diff --git a/RDI_PD0_IO.pl b/RDI_PD0_IO.pl
new file mode 100644
--- /dev/null
+++ b/RDI_PD0_IO.pl
@@ -0,0 +1,967 @@
+#======================================================================
+#                    R D I _ P D 0 _ I O . P L 
+#                    doc: Sat Jan 18 14:54:43 2003
+#                    dlm: Tue Nov 26 01:29:26 2013
+#                    (c) 2003 A.M. Thurnherr
+#                    uE-Info: 873 10 NIL 0 0 72 74 2 4 NIL ofnI
+#======================================================================
+
+# Read RDI BroadBand Binary Data Files (*.[0-9][0-9][0-9])
+
+# HISTORY:
+#	Jan 18, 2003: - incepted aboard the Aurora Australis (KAOS)
+#	Jan 19, 2003: - continued
+#	Jan 20, 2003: - replaced INTENSITY by AMPLITUDE
+#	Jan 21, 2003: - changed heading-correction field names
+#	Jan 27, 2003: - cosmetics
+#	Feb 14, 2003: - moved BT setup into header
+#	Mar 15, 2003: - moved 10th xmit voltage into header as BATTERY field
+#				  - removed again, because values are not meaningful
+#	Feb 24, 2004: - continued aboard Nathaniel B. Palmer (Anslope II)
+#				  - BUG: ensemble # was wrong on error messages
+#	Feb 26, 2004: - removed ESW_ERROR and bitmasking of ERROR_STATUS_WORD
+#	Feb 27, 2004: - removed some unused (commented-out) baggage
+#	Mar 11, 2004: - BUG: renamed ACD -> ADC
+#	Mar 18, 2004: - cosmetics
+#	Mar 30, 2004: - rewrote to speed up reading; new version takes
+#					~40% less time
+#	Sep 14, 2005: - made BT data optional (NUMBER_OF_DATA_TYPES)
+#				  - added DATA_FORMAT
+#	Sep 15, 2005: - debugged
+#				  - implement checksum to robustly find EOF
+#				  - renamed to RDI_BB_Read.pl
+#				  - BUG: had used POSIX::mktime with wrong month def!
+#	Oct 30, 2005: - added WH300 FW16.27 file format
+#				  - added DATA_FORMAT_VARIANT
+#				  - changed semantics so that first valid ensemble is
+#				    in E[0] (instead of E[$ensNo-1])
+#	Nov  8, 2005: - replaced UNIXTIME by UNIX_TIME
+#				  - added SECNO
+#	Aug 31: 2006: - added DAYNO
+#	Aug  1, 2007: - BUG: typo in monthLength()
+#	Sep 18, 2007: - modified readHeader() readDta() WBRhdr() WBRens() to
+#					conserve memory (no large arrays as retvals)
+#	Jun  4, 2008: - BUG: BB150 code was not considered on Sep 18, 2007
+#	Aug 15, 2010: - downgraded "unexpected number of data types" from error to warning
+#				  - BUG: WBRcfn had not been set correctly
+#				  - modified to allow processing files without time info
+#	May 12, 2011: - added code to report built-in-test errors
+#	Mar 19, 2013: - added support for WH600 data file (58 fixed leader bytes)
+#	Mar 20, 2013: - removed DATA_FORMAT stuff
+#				  - added support for BT data in subset of ensembles
+#	Apr 29, 2013: - changed semantics to assume EOF when unexpected number of data types
+#					are present in an ensemble
+#	Nov 25, 2013: - renamed from [RDI_BB_Read.pl]
+#				  - begin implementing WBWens()
+#				  - checkEnsemble() expunged
+
+# FIRMWARE VERSIONS:
+#	It appears that different firmware versions generate different file
+#	structures. Currently (Sep 2005) these routines have been tested
+#	with the following firmware versions (as reported by [listHdr]):
+#
+#	Firmw.	DATA_FORMAT(_VARIANT)	Owner 	Cruise	FIXED_LEADER_LENGTH
+#------------------------------------------------------------
+#	05.52	BB150 (1)				UH 		CLIVAR/P16S 42
+#	16.12	WH300 (1)				FSU 	A0304		53
+#	16.21	WH300 (1)				LDEO 	NBP0402		53
+#	16.27	WH300 (2)				Nash 	?			59
+
+# NOTES:
+#	- RDI stores data in VAX/Intel byte order (little endian)
+#	- the output data structure does not exactly mirror the file data
+#	  structure; the header is not stored at all and the fixed leader
+#	  data are not duplicated in every ensemble
+#	- in the RDI files some fields that logically belong into the header
+#	  or the fixed leader (e.g. BT_MIN_CORRELATION) appear in the 
+#	  ensemble data --- these are not read on input
+#	- the field names are generally unabbreviated except for
+#	  BT (= Bottom Track), RL (= Reference Layer), MIN and MAX
+#	- all arrays are 0-referenced, but the ensemble number is not!
+#	- a list of filenames can be be passed to readData() so that
+#	  files split onto several memory cards (typically .000 .001 &c)
+#	  can be read --- not sure if this works, actually
+#	- the RDI manuals are not entirely clear everywhere; I have made
+#	  guesses in some cases, but they should not affect the main
+#	  fields of interest
+#	- some fields in the fixed leader are not really fixed in a LADCP
+#	  setting (e.g. xducer orientation); I'v made an educated guess
+#	  as to which fields to move to the ENS array
+#	- all units except pressure are SI, i.e. in m and m/s
+#	- I don't understand the ERROR_STATUS_WORD; here's what 3 different
+#	  instruments returned:
+#	  	0x88000100	FSU instrument during A0304 (Firmware 16.12)
+#		0x88008180	LDEO uplooker (slave) during NBP0402 (Firmware 16.21)
+#		0x00008180	LDEO downlooker (master) during NBP0402 (Firmware 16.21)
+#	  According to the manual (January 2001 version) this would, for example,
+#	  indicate power failures on both FSU and LDEO slave instruments...
+
+# &readData() returns perl obj (ref to anonymous hash) with the following
+# structure:
+#
+#	NUMBER_OF_DATA_TYPES			scalar		6 (no BT) or 7
+#	ENSEMBLE_BYTES					scalar		?, number of bytes w/o checksum
+#	HEADER_BYTES					scalar		?
