diff --git a/src/log.cpp b/src/log.cpp
index 29f7539..19c2333 100644
--- a/src/log.cpp
+++ b/src/log.cpp
@@ -10,6 +10,10 @@
 
 #include <pvxs/log.h>
 
+// must include before epicsStdio.h to avoid clash with printf macro
+#include <event2/util.h>
+#include <event2/buffer.h>
+
 #include <envDefs.h>
 #include <epicsAssert.h>
 #include <epicsStdio.h>
@@ -123,6 +127,47 @@ int logger_init(logger *logger)
     return logger_gbl->init(logger);
 }
 
+void xerrlogHexPrintf(const void *buf, size_t buflen,
+                      const char *fmt, ...)
+{
+    const uint8_t* const cbuf = static_cast<const uint8_t*>(buf);
+    va_list args;
+
+    // whole buffer
+    for(size_t pos=0; pos<buflen;)
+    {
+        // printed line (4 groups of 4 bytes)
+        // addr : AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
+        char buf[4][9];
+        const unsigned addr = pos;
+
+        for(unsigned grp=0; grp<4 && pos<buflen ; grp++)
+        {
+            // group of 4 hex chars
+            unsigned chr=0;
+            for(; chr<8 && pos<buflen; pos++, chr+=2)
+            {
+                static const char hex[17]="0123456789ABCDEF";
+                uint8_t v = cbuf[pos];
+                buf[grp][chr+0] = hex[(v>>4)&0xf];
+                buf[grp][chr+1] = hex[(v>>0)&0xf];
+            }
+            for(; chr<8; chr+=2)
+            {
+                buf[grp][chr+0] = '\0';
+                buf[grp][chr+1] = '\0';
+            }
+            buf[grp][8] = '\0';
+        }
+
+        errlogPrintf("%04x : %s %s %s %s\n", addr, buf[0], buf[1], buf[2], buf[3]);
+    }
+
+    va_start(args, fmt);
+    errlogVprintf(fmt, args);
+    va_end(args);
+}
+
 void logger_level_set(const char *name, int lvl)
 {
     epicsThreadOnce(&logger_once, &logger_prepare, nullptr);
diff --git a/src/pvxs/log.h b/src/pvxs/log.h
index 323285a..4f77f44 100644
--- a/src/pvxs/log.h
+++ b/src/pvxs/log.h
@@ -35,17 +35,25 @@ struct logger {
 PVXS_API int logger_init(logger *logger);
 
 static inline
-bool log_test(logger& logger, int lvl)
+bool _log_test(logger& logger, int lvl)
 {
     int cur = ::epics::atomic::get(logger.lvl);
     if(cur==-1) cur = logger_init(&logger);
     return cur>=lvl;
 }
 
+PVXS_API
+void xerrlogHexPrintf(const void *buf, size_t buflen,
+                      const char *fmt, ...) EPICS_PRINTF_STYLE(3,4);
+
+#define log_test(LOGGER, LVL) ::pvxs::_log_test(LOGGER, LVL)
+
 #define log_printf(LOGGER, LVL, ...) do{ if(log_test(LOGGER, LVL)) errlogPrintf(__VA_ARGS__); }while(0)
 
 #define log_vprintf(LOGGER, LVL, FMT, ARGS) do{ if(log_test(LOGGER, LVL)) errlogVprintf(FMT, ARGS); }while(0)
 
+#define log_hex_printf(LOGGER, LVL, BUF, BUFLEN, ...) do{ if(log_test(LOGGER, LVL)) xerrlogHexPrintf(BUF, BUFLEN, __VA_ARGS__); }while(0)
+
 //! Set level for a specific logger
 PVXS_API void logger_level_set(const char *name, int lvl);
 
diff --git a/src/udp_collector.cpp b/src/udp_collector.cpp
index 2b01894..9420a4b 100644
--- a/src/udp_collector.cpp
+++ b/src/udp_collector.cpp
@@ -77,6 +77,8 @@ struct UDPCollector : public std::enable_shared_from_this<UDPCollector>
                 return;
             }
 
+            log_hex_printf(logio, PLVL_DEBUG, &buf[0], nrx, "UDP Rx from %s", msg.src.tostring().c_str());
+
             msgs.clear();
 
             sbuf<const uint8_t> packet(&buf[0], size_t(nrx));
diff --git a/tools/pvxvct.cpp b/tools/pvxvct.cpp
index 7d434e9..853728b 100644
--- a/tools/pvxvct.cpp
+++ b/tools/pvxvct.cpp
@@ -182,7 +182,7 @@ int main(int argc, char *argv[])
         }
         if(opts.peers.empty()) {
             log_printf(out, PLVL_DEBUG, "No peer filter\n");
-        } else if(pva::log_test(out, PLVL_DEBUG)) {
+        } else if(log_test(out, PLVL_DEBUG)) {
             for(const auto& tup : opts.peers) {
                 in_addr addr, netmask;
                 std::tie(addr.s_addr, netmask.s_addr) = tup;