diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index e69b628..7e405f8 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -1,8 +1,6 @@
 IF(SDR_WITH_QT5 AND SDR_WITH_FFTW AND SDR_WITH_PORTAUDIO)
  add_executable(sdr_spec sdr_spec.cc)
  target_link_libraries(sdr_spec ${LIBS} ${QT_LIBRARIES} libsdr libsdr-gui )
- add_executable(sdr_qrss sdr_qrss.cc)
- target_link_libraries(sdr_qrss ${LIBS} ${QT_LIBRARIES} libsdr libsdr-gui )
 ENDIF(SDR_WITH_QT5 AND SDR_WITH_FFTW AND SDR_WITH_PORTAUDIO)
 
 IF(SDR_WITH_PORTAUDIO)
diff --git a/examples/sdr_qrss.cc b/examples/sdr_qrss.cc
deleted file mode 100644
index 505d92d..0000000
--- a/examples/sdr_qrss.cc
+++ /dev/null
@@ -1,60 +0,0 @@
-#include "sdr.hh"
-#include "rtlsource.hh"
-#include "baseband.hh"
-#include "utils.hh"
-#include "gui/gui.hh"
-#include <signal.h>
-#include "portaudio.hh"
-
-#include <QApplication>
-#include <QMainWindow>
-#include <QThread>
-
-using namespace sdr;
-
-static void __sigint_handler(int signo) {
-  // On SIGINT -> stop queue properly
-  Queue::get().stop();
-}
-
-#define F_SAMPLE 11000.0
-#define B_SIZE   16384
-
-int main(int argc, char *argv[])
-{
-  Queue &queue = Queue::get();
-
-  // Register handler:
-  signal(SIGINT, __sigint_handler);
-
-  PortAudio::init();
-
-  QApplication app(argc, argv);
-
-  QMainWindow        *win       = new QMainWindow();
-  gui::Spectrum      *spec      = new gui::Spectrum(F_SAMPLE/B_SIZE, 1024, 8);
-  gui::WaterFallView *spec_view = new gui::WaterFallView(spec);
-  win->setCentralWidget(spec_view);
-  win->setMinimumSize(640, 240);
-
-  win->show();
-
-  // Assemble processing chain
-  PortSource< int16_t > src(F_SAMPLE, 2048);
-  AGC< int16_t > agc;
-
-  src.connect(&agc);
-  agc.connect(spec);
-
-  queue.addIdle(&src, &PortSource< int16_t >::next);
-
-  queue.start();
-  app.exec();
-
-  queue.stop();
-  queue.wait();
-
-  PortAudio::terminate();
-
-  return 0;
-}
diff --git a/src/gui/waterfallview.cc b/src/gui/waterfallview.cc
index 064bd4d..b8c13e6 100644
--- a/src/gui/waterfallview.cc
+++ b/src/gui/waterfallview.cc
@@ -161,8 +161,8 @@ WaterFallView::paintEvent(QPaintEvent *evt)
   QPainter painter(this);
 
   painter.save();
-  painter.setRenderHints(QPainter::SmoothPixmapTransform);
-  // Draw transformed pixmap
+  painter.setRenderHints(QPainter::SmoothPixmapTransform|QPainter::Antialiasing);
+  // Assemble trafo
   QTransform trafo;
   switch (_dir) {
   case BOTTOM_UP:
@@ -185,8 +185,14 @@ WaterFallView::paintEvent(QPaintEvent *evt)
     break;
   }
   painter.setTransform(trafo);
-
-  painter.drawPixmap(0,0, _waterfall);
+  QRect exposedRect = painter.matrix().inverted()
+      .mapRect(evt->rect())
+      .adjusted(-1, -1, 1, 1);
+  qDebug() << "Draw " << QRect(0,0,_N,_M) << " at "
+           << painter.matrix().mapRect(QRect(0,0,_N,_M));
+  // the adjust is to account for half pixels along edges
+  painter.drawPixmap(exposedRect, _waterfall, exposedRect);
+  //painter.drawPixmap(0,0, _waterfall);
   painter.restore();
 }