+#	FIXED_LEADER_BYTES				scalar		42 for BB150; 53 for WH300, 58 for WH600, 59 for WH300(Nash)
+#	VARIABLE_LEADER_BYTES			scalar		?
+#	VELOCITY_DATA_BYTES				scalar		?
+#	CORRELATION_DATA_BYTES			scalar		?
+#	ECHO_INTENSITY_DATA_BYTES		scalar		?
+#	PERCENT_GOOD_DATA_BYTES			scalar		?
+#	BT_PRESENT						bool		NUMBER_OF_DATA_TYPES == 7
+#	BT_DATA_BYTES					scalar		undefined, ? if BT_PRESENT
+#	CPU_FW_VER						scalar		0--255
+#	CPU_FW_REV						scalar		0--255
+#	BEAM_FREQUENCY					scalar		75, 150, 300, 600, 1200, 2400 [kHz]
+#	CONVEX_BEAM_PATTERN				bool		undefined, 1
+#	CONCAVE_BEAM_PATTERN			bool		undefined, 1
+#	SENSOR_CONFIG					scalar		1--3
+#	XDUCER_HEAD_ATTACHED			bool		undefined, 1
+#	BEAM_ANGLE						scalar		15,20,30,undefined=other [deg]
+#	N_BEAMS							scalar		4--5
+#	N_DEMODS						scalar		2--3(???),undefined=n/a
+#	N_BINS							scalar		1--128
+#	PINGS_PER_ENSEMBLE				scalar		0--16384
+#	BIN_LENGTH						scalar		0.01--64 [m]
+#	BLANKING_DISTANCE				scalar		0-99.99 [m]
+#	MIN_CORRELATION					scalar		0--255
+#	N_CODE_REPETITIONS				scalar		0--255
+#	MIN_PERCENT_GOOD				scalar		1--100 [%]
+#	MAX_ERROR_VELOCITY				scalar		0--5 [m/s]
+#	TIME_BETWEEN_PINGS				scalar		0--? [s]
+#	BEAM_COORDINATES				bool		undefined,1
+#	INSTRUMENT_COORDINATES			bool		undefined,1
+#	SHIP_COORDINATES				bool		undefined,1
+#	EARTH_COORDINATES				bool		undefined,1
+#	PITCH_AND_ROLL_USED				bool		undefined,1
+#	USE_3_BEAM_ON_LOW_CORR			bool		undefined,1
+#	BIN_MAPPING_ALLOWED				bool		undefined,1
+#	HEADING_ALIGNMENT 				scalar		-179.99..180 [deg]
+#	HEADING_BIAS			 		scalar		-179.99..180 [deg]
+#	CALCULATE_SPEED_OF_SOUND		bool		undefined,1
+#	USE_PRESSURE_SENSOR				bool		undefined,1
+#	USE_COMPASS						bool		undefined,1
+#	USE_PITCH_SENSOR				bool		undefined,1
+#	USE_ROLL_SENSOR					bool		undefined,1
+#	USE_CONDUCTIVITY_SENSOR			bool		undefined,1
+#	USE_TEMPERATURE_SENSOR			bool		undefined,1
+#	SPEED_OF_SOUND_CALCULATED		bool		undefined,1
+#	PRESSURE_SENSOR_AVAILABLE		bool		undefined,1
+#	COMPASS_AVAILABLE				bool		undefined,1
+#	PITCH_SENSOR_AVAILABLE			bool		undefined,1
+#	ROLL_SENSOR_AVAILABLE			bool		undefined,1
+#	CONDUCTIVITY_SENSOR_AVAILABLE	bool		undefined,1
+#	TEMPERATURE_SENSOR_AVAILABLE	bool		undefined,1
+#	DISTANCE_TO_BIN1_CENTER			scalar		0--655.35 [m]
+#	TRANSMITTED_PULSE_LENGTH		scalar		0--655.35 [m]
+#	RL_FIRST_BIN					scalar		1--128
+#	RL_LAST_BIN						scalar		1--128
+#	FALSE_TARGET_THRESHOLD			scalar		0--254, undefined=disabled
+#	LOW_LATENCY_SETTING				scalar		0--5(???)
+#	TRANSMIT_LAG_DISTANCE			scalar		0--655.35 [m]
+#	CPU_SERIAL_NUMBER				scalar		undefined, 0--65535 if WH300
+#	NARROW_BANDWIDTH				bool		undefined,1 (only set if WH300)
+#	WIDE_BANDWIDTH					bool		undefined,1 (only set if WH300)
+#	TRANSMIT_POWER					scalar		undefined, 0--255(high) if WH300
+#	TRANSMIT_POWER_HIGH				bool		undefined,1 (only set if WH300)
+#	BT_PINGS_PER_ENSEMBLE			scalar		0--999
+#	BT_DELAY_BEFORE_REACQUIRE		scalar		0--999
+#	BT_MIN_CORRELATION				scalar		0--255
+#	BT_MIN_EVAL_AMPLITUDE			scalar		0--255
+#	BT_MIN_PERCENT_GOOD				scalar		0--100 [%]
+#	BT_MODE							scalar		4,5,6(?)
+#	BT_MAX_ERROR_VELOCITY			scalar		0--5 [m/s], undef=not screened
+#	BT_RL_MIN_SIZE					scalar		0--99.9 [m]
+#	BT_RL_NEAR						scalar		0--999.9 [m]
+#	BT_RL_FAR						scalar		0--999.9 [m]
+#	BT_MAX_TRACKING_DEPTH			scalar		8--999.9 [m]
+#	ENSEMBLE[ensemble_no-1]			array		ensemble info
+#		XDUCER_FACING_UP			bool		undefined, 1
+#		XDUCER_FACING_DOWN			bool		undefined, 1
+#		N_BEAMS_USED				scalar		3,4,5(?)
