diff --git a/src/decoders/trx-wspr/src/decoder.rs b/src/decoders/trx-wspr/src/decoder.rs
index 2ad8308..3df6d16 100644
--- a/src/decoders/trx-wspr/src/decoder.rs
+++ b/src/decoders/trx-wspr/src/decoder.rs
@@ -290,8 +290,8 @@ mod tests {
         let base_hz = 1496.0_f32;
         let start = EXPECTED_SIGNAL_START_SAMPLES;
 
-        for sym in 0..WSPR_SYMBOL_COUNT {
-            let tone = SYNC_VECTOR[sym] + 2 * ((sym % 2) as u8);
+        for (sym, sync_tone) in SYNC_VECTOR.iter().copied().enumerate().take(WSPR_SYMBOL_COUNT) {
+            let tone = sync_tone + 2 * ((sym % 2) as u8);
             let freq = base_hz + tone as f32 * TONE_SPACING_HZ;
             let begin = start + sym * WSPR_SYMBOL_SAMPLES;
             for i in 0..WSPR_SYMBOL_SAMPLES {
@@ -347,9 +347,8 @@ mod tests {
 
         // Generate a synthetic WSPR-like signal using the sync vector
         let mut signal = vec![0.0_f32; WSPR_SIGNAL_SAMPLES];
-        for sym in 0..WSPR_SYMBOL_COUNT {
-            let tone = SYNC_VECTOR[sym]; // just sync, no data
-            let freq = base_hz + tone as f32 * TONE_SPACING_HZ;
+        for (sym, sync_tone) in SYNC_VECTOR.iter().copied().enumerate().take(WSPR_SYMBOL_COUNT) {
+            let freq = base_hz + sync_tone as f32 * TONE_SPACING_HZ;
             let begin = sym * WSPR_SYMBOL_SAMPLES;
             for i in 0..WSPR_SYMBOL_SAMPLES {
                 let t = i as f32 / WSPR_SAMPLE_RATE as f32;
diff --git a/src/decoders/trx-wspr/src/protocol.rs b/src/decoders/trx-wspr/src/protocol.rs
index c9df2e9..428b9a9 100644
--- a/src/decoders/trx-wspr/src/protocol.rs
+++ b/src/decoders/trx-wspr/src/protocol.rs
@@ -226,6 +226,17 @@ fn unpack_message(bits: &[u8; NBITS]) -> Option<String> {
     Some(format!("{} {} {}", callsign, grid, power_dbm))
 }
 
+/// Attempt protocol-level decode from 162 4-FSK symbols.
+pub fn decode_symbols(symbols: &[u8]) -> Option<WsprProtocolMessage> {
+    if symbols.len() < NSYMS {
+        return None;
+    }
+    let coded = deinterleave(symbols);
+    let bits = fano_decode(&coded)?;
+    let message = unpack_message(&bits)?;
+    Some(WsprProtocolMessage { message })
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -285,14 +296,3 @@ mod tests {
         assert!(msg.contains("37"), "power not found in '{}'", msg);
     }
 }
-
-/// Attempt protocol-level decode from 162 4-FSK symbols.
-pub fn decode_symbols(symbols: &[u8]) -> Option<WsprProtocolMessage> {
-    if symbols.len() < NSYMS {
-        return None;
-    }
-    let coded = deinterleave(symbols);
-    let bits = fano_decode(&coded)?;
-    let message = unpack_message(&bits)?;
-    Some(WsprProtocolMessage { message })
-}