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Hi, I just received my SDR1000 today and have already had quite
a fun time with it. While setting it up I did find a couple of things that may
interest the group. When I did the step where you measure the output
voltage at the ‘to line out’ to set up the TX voltage level I got
zero. The tone is being routed to Out 1 and 2 of the Delta 44 instead of
3 and 4. Turn down the volume when you try this! The other thing I found is related to the manual. I
have access to a very nice spectrum analyzer so I decided to do the TX image
null. The manual says to use SSB because its ‘symmetric’,
should read ‘non-symmetric’. More importantly the tx null procedure
is incorrect in this case (SSB). The SDR1000 has a zero Hz ‘IF’
in SSB mode, therefore its image is the opposite sideband, not 20 KHz away.
With a single audio tone, say 600 Hz you want to null the other sideband 1200
Hz away. Maybe this could be stated more clearly in the next manual revision. I was able to get over 70db adjacent sideband rejection, but
when you change modes from say LSB to USB it dropped to about -50db. I
went back and forth and got them both down to -56db. 73, John k2ox |