+#		NUMBER						scalar		1--16777215
+#		BUILT_IN_TEST_ERROR			scalar		?,undefined=none
+#		SPEED_OF_SOUND				scalar		1400--1600 [m/s]
+#		XDUCER_DEPTH				scalar		0.1--999.9 [m]
+#		HEADING						scalar		0--359.99 [deg]
+#		PITCH						scalar		-20.00-20.00 [deg]
+#		ROLL						scalar		-20.00-20.00 [deg]
+#		SALINITY					scalar		0-40 [psu]
+#		TEMPERATURE					scalar		-5.00--40.00 [deg]
+#		MIN_PRE_PING_WAIT_TIME		scalar		? [s]
+#		HEADING_STDDEV				scalar		0-180 [deg]
+#		PITCH_STDDEV				scalar		0.0-20.0 [deg]
+#		ROLL_STDDEV					scalar		0.0-20.0 [deg]
+#		ADC_XMIT_CURRENT			scalar		0--255
+#		ADC_XMIT_VOLTAGE			scalar		0--255
+#		ADC_AMBIENT_TEMPERATURE		scalar		0--255
+#		ADC_PRESSURE_PLUS			scalar		0--255
+#		ADC_PRESSURE_MINUS			scalar		0--255
+#		ADC_ATTITUDE_TEMPERATURE	scalar		0--255
+#		ADC_ATTITUDE				scalar		0--255
+#		ADC_CONTAMINATION			scalar		0--255
+#		ERROR_STATUS_WORD			scalar		undefined, ? (only set if WH300)
+#		PRESSURE					scalar		undefined, ?-? [dbar] (only set if WH300)
+#		PRESSURE_STDDEV				scalar		undefined, ?-? [dbar] (only set if WH300)
+#		DATE						string		MM/DD/YYYY
+#		YEAR						scalar		?
+#		MONTH						scalar		1--12
+#		DAY							scalar		1--31
+#		TIME						string		HH:MM:SS.hh
+#		HOUR						scalar		0--23
+#		MINUTE						scalar		0--59
+#		SECONDS						scalar		0--59.99
+#		UNIX_TIME					scalar		0--?
+#		SECNO						scalar		0--? (number of seconds since daystart)
+#		DAYNO						double		fractional day number since start of current year (1.0 is midnight Jan 1st)
+#		VELOCITY[bin][beam]			scalars		-32.767--32.768 [m/s], undef=bad
+#		CORRELATION[bin][beam]		scalars		1--255, undefined=bad
+#		ECHO_AMPLITUDE[bin][beam]	scalars		0--255
+#		PERCENT_GOOD[bin][beam]		scalars		0--255
+#		BT_RANGE[beam]				scalars		tons [m]
+#		BT_VELOCITY[beam]			scalars		see VELOCITY
+#		BT_CORRELATION[beam]		scalars		see CORRELATION
+#		BT_EVAL_AMPLITUDE[beam]		scalars		0--255
+#		BT_PERCENT_GOOD[beam]		scalars		see PERCENT_GOOD
+#		BT_RL_VELOCITY[beam]		scalars		see VELOCITY
+#		BT_RL_CORRELATION[beam]		scalars		see CORRELATION
+#		BT_RL_ECHO_AMPLITUDE[beam]	scalars		see ECHO_AMPLITUDE
+#		BT_RL_PERCENT_GOOD[beam]	scalars		see PERCENT_GOOD
+#		BT_SIGNAL_STRENGTH[beam]	scalars		0--255
+#		HIGH_GAIN					bool		1, undefined
+#		LOW_GAIN					bool		1, undefined
+
+use strict;
+use Time::Local;						# timegm()
+
+#----------------------------------------------------------------------
+# Time Conversion Subroutines
+#----------------------------------------------------------------------
+
+sub monthLength($$)										# of days in month
+{
+    my($Y,$M) = @_;
+
+    return 31 if ($M==1 || $M==3 || $M==5 || $M==7 ||
+                  $M==8 || $M==10 || $M==12);
+    return 30 if ($M==4 || $M==6 || $M==9 || $M==11);
+    return 28 if ($Y%4 != 0);
+    return 29 if ($Y%100 != 0);
+    return 28 if ($Y%400 > 0);
+    return 29;
+}
+
+{ my($epoch,$lM,$lD,$lY,$ldn);							# static scope
+
+  sub dayNo($$$$$$)
+  {
+	  my($Y,$M,$D,$h,$m,$s) = @_;
+	  my($dn);
+  
+	  if ($Y==$lY && $M==$lM && $D==$lD) {				# same day as last samp
+		  $dn = $ldn;
+	  } else {											# new day
+		  $epoch = $Y unless defined($epoch);			# 1st call
+		  $lY = $Y; $lM = $M; $lD = $D;					# store
+  
+		  for ($dn=0,my($cY)=$epoch; $cY<$Y; $cY++) {	# multiple years
+			  $dn += 337 + &monthLength($Y,$M);
+		  }
+  
+		  $dn += $D;									# day in month
+		  while (--$M > 0) {							# preceding months
+			  $dn += &monthLength($Y,$M);
+		  }
+
+		  $ldn = $dn;									# store
+	  }
+	  return $dn + $h/24 + $m/24/60 + $s/24/3600;
+  }
+
+} # static scope
+
+#----------------------------------------------------------------------
+# Read Data
+#----------------------------------------------------------------------
+
+my($WBRcfn,$WBPcfn);									# current file names for reading/patching
+my($BIT_errors) = 0;									# built-in-test errors
