diff --git a/src/spectrum/model/tv-spectrum-transmitter.cc b/src/spectrum/model/tv-spectrum-transmitter.cc
index 956914fbe..bce9b35f3 100644
--- a/src/spectrum/model/tv-spectrum-transmitter.cc
+++ b/src/spectrum/model/tv-spectrum-transmitter.cc
@@ -53,6 +53,7 @@ TvSpectrumTransmitter::TvSpectrumTransmitter ()
     m_active (false)
 {
   NS_LOG_FUNCTION (this);
+  NS_UNUSED (m_channelNumber); // avoid unused warning; variable used by helper
 }
 
 TvSpectrumTransmitter::~TvSpectrumTransmitter ()