 303 manual says
>that explicitly. I found it (naturally) after complaining about the 303's
>SSB reception. Following the instructions, it now sounds good.
>John wb5oau
>At 09:19 PM 11/18/02 -0600, john w. king wrote:
> >
> >Looking for mods for my NC 300 to enhance SSB reception and strong signal
> >handling ability. Any suggestions where info might be found.  How do I get
> >to a reflector for National equipment? 73, and Thanks. John, K5PGW
> >

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