+
+my($FmtErr) = "%s: illegal %s Id 0x%04x at ensemble %d";
+
+#----------------------------------------------------------------------
+# readHeader(file_name,^dta) WBRhdr(^data)
+#	- read header data
+#	- also includes some data from 1st ens
+#----------------------------------------------------------------------
+
+sub readHeader(@)
+{
+	my($fn,$dta) = @_;
+	$WBRcfn = $fn;
+    open(WBRF,$WBRcfn) || die("$WBRcfn: $!");
+    WBRhdr($dta);    
+}
+
+sub WBRhdr($)
+{
+	my($dta) = @_;
+	my($buf,$hid,$did,$Ndt,$B,$W,$i,$dummy,$id,@WBRofs);
+	my($B1,$B2,$B3,$B4,$B5,$B6,$B7,$W1,$W2,$W3,$W4,$W5);
+	
+	#--------------------
+	# HEADER
+	#--------------------
+
+	sysread(WBRF,$buf,6) == 6 || die("$WBRcfn: $!");
+	($hid,$did,$dta->{ENSEMBLE_BYTES},$dummy,$dta->{NUMBER_OF_DATA_TYPES})
+		= unpack('CCvCC',$buf);
+	$hid == 0x7f || die(sprintf($FmtErr,$WBRcfn,"Header",$hid,0));
+	$did == 0x7f || die(sprintf($FmtErr,$WBRcfn,"Data Source",$did,0));
+	printf(STDERR "\n$WBRcfn: WARNING: unexpected number of data types (%d)\n",
+		$dta->{NUMBER_OF_DATA_TYPES})
+			unless ($dta->{NUMBER_OF_DATA_TYPES} == 6 ||
+					$dta->{NUMBER_OF_DATA_TYPES} == 7);
+	$dta->{BT_PRESENT} = ($dta->{NUMBER_OF_DATA_TYPES} == 7);
+					  
+	sysread(WBRF,$buf,2*$dta->{NUMBER_OF_DATA_TYPES})
+		== 2*$dta->{NUMBER_OF_DATA_TYPES}
+			|| die("$WBRcfn: $!");
+	@WBRofs = unpack("v$dta->{NUMBER_OF_DATA_TYPES}",$buf);
+
+	$dta->{HEADER_BYTES} 					= $WBRofs[0];
+	$dta->{FIXED_LEADER_BYTES} 				= $WBRofs[1] - $WBRofs[0];
+	$dta->{VARIABLE_LEADER_BYTES}			= $WBRofs[2] - $WBRofs[1];
+	$dta->{VELOCITY_DATA_BYTES}				= $WBRofs[3] - $WBRofs[2];
+	$dta->{CORRELATION_DATA_BYTES}			= $WBRofs[4] - $WBRofs[3];
+	$dta->{ECHO_INTENSITY_DATA_BYTES}		= $WBRofs[5] - $WBRofs[4];
+	if ($dta->{BT_PRESENT}) {
+		$dta->{PERCENT_GOOD_DATA_BYTES}		= $WBRofs[6] - $WBRofs[5];
+		$dta->{BT_DATA_BYTES}				= $dta->{ENSEMBLE_BYTES} - 4 - $WBRofs[6];
+	} else {
+		$dta->{PERCENT_GOOD_DATA_BYTES}		= $dta->{ENSEMBLE_BYTES} - 4 - $WBRofs[5];
+	}
+
+	if ($dta->{FIXED_LEADER_BYTES} == 42) {				# Eric Firing's old instrument I used in 2004
+		$dta->{INSTRUMENT_TYPE} = 'BB150';
+	} elsif ($dta->{FIXED_LEADER_BYTES} == 53) {		# old firmware: no serial numbers
+		$dta->{INSTRUMENT_TYPE} = 'Workhorse';	
+	} elsif ($dta->{FIXED_LEADER_BYTES} == 59) {		# new firmware: with serial numbers
+		$dta->{INSTRUMENT_TYPE} = 'Workhorse';
+    } elsif ($dta->{FIXED_LEADER_BYTES} == 58) {		# DVL
+		$dta->{INSTRUMENT_TYPE} = 'Explorer';
+    } 
+
+#	for ($i=0; $i<$dta->{NUMBER_OF_DATA_TYPES}; $i++) {
+#		printf(STDERR "\nWBRofs[$i] = %d",$WBRofs[$i]);
+#	}
+
+	#----------------------------------
+	# Check Data Format of 1st Ensemble
+	#----------------------------------
+
+	sysseek(WBRF,$WBRofs[1],0) || die("$WBRcfn: $!");
+	sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+	$id = unpack('v',$buf);
+	$id == 0x0080 || die(sprintf($FmtErr,$WBRcfn,"Variable Leader",$id,1));
+
+	sysseek(WBRF,$WBRofs[2],0) || die("$WBRcfn: $!");
+	sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+	$id = unpack('v',$buf);
+	$id == 0x0100 || die(sprintf($FmtErr,$WBRcfn,"Velocity Data",$id,1));
+
+	sysseek(WBRF,$WBRofs[3],0) || die("$WBRcfn: $!");
+	sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+	$id = unpack('v',$buf);
+	$id == 0x0200 || die(sprintf($FmtErr,$WBRcfn,"Correlation Data",$id,1));
+    
+	sysseek(WBRF,$WBRofs[4],0) || die("$WBRcfn: $!");
+	sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+	$id = unpack('v',$buf);
+	$id == 0x0300 || die(sprintf($FmtErr,$WBRcfn,"Echo Intensity",$id,1));
+
+	sysseek(WBRF,$WBRofs[5],0) || die("$WBRcfn: $!");
+	sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+	$id = unpack('v',$buf);
+	$id == 0x0400 || die(sprintf($FmtErr,$WBRcfn,"Percent-Good Data",$id,1));
+
+	if ($dta->{BT_PRESENT}) {
+		sysseek(WBRF,$WBRofs[6],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+		$id = unpack('v',$buf);
