[Elecraft] Question on K3 Xmit and 8 MHz IF

[Joe Subich, W4TV]

Dave,

> I also played around with recording QSOs using PowerSDR but I have
> noticed that the transmit audio recorded in this manner is slightly
> off frequency. So, the receive sounds exactly on frequency but my
> transmit consistently sounds high by about 75-100 Hz. Can anybody
> explain why this is so?

Are you using default receive filter settings in the K3 or have you
adjusted high/low (shift/width)?  The K3 has the ability to adjust
the filter offset in differently transmit than in receive for proper
transmit frequency response.  If that involved offsetting the IF
center frequency slightly, it would account for the apparent "off
frequency" transmit with PowerSDR monitoring the 8.215 MHz IF.

I notice a similar effect/offset if I disconnect the P3 data cable so
the P3 display is active in both transmit and receive.

73,

    ... Joe, W4TV


On 8/22/2012 12:02 PM, Dave C wrote:
> I have a Softrock receiver connected to my K3's KXV3 IF output and have
> been using PowerSDR to provide a second receiver/panadapter.  I also played
> around with recording QSOs using PowerSDR but I have noticed that the
> transmit audio recorded in this manner is slightly off frequency.  So, the
> receive sounds exactly on frequency but my transmit consistently sounds
> high by about 75-100 Hz.  Can anybody explain why this is so?  If I listen
> on a second radio, the K3 transmit sounds fine so I think it's on frequency
> and that this little issue is some artifact of the Softrock/IF setup.
>
> Other relevant notes:  The Softrock is calibrated against WWV in the cal
> menu so it is good.  To record to a 20m USB QSO, I have the Softrock set to
> LSB with a frequency of 8.2156 MHz.  The receive is okay there but the
> transmit is off or high in pitch as noted.  I'd just like to understand why
> that is so.
>
> Thanks and 73,
>
> Dave
> K8JDC
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