[Elecraft] K3 subrx IF out query.

[Joe Subich, W4TV]

 > However, I'm wondering if an alternative might be to duplicate the IF
 > JFET circuitry of the main RX and put it on a small perfboard inside
 > the SUBRX.  Then feed that output to a jack just like the main RX.

No reason it would not work.

 > I'd like to keep as much of the SDR spurious signals out of the K3 as
 > possible.

AS long as you were using an SDR with reasonable isolation (e.g.,
LP-Pan, SDR-IQ, P3) and *NOT* a SoftRock with its high LO leakage,
you should not have a problem putting the buffer inside the K3/KRX3.
Even then, one could use a the Clifton Labs Z10010 Bandpass filter
between the K3/KRX3 and the SDR for extra protection.

73,

    ... Joe, W4TV


On 8/17/2010 3:53 PM, Brian Alsop wrote:
> N2QT's write up on this is great
> http://groups.yahoo.com/group/Elecraft_K3/files/KRX3_IF_Out/
>
> However, I'm wondering if an alternative might be to duplicate the IF
> JFET circuitry of the main RX and put it on a small perfboard inside the
> SUBRX.  Then feed that output to a jack just like the main RX.
>
> Thinking the following components C55,C59,C68, R8,R9,R89, RFC22 and Q10
> would be all that is necessary.
>
> The Clifton labs buffer/preamp would remain outside of the K3.
>
> I'd like to keep as much of the SDR spurious signals out of the K3 as
> possible.
>
> Comments?
>
> 73 de Brian/K3KO
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