+		$id == 0x0600 || die(sprintf($FmtErr,$WBRcfn,"Bottom Track",$id,1));
+    }
+
+	#--------------------
+	# FIXED LEADER
+	#--------------------
+
+	sysseek(WBRF,$WBRofs[0],0) || die("$WBRcfn: $!");
+	sysread(WBRF,$buf,42) == 42 || die("$WBRcfn: $!");
+	($id,$dta->{CPU_FW_VER},$dta->{CPU_FW_REV},$B1,$B2,$dummy,$dummy,$dummy,
+	 $dta->{N_BINS},$dta->{PINGS_PER_ENSEMBLE},$dta->{BIN_LENGTH},
+	 $dta->{BLANKING_DISTANCE},$dummy,$dta->{MIN_CORRELATION},
+	 $dta->{N_CODE_REPETITIONS},$dta->{MIN_PERCENT_GOOD},
+	 $dta->{MAX_ERROR_VELOCITY},$dta->{TIME_BETWEEN_PINGS},$B3,$B4,$B5,
+	 $dta->{HEADING_ALIGNMENT},$dta->{HEADING_BIAS},$B6,$B7,
+	 $dta->{DISTANCE_TO_BIN1_CENTER},$dta->{TRANSMITTED_PULSE_LENGTH},
+	 $dta->{REF_LAYER_FIRST_BIN},$dta->{REF_LAYER_LAST_BIN},
+	 $dta->{FALSE_TARGET_THRESHOLD},$dta->{LOW_LATENCY_SETTING},
+	 $dta->{TRANSMIT_LAG_DISTANCE}) =
+		unpack('vCCCCC3CvvvCCCCvCCCCvvCCvvCCCCv',$buf);
+
+	$id == 0x0000 || die(sprintf($FmtErr,$WBRcfn,"Fixed Leader",$id,0));
+
+    $dta->{BEAM_FREQUENCY} = 2**($B1 & 0x07) * 75;
+    $dta->{CONVEX_BEAM_PATTERN} = 1 if ($B1 & 0x08);
+    $dta->{CONCAVE_BEAM_PATTERN} = 1 if (!($B1 & 0x08));
+    $dta->{SENSOR_CONFIG} = ($B1 & 0x30) >> 4;
+    $dta->{XDUCER_HEAD_ATTACHED} = 1 if ($B1 & 0x40);
+
+	if	  (($B2 & 0x03) == 0x00) { $dta->{BEAM_ANGLE} = 15; }
+	elsif (($B2 & 0x03) == 0x01) { $dta->{BEAM_ANGLE} = 20; }
+	elsif (($B2 & 0x03) == 0x02) { $dta->{BEAM_ANGLE} = 30; }
+	if	  (($B2 & 0xF0) == 0x40) { $dta->{N_BEAMS} = 4; }
+	elsif (($B2 & 0xF0) == 0x50) { $dta->{N_BEAMS} = 5; $dta->{N_DEMODS} = 3; }
+    elsif (($B2 & 0xF0) == 0xF0) { $dta->{N_BEAMS} = 5; $dta->{N_DEMODS} = 2; }
+    
+    $dta->{BIN_LENGTH} /= 100;
+    $dta->{BLANKING_DISTANCE} /= 100;
+
+    $dta->{MAX_ERROR_VELOCITY} /= 1000;
+    $dta->{TIME_BETWEEN_PINGS} *= 60;
+	$dta->{TIME_BETWEEN_PINGS} += $B3 + $B4/100;
+
+	$dta->{BEAM_COORDINATES}		  = 1 if (($B5 & 0x18) == 0x00);
+	$dta->{INSTRUMENT_COORDINATES}	  = 1 if (($B5 & 0x18) == 0x08);
+	$dta->{SHIP_COORDINATES}		  = 1 if (($B5 & 0x18) == 0x10);
+	$dta->{EARTH_COORDINATES}		  = 1 if (($B5 & 0x18) == 0x18);
+	$dta->{PITCH_AND_ROLL_USED} 	  = 1 if ($B5 & 0x04);
+	$dta->{USE_3_BEAM_ON_LOW_CORR}	  = 1 if ($B5 & 0x02);
+    $dta->{BIN_MAPPING_ALLOWED}       = 1 if ($B5 & 0x01);
+        
+	$dta->{HEADING_ALIGNMENT} =
+		($dta->{EARTH_COORDINATES} || $dta->{SHIP_COORDINATES}) ?
+			$dta->{HEADING_ALIGNMENT} / 100 : undef;
+	$dta->{HEADING_BIAS} =
+		($dta->{EARTH_COORDINATES} || $dta->{SHIP_COORDINATES}) ?
+			$dta->{HEADING_BIAS} / 100 : undef;
+
+	$dta->{CALCULATE_SPEED_OF_SOUND}  = 1 if ($B6 & 0x40); 
+	$dta->{USE_PRESSURE_SENSOR} 	  = 1 if ($B6 & 0x20); 
+	$dta->{USE_COMPASS} 			  = 1 if ($B6 & 0x10); 
+	$dta->{USE_PITCH_SENSOR}		  = 1 if ($B6 & 0x08); 
+	$dta->{USE_ROLL_SENSOR} 		  = 1 if ($B6 & 0x04); 
+	$dta->{USE_CONDUCTIVITY_SENSOR}   = 1 if ($B6 & 0x02); 
+    $dta->{USE_TEMPERATURE_SENSOR}    = 1 if ($B6 & 0x01); 
+
+	$dta->{SPEED_OF_SOUND_CALCULATED}	  = 1 if ($B7 & 0x40); 
+	$dta->{PRESSURE_SENSOR_AVAILABLE}	  = 1 if ($B7 & 0x20); 
+	$dta->{COMPASS_AVAILABLE}			  = 1 if ($B7 & 0x10); 
+	$dta->{PITCH_SENSOR_AVAILABLE}		  = 1 if ($B7 & 0x08); 
+	$dta->{ROLL_SENSOR_AVAILABLE}		  = 1 if ($B7 & 0x04); 
+	$dta->{CONDUCTIVITY_SENSOR_AVAILABLE} = 1 if ($B7 & 0x02); 
+    $dta->{TEMPERATURE_SENSOR_AVAILABLE}  = 1 if ($B7 & 0x01); 
+
+    $dta->{DISTANCE_TO_BIN1_CENTER}  /= 100;
+    $dta->{TRANSMITTED_PULSE_LENGTH} /= 100;
+
+    $dta->{FALSE_TARGET_THRESHOLD} = undef
+		if ($dta->{FALSE_TARGET_THRESHOLD} == 255);
+    $dta->{TRANSMIT_LAG_DISTANCE} /= 100;
+
+	if ($dta->{INSTRUMENT_TYPE} eq 'Workhorse') {
+		sysread(WBRF,$buf,11) == 11 || die("$WBRcfn: $!");
+		($W1,$W2,$W3,$W4,$W5,$dta->{TRANSMIT_POWER}) = 
+			unpack('vvvvvC',$buf);
+
+		$dta->{CPU_SERIAL_NUMBER} = sprintf("%04X%04X%04X%04X",$W1,$W2,$W3,$W4);
