[hpsdr] 4 watts out w/ 0 mic gain

[Mike Naruta]

Thanks John.  I'm beginning to think that what I am
seeing with the scope on Janus I/Q out is just noise
way down.  It appears to be equal in both channels.
When I transmit with output, the Janus I/Q output
signal looks proper.

I can't do a transmit image rejection, because
the noise is louder than the image.

It's interesting that the 4 Watts goes to zero when
I unplug the Janus I/Q out.  I would infer that
it's coming from Janus, but all I see is that tiny
signal when looking at it with the scope.

I'm thinking that the only connection to the PC is
via the USB cable and the PC's power supply cord.
I tried bonding between the PC chassis and Atlas
ground, PC chassis to SDR-1000 ground, and Atlas
ground to SDR-1000 ground; no change.

Here is a photo of the RF output on my Kenwood RF
monitor scope.  This shows 20 meter USB with no
modulation.  The SDR-1000 reads 4 Watts Forward.
The monitor scope sweep is slightly less than 100 KHz.


Curiouser and curiouser.


Mike - AA8K



john_eckert at agilent.com wrote:
> In SSB the TX from Janus is at 0Hz, plug your headphones into the IQ out
> and take a listen. Maybe you will hear a hum, carrier, noise or one channel
> is much louder than the other indicating IQ imbalance.  Oh yea, on CW you 
> should hear a tone equal to your CW pitch setting.
> 
> I'm assumming you did the 'Transmit Rejection' cal with Janus.  The values 
> will be different than those from your sound card.
> 
> You can also put the display in scope and phase modes to look at the TX signal.
> 
> 73,
> k2ox
> 
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