[AMRadio] A question about a National NC 2-40D receiver

W5AMI ars.w5ami at gmail.com
Fri Nov 8 14:55:19 EST 2013

Thanks for that info Jim!  If I ever pair mine up, I know what to do now!

Brian / w5ami

On Fri, Nov 8, 2013 at 1:41 PM, JAMES HANLON <knjhanlon at msn.com> wrote:

> Kevin,
> The NC-240D was designed to be muted by an attaching an external relay to
> the BSW terminals on the back.  The BSW (B+ SWitch) terminals are in
> parallel with the B+ switch section of the POWER SUPPLY rotary switch
> located beside the S-Meter.  If you leave this switch in the B+ OFF
> position, you can turn the receiver off (mute it) by opening the connection
> across the BSW terminals, and of course return the receiver to operation by
> closing the connection across the BSW terminals.
> In case you want to operate CW and to use the NC 2-40D to monitor your
> transmitter, you can use a SPDT relay with the swinger attached to receiver
> chassis ground.  Break the lead on the RF Gain control that goes to ground
> and put a 10K or so pot in between the RF Gain Control connection and
> ground.  Attach the junction between this "CW transmit volume" control and
> the RF Gain control to the relay contact that is grounded when the relay is
> in its "receive" position.  Attach the other relay contact to the antenna
> input terminal.  In the "receive" position, the relay attaches the bottom
> of the RF Gain control to ground and the receiver operates normally.  In
> the "transmit" position, the short across the "CW transmit volume" control
> opens and a short-to-ground is placed across the antenna input terminals.
>  You then adjust the "CW transmit volume" control for appropriate volume
> while sending.
> Enjoy your 2-40.  It's a great receiver.
> Jim, W8KGI
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