+	
+		$dta->{NARROW_BANDWIDTH} = ($W5 == 1);
+		$dta->{WIDE_BANDWIDTH}	 = ($W5 == 0);
+	    $dta->{TRANSMIT_POWER_HIGH} = ($dta->{TRANSMIT_POWER} == 255);
+
+		if ($dta->{FIXED_LEADER_BYTES} == 59) {					# new style with serial number
+			sysread(WBRF,$buf,6) == 6 || die("$WBRcfn: $!");
+			($dummy,$dta->{SERIAL_NUMBER},$dummy) =				# last bytes is beam angle, but that info has
+				unpack('CVC',$buf);								# already been provided above
+		}
+    }
+
+	if ($dta->{INSTRUMENT_TYPE} eq 'Explorer') {
+		sysread(WBRF,$buf,16) == 16 || die("$WBRcfn: $!");
+		($dummy,$dummy,$W5,$dummy,$dta->{SERIAL_NUMBER}) = 
+			unpack('VVvvV',$buf);
+		$dta->{NARROW_BANDWIDTH} = ($W5 == 1);
+		$dta->{WIDE_BANDWIDTH}	 = ($W5 == 0);
+    }
+
+	#-----------------------
+	# 1st ENSEMBLE, BT Setup
+	#-----------------------
+
+	if ($dta->{BT_PRESENT}) {
+		sysseek(WBRF,$WBRofs[6],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,12) == 12 || die("$WBRcfn: $!");
+		($id,$dta->{BT_PINGS_PER_ENSEMBLE},$dta->{BT_DELAY_BEFORE_REACQUIRE},
+		 $dta->{BT_MIN_CORRELATION},$dta->{BT_MIN_EVAL_AMPLITUDE},
+		 $dta->{BT_MIN_PERCENT_GOOD},$dta->{BT_MODE},
+		 $dta->{BT_MAX_ERROR_VELOCITY}) = unpack('vvvCCCCv',$buf);
+		 
+		$id == 0x0600 ||
+			die(sprintf($FmtErr,$WBRcfn,"Bottom Track",$id,0,tell(WBRF)));
+	
+		$dta->{BT_MAX_ERROR_VELOCITY} =
+			$dta->{BT_MAX_ERROR_VELOCITY} ? $dta->{BT_MAX_ERROR_VELOCITY} / 1000
+										  : undef;
+	
+		sysseek(WBRF,28,1) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,6) == 6 || die("$WBRcfn: $!");
+		($dta->{BT_RL_MIN_SIZE},$dta->{BT_RL_NEAR},$dta->{BT_RL_FAR})
+			= unpack('vvv',$buf);
+	
+		$dta->{BT_RL_MIN_SIZE} /= 10;
+		$dta->{BT_RL_NEAR} /= 10;
+		$dta->{BT_RL_FAR} /= 10;
+	    
+		sysseek(WBRF,20,1) || die("$WBRcfn: $!");		# skip data
+		sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+	    $dta->{BT_MAX_TRACKING_DEPTH} = unpack('v',$buf) / 10;
+    }
+    
+    return $dta;
+}
+
+#----------------------------------------------------------------------
+# readData(file_name,^data) WBRens(nbins,fixed_leader_bytes,^data)
+# 	- read all ensembles
+#----------------------------------------------------------------------
+
+sub readData(@)
+{
+	my($fn,$dta) = @_;
+	$WBRcfn = $fn;
+    open(WBRF,$WBRcfn) || die("$WBRcfn: $!");
+    WBRhdr($dta);
+	WBRens($dta->{N_BINS},$dta->{FIXED_LEADER_BYTES},
+		   \@{$dta->{ENSEMBLE}});
+	print(STDERR "$WBRcfn: $BIT_errors built-in-test errors\n")
+		if ($BIT_errors);
+}
+
+sub WBRens($$$)
+{
+	my($nbins,$fixed_leader_bytes,$E) = @_;
+	my($start_ens,$B1,$B2,$B3,$B4,$I,$id,$bin,$beam,$buf,$dummy,@dta,$i,$cs,@WBRofs);
+	my($ens,$ensNo,$dayStart,$ens_length,$BT_present,$hid,$did,$ndt);
+
+	for ($ens=$start_ens=0; 1; $ens++,$start_ens+=$ens_length+2) {
+#		print(STDERR "ens = $ens\n");
+#		print(STDERR "start_ens = $start_ens\n");
+
+		#----------------------------------------
+		# Get ensemble length and # of data types 
+		#----------------------------------------
+
+		sysseek(WBRF,$start_ens,0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,6) == 6 || last;
+		($hid,$did,$ens_length,$dummy,$ndt) = unpack('CCvCC',$buf);
+		$hid == 0x7f || die(sprintf($FmtErr,$WBRcfn,"Header",$hid,0));
+		$did == 0x7f || die(sprintf($FmtErr,$WBRcfn,"Data Source",$did,0));
+		printf(STDERR "\n$WBRcfn: WARNING: unexpected number of data types (%d, ens=$ens)\n",$ndt),last
+				unless ($ndt == 6 || $ndt == 7);
+		$BT_present = ($ndt == 7);
+		sysread(WBRF,$buf,2*$ndt) == 2*$ndt || die("$WBRcfn: $!");
+		@WBRofs = unpack("v$ndt",$buf);
+		$fixed_leader_bytes = $WBRofs[1] - $WBRofs[0];
+#		print(STDERR "@WBRofs\n");
+	
+		#-------------------------------
+		# Make Sure Ensemble is Complete
+		#-------------------------------
+
+		# UH BB150 writes incomplete ensembles (i.e. short read
+		# indicates EOF). FSU WH300 has bogus data in incomplete
+		# final ensemble.
