what is the use of IF TX quartz filter on the KREF3 board ?

[giuliano-8]

I see on the K3 KREF3 schematic a quartz filter ( 8215 KHz BW= 4 KHz) .
It is switchable...
someone know what is the use ? In what modes it is switched on? Exist a
detailed bandwidth  diagram?

Thanks for help
Giuliano I0CG
Italy
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[Bob Cunnings NW8L]

>From the K3 Owner's Manual, "Theory of Operation" section for KREF3:

"In addition to the TCXO and dividers, the KREF3 provides the 2nd transmit I.F.
mixer, which converts the DSP's 15-kHz transmit I.F. output to 8.215
MHz. This signal passes through a wide crystal filter to ensure good
rejection of the carrier and other mixer products before being routed
to the RF70 board."

Bob NW8L

On Sun, Nov 23, 2008 at 5:05 AM, Giuliano <[hidden email]> wrote:

>
> I see on the K3 KREF3 schematic a quartz filter ( 8215 KHz BW= 4 KHz) . It
> is switchable...
> someone know what is the use ? In what modes it is switched on? Exist a
> detailed bandwidth  diagram?
>
> Thanks for help
> Giuliano I0CG
> Italy
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

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