diff --git a/cmd/server/store.go b/cmd/server/store.go
index fc905f1d..52167978 100644
--- a/cmd/server/store.go
+++ b/cmd/server/store.go
@@ -176,8 +176,7 @@ type PacketStore struct {
 	// Precomputed subpath index: raw comma-joined hops → occurrence count.
 	// Built during Load(), incrementally updated on ingest. Avoids full
 	// packet iteration at query time (O(unique_subpaths) vs O(total_packets)).
-	spIndex      map[string]int        // "hop1,hop2" → count
-	spTxIndex    map[string][]*StoreTx // "hop1,hop2" → transmissions containing this subpath
+	spIndex map[string]int // "hop1,hop2" → count
 	spTotalPaths int                   // transmissions with paths >= 2 hops
 	// Precomputed distance analytics: hop distances and path totals
 	// computed during Load() and incrementally updated on ingest.
@@ -311,7 +310,7 @@ func NewPacketStore(db *DB, cfg *PacketStoreConfig, cacheTTLs ...map[string]inte
 		collisionCacheTTL: 3600 * time.Second,
 		invCooldown:       300 * time.Second,
 		spIndex:       make(map[string]int, 4096),
-		spTxIndex:     make(map[string][]*StoreTx, 4096),
+
 		advertPubkeys:   make(map[string]int),
 		lastSeenTouched: make(map[string]time.Time),
 		clockSkew:       NewClockSkewEngine(),
@@ -1537,7 +1536,7 @@ func (s *PacketStore) IngestNewFromDB(sinceID, limit int) ([]map[string]interfac
 
 	// Incrementally update precomputed subpath index with new transmissions
 	for _, tx := range broadcastTxs {
-		if addTxToSubpathIndexFull(s.spIndex, s.spTxIndex, tx) {
+		if addTxToSubpathIndex(s.spIndex, tx) {
 			s.spTotalPaths++
 		}
 		addTxToPathHopIndex(s.byPathHop, tx)
@@ -1906,7 +1905,7 @@ func (s *PacketStore) IngestNewObservations(sinceObsID, limit int) []map[string]
 				// Temporarily set parsedPath to old hops for removal.
 				saved, savedFlag := tx.parsedPath, tx.pathParsed
 				tx.parsedPath, tx.pathParsed = oldHops, true
-				if removeTxFromSubpathIndexFull(s.spIndex, s.spTxIndex, tx) {
+				if removeTxFromSubpathIndex(s.spIndex, tx) {
 					s.spTotalPaths--
 				}
 				tx.parsedPath, tx.pathParsed = saved, savedFlag
@@ -1923,7 +1922,7 @@ func (s *PacketStore) IngestNewObservations(sinceObsID, limit int) []map[string]
 			}
 			// pickBestObservation already set pathParsed=false so
 			// addTxToSubpathIndex will re-parse the new path.
-			if addTxToSubpathIndexFull(s.spIndex, s.spTxIndex, tx) {
+			if addTxToSubpathIndex(s.spIndex, tx) {
 				s.spTotalPaths++
 			}
 			addTxToPathHopIndex(s.byPathHop, tx)
@@ -2398,12 +2397,6 @@ func txGetParsedPath(tx *StoreTx) []string {
 // increments their counts in the index.  Returns true if the tx contributed
 // (path had ≥ 2 hops).
 func addTxToSubpathIndex(idx map[string]int, tx *StoreTx) bool {
-	return addTxToSubpathIndexFull(idx, nil, tx)
-}
-
-// addTxToSubpathIndexFull is like addTxToSubpathIndex but also appends
-// tx to txIdx for each subpath key (if txIdx is non-nil).
-func addTxToSubpathIndexFull(idx map[string]int, txIdx map[string][]*StoreTx, tx *StoreTx) bool {
 	hops := txGetParsedPath(tx)
 	if len(hops) < 2 {
 		return false
@@ -2413,9 +2406,6 @@ func addTxToSubpathIndexFull(idx map[string]int, txIdx map[string][]*StoreTx, tx
 		for start := 0; start <= len(hops)-l; start++ {
 			key := strings.ToLower(strings.Join(hops[start:start+l], ","))
 			idx[key]++
-			if txIdx != nil {
-				txIdx[key] = append(txIdx[key], tx)
-			}
 		}
 	}
 	return true
@@ -2425,12 +2415,6 @@ func addTxToSubpathIndexFull(idx map[string]int, txIdx map[string][]*StoreTx, tx
 // decrements counts for all raw subpaths of tx.  Returns true if the tx
 // had a path.
 func removeTxFromSubpathIndex(idx map[string]int, tx *StoreTx) bool {
-	return removeTxFromSubpathIndexFull(idx, nil, tx)
-}
-
-// removeTxFromSubpathIndexFull is like removeTxFromSubpathIndex but also
-// removes tx from txIdx for each subpath key (if txIdx is non-nil).
-func removeTxFromSubpathIndexFull(idx map[string]int, txIdx map[string][]*StoreTx, tx *StoreTx) bool {
 	hops := txGetParsedPath(tx)
 	if len(hops) < 2 {
 		return false
@@ -2443,18 +2427,6 @@ func removeTxFromSubpathIndexFull(idx map[string]int, txIdx map[string][]*StoreT
 			if idx[key] <= 0 {
 				delete(idx, key)
 			}
-			if txIdx != nil {
-				txs := txIdx[key]
-				for i, t := range txs {
-					if t == tx {
-						txIdx[key] = append(txs[:i], txs[i+1:]...)
-						break
-					}
-				}
-				if len(txIdx[key]) == 0 {
-					delete(txIdx, key)
-				}
-			}
 		}
 	}
 	return true
@@ -2464,10 +2436,9 @@ func removeTxFromSubpathIndexFull(idx map[string]int, txIdx map[string][]*StoreT
 // Must be called with s.mu held.
 func (s *PacketStore) buildSubpathIndex() {
 	s.spIndex = make(map[string]int, 4096)
-	s.spTxIndex = make(map[string][]*StoreTx, 4096)
 	s.spTotalPaths = 0
 	for _, tx := range s.packets {
-		if addTxToSubpathIndexFull(s.spIndex, s.spTxIndex, tx) {
+		if addTxToSubpathIndex(s.spIndex, tx) {
 			s.spTotalPaths++
 		}
 	}
@@ -2906,7 +2877,7 @@ func (s *PacketStore) EvictStale() int {
 		}
 
