From 1365b00343e42d5ec5a8611bf1a63c0d173efbed Mon Sep 17 00:00:00 2001
From: Jan Svabenik <jan@svabi.ch>
Date: Wed, 18 Mar 2026 07:28:02 +0100
Subject: [PATCH] Refine classifier rules with temporal hints

---
 internal/classifier/rules.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/internal/classifier/rules.go b/internal/classifier/rules.go
index 85b9377..4484e6c 100644
--- a/internal/classifier/rules.go
+++ b/internal/classifier/rules.go
@@ -22,6 +22,13 @@ func RuleClassify(feat Features) Classification {
 		if flat > 0.7 {
 			second = ClassNoise
 		}
+	case bw >= 2000 && bw < 3000:
+		// candidate for FT8/WSPR (very rough): low env variance, narrow BW
+		if feat.EnvVariance < 0.5 && feat.InstFreqStd < 0.7 {
+			best = ClassUnknown
+			second = ClassUnknown
+			conf = 0.5
+		}
 	case bw >= 500 && bw < 3e3:
 		if sym > 0.2 {
 			best = ClassSSBUSB