+
+		sysseek(WBRF,$start_ens,0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,$ens_length) == $ens_length || last;
+
+		sysread(WBRF,$cs,2) == 2 || last;
+		last unless (unpack('%16C*',$buf) == unpack('v',$cs));
+
+		#------------------------------
+		# Variable Leader
+		#------------------------------
+	
+		sysseek(WBRF,$start_ens+$WBRofs[1],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,4) == 4 || die("$WBRcfn: $!");
+		($id,$ensNo) = unpack("vv",$buf);
+
+		$id == 0x0080 ||
+			die(sprintf($FmtErr,$WBRcfn,"Variable Leader",$id,$ensNo+1));
+
+		if ($fixed_leader_bytes==42 || $fixed_leader_bytes==58) {			# BB150 & Explorer DVL
+			sysread(WBRF,$buf,7) == 7 || die("$WBRcfn: $!");
+			(${$E}[$ens]->{YEAR},${$E}[$ens]->{MONTH},
+			 ${$E}[$ens]->{DAY},${$E}[$ens]->{HOUR},${$E}[$ens]->{MINUTE},
+			 ${$E}[$ens]->{SECONDS},$B4) = unpack('CCCCCCC',$buf);
+			${$E}[$ens]->{SECONDS} += $B4/100;
+			${$E}[$ens]->{YEAR} += (${$E}[$ens]->{YEAR} > 80) ? 1900 : 2000;
+		} else {
+			sysseek(WBRF,7,1) || die("$WBRcfn: $!");							# use Y2K RTC instead
+		}
+
+		sysread(WBRF,$buf,1) == 1 || die("$WBRcfn: $!");
+		$ensNo += unpack('C',$buf) << 16;
+		${$E}[$ens]->{NUMBER} = $ensNo;
+		
+		sysread(WBRF,$buf,30) == 30 || die("$WBRcfn: $!");
+		(${$E}[$ens]->{BUILT_IN_TEST_ERROR},${$E}[$ens]->{SPEED_OF_SOUND},
+		 ${$E}[$ens]->{XDUCER_DEPTH},${$E}[$ens]->{HEADING},
+		 ${$E}[$ens]->{PITCH},${$E}[$ens]->{ROLL},
+		 ${$E}[$ens]->{SALINITY},${$E}[$ens]->{TEMPERATURE},
+		 ${$E}[$ens]->{MIN_PRE_PING_WAIT_TIME},$B1,$B2,
+		 ${$E}[$ens]->{HEADING_STDDEV},${$E}[$ens]->{PITCH_STDDEV},
+		 ${$E}[$ens]->{ROLL_STDDEV},${$E}[$ens]->{ADC_XMIT_CURRENT},
+		 ${$E}[$ens]->{ADC_XMIT_VOLTAGE},${$E}[$ens]->{ADC_AMBIENT_TEMPERATURE},
+		 ${$E}[$ens]->{ADC_PRESSURE_PLUS},${$E}[$ens]->{ADC_PRESSURE_MINUS},
+		 ${$E}[$ens]->{ADC_ATTITUDE_TEMPERATURE},${$E}[$ens]->{ADC_ATTITUDE},
+		 ${$E}[$ens]->{ADC_CONTAMINATION})
+			= unpack('vvvvvvvvCCCCCCCCCCCCCC',$buf);
+
+		${$E}[$ens]->{BUILT_IN_TEST_ERROR} = undef
+			unless (${$E}[$ens]->{BUILT_IN_TEST_ERROR});
+		$BIT_errors++ if (${$E}[$ens]->{BUILT_IN_TEST_ERROR});
+
+		${$E}[$ens]->{XDUCER_DEPTH} /= 10;
+		${$E}[$ens]->{HEADING} /= 100;
+		${$E}[$ens]->{PITCH} = unpack('s',pack('S',${$E}[$ens]->{PITCH})) / 100;
+		${$E}[$ens]->{ROLL}  = unpack('s',pack('S',${$E}[$ens]->{ROLL})) / 100;
+		${$E}[$ens]->{TEMPERATURE} =
+			unpack('s',pack('S',${$E}[$ens]->{TEMPERATURE})) / 100;
+		${$E}[$ens]->{MIN_PRE_PING_WAIT_TIME} *= 60;
+		${$E}[$ens]->{MIN_PRE_PING_WAIT_TIME} += $B1 + $B2/100;
+		${$E}[$ens]->{PITCH_STDDEV} /= 10;
+		${$E}[$ens]->{ROLL_STDDEV} /= 10;
+
+		if ($fixed_leader_bytes==53 || $fixed_leader_bytes==59) {			# Workhorse instruments
+			sysread(WBRF,$buf,23) == 23 || die("$WBRcfn: $!");
+			(${$E}[$ens]->{ERROR_STATUS_WORD},
+		 	 $dummy,${$E}[$ens]->{PRESSURE},${$E}[$ens]->{PRESSURE_STDDEV},
+			 $dummy,${$E}[$ens]->{YEAR},$B3,${$E}[$ens]->{MONTH},
+			 ${$E}[$ens]->{DAY},${$E}[$ens]->{HOUR},${$E}[$ens]->{MINUTE},
+			 ${$E}[$ens]->{SECONDS},$B4)
+				= unpack('VvVVCCCCCCCCC',$buf);
+
+			${$E}[$ens]->{PRESSURE} /= 1000;
+			${$E}[$ens]->{PRESSURE_STDDEV} /= 1000;
+			${$E}[$ens]->{YEAR} *= 100; ${$E}[$ens]->{YEAR} += $B3;
+			${$E}[$ens]->{SECONDS} += $B4/100;
+		}
+
+		if ($fixed_leader_bytes == 58) {									# Explorer DVL
+			sysread(WBRF,$buf,14) == 14 || die("$WBRcfn: $!");
+			(${$E}[$ens]->{ERROR_STATUS_WORD},
+		 	 $dummy,${$E}[$ens]->{PRESSURE},${$E}[$ens]->{PRESSURE_STDDEV})
+				= unpack('VvVV',$buf);
+			${$E}[$ens]->{PRESSURE} /= 1000;
+			${$E}[$ens]->{PRESSURE_STDDEV} /= 1000;
+		}
+		
+		${$E}[$ens]->{DATE}
+			= sprintf("%02d/%02d/%d",${$E}[$ens]->{MONTH},
+									 ${$E}[$ens]->{DAY},
+									 ${$E}[$ens]->{YEAR});
+		${$E}[$ens]->{TIME}
+			= sprintf("%02d:%02d:%05.02f",${$E}[$ens]->{HOUR},
+										  ${$E}[$ens]->{MINUTE},
+									 	  ${$E}[$ens]->{SECONDS});
+		${$E}[$ens]->{DAYNO}
+			= &dayNo(${$E}[$ens]->{YEAR},${$E}[$ens]->{MONTH},${$E}[$ens]->{DAY},
+					 ${$E}[$ens]->{HOUR},${$E}[$ens]->{MINUTE},${$E}[$ens]->{SECONDS});
+
+		# when analyzing an STA file from an OS75 SADCP (Poseidion),
+		# I noticed that there is no time information. This causes
+		# timegm to bomb. 