 		// Remove from subpath index
-		removeTxFromSubpathIndexFull(s.spIndex, s.spTxIndex, tx)
+		removeTxFromSubpathIndex(s.spIndex, tx)
 		// Remove from path-hop index
 		removeTxFromPathHopIndex(s.byPathHop, tx)
 	}
@@ -7078,8 +7049,27 @@ func (s *PacketStore) GetSubpathDetail(rawHops []string) map[string]interface{}
 	// Build the subpath key the same way the index does (lowercase, comma-joined)
 	spKey := strings.ToLower(strings.Join(rawHops, ","))
 
-	// Direct lookup instead of scanning all packets
-	matchedTxs := s.spTxIndex[spKey]
+	// Scan all transmissions for matching subpaths (replaces former spTxIndex
+	// lookup — the per-tx pointer index was eliminated in #791 to save ~280MB
+	// at scale). This is O(packets) but only called on drill-down, not listing.
+	var matchedTxs []*StoreTx
+	for _, tx := range s.packets {
+		hops := txGetParsedPath(tx)
+		if len(hops) < 2 {
+			continue
+		}
+		maxL := min(8, len(hops))
+		for l := 2; l <= maxL; l++ {
+			for start := 0; start <= len(hops)-l; start++ {
+				key := strings.ToLower(strings.Join(hops[start:start+l], ","))
+				if key == spKey {
+					matchedTxs = append(matchedTxs, tx)
+					goto nextTx
+				}
+			}
+		}
+	nextTx:
+	}
 
 	hourBuckets := make([]int, 24)
 	var snrSum, rssiSum float64