Changes with multiple sinks

[stephen.berger.temconsulting]

I am running the ATSC Transmitter flowgraph that is included with some GNURadio compilations.  I am connecting the output to a HackRF, using the Soapy HackRF Sink and monitoring the results on my spectrum analyzer.  I also have the QT GUI Frequency Sink connected.  When I run using either sink alone I get a nice ATSC signal either displayed or on my spectrum analyzer.  However, if I enable both sinks at the same time the waveform changes in the display and what the HackRF puts out is radically different.  Why is this?  Is there a way to have the display as a monitor and get an undistorted output from the HackRF?

 

Best Regards,

Stephen Berger

TEM Consulting, LP

Web Site - www.temconsulting.com
E-MAIL - stephen.berger@ieee.org
Phone - (512) 864-3365
Mobile - (512) 466-0833
FAX - (512) 869-8709

 

uhd_atsc_tx_v2 - HackRF.grc
Description: Binary data