+		if (${$E}[$ens]->{MONTH} == 0) {					# no time info
+			${$E}[$ens]->{UNIX_TIME} = 0;
+			${$E}[$ens]->{SECNO} = 0;
+        } else {
+			${$E}[$ens]->{UNIX_TIME}
+				= timegm(0,${$E}[$ens]->{MINUTE},
+						   ${$E}[$ens]->{HOUR},
+						   ${$E}[$ens]->{DAY},
+						   ${$E}[$ens]->{MONTH}-1,			# timegm jan==0!!!
+						   ${$E}[$ens]->{YEAR})
+				  + ${$E}[$ens]->{SECONDS};
+	
+			$dayStart = timegm(0,0,0,${$E}[$ens]->{DAY},
+									 ${$E}[$ens]->{MONTH}-1,
+									 ${$E}[$ens]->{YEAR})
+				unless defined($dayStart);
+	        ${$E}[$ens]->{SECNO} = ${$E}[$ens]->{UNIX_TIME} - $dayStart;
+        }
+
+		sysseek(WBRF,$start_ens+$WBRofs[0]+4,0)		# System Config / Fixed Leader
+			|| die("$WBRcfn: $!");
+
+		sysread(WBRF,$buf,5) == 5 || die("$WBRcfn: $!");
+		($B1,$dummy,$dummy,$dummy,${$E}[$ens]->{N_BEAMS_USED})
+			= unpack('CCCCC',$buf);		
+		${$E}[$ens]->{XDUCER_FACING_UP}   = 1 if     ($B1 & 0x80);
+		${$E}[$ens]->{XDUCER_FACING_DOWN} = 1 unless ($B1 & 0x80);
+
+		#--------------------
+		# Velocity Data
+		#--------------------
+
+		my($ndata) = $nbins * 4;
+
+		sysseek(WBRF,$start_ens+$WBRofs[2],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,2+$ndata*2) == 2+$ndata*2 || die("$WBRcfn: $!");
+		($id,@dta) = unpack("vv$ndata",$buf);
+
+		$id == 0x0100 ||
+			die(sprintf($FmtErr,$WBRcfn,"Velocity Data",$id,$ens));
+		
+		for ($i=0,$bin=0; $bin<$nbins; $bin++) {
+			for ($beam=0; $beam<4; $beam++,$i++) {
+				${$E}[$ens]->{VELOCITY}[$bin][$beam] =
+					unpack('s',pack('S',$dta[$i])) / 1000
+						if ($dta[$i] != 0x8000);
+			}
+		}
+
+		#--------------------
+		# Correlation Data
+		#--------------------
+
+		sysseek(WBRF,$start_ens+$WBRofs[3],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,2+$ndata) == 2+$ndata || die("$WBRcfn: $!");
+		($id,@dta) = unpack("vC$ndata",$buf);
+
+		$id == 0x0200 ||
+			die(sprintf($FmtErr,$WBRcfn,"Correlation Data",$id,$ens));
+		
+		for ($i=0,$bin=0; $bin<$nbins; $bin++) {
+			for ($beam=0; $beam<4; $beam++,$i++) {
+				${$E}[$ens]->{CORRELATION}[$bin][$beam] = $dta[$i]
+					if ($dta[$i]);
+			}
+		}
+
+		#--------------------
+		# Echo Intensity Data
+		#--------------------
+
+		sysseek(WBRF,$start_ens+$WBRofs[4],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,2+$ndata) == 2+$ndata || die("$WBRcfn: $!");
+		($id,@dta) = unpack("vC$ndata",$buf);
+
+		$id == 0x0300 ||
+			die(sprintf($FmtErr,$WBRcfn,"Echo Intensity",$id,$ens));
+
+		for ($i=0,$bin=0; $bin<$nbins; $bin++) {
+			for ($beam=0; $beam<4; $beam++,$i++) {
+				${$E}[$ens]->{ECHO_AMPLITUDE}[$bin][$beam] = $dta[$i];
+			}
+		}
+
+		#--------------------
+		# Percent Good Data
+		#--------------------
+
+		sysseek(WBRF,$start_ens+$WBRofs[5],0) || die("$WBRcfn: $!");
+		sysread(WBRF,$buf,2+$ndata) == 2+$ndata || die("$WBRcfn: $!");
+		($id,@dta) = unpack("vC$ndata",$buf);
+
+		$id == 0x0400 ||
+			die(sprintf($FmtErr,$WBRcfn,"Percent-Good Data",$id,$ens));
+
+		for ($i=0,$bin=0; $bin<$nbins; $bin++) {
+			for ($beam=0; $beam<4; $beam++,$i++) {
+				${$E}[$ens]->{PERCENT_GOOD}[$bin][$beam] = $dta[$i];
+			}
+		}
+
+		#--------------------
+		# Bottom-Track Data
+		#--------------------
+
+		if ($BT_present) {
+			sysseek(WBRF,$start_ens+$WBRofs[6],0) || die("$WBRcfn: $!");
+			sysread(WBRF,$buf,2) == 2 || die("$WBRcfn: $!");
+			$id = unpack('v',$buf);
+	
+			$id == 0x0600 ||
+				die(sprintf($FmtErr,$WBRcfn,"Bottom Track",$id,$ens));
+	
+			sysseek(WBRF,14,1) || die("$WBRcfn: $!");		# BT config
+	
+			sysread(WBRF,$buf,28) == 28 || die("$WBRcfn: $!");
+			@dta = unpack('v4v4C4C4C4',$buf);
+		    
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_RANGE}[$beam] = $dta[$beam] / 100
+						if ($dta[$beam]);
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_VELOCITY}[$beam] =
+					unpack('s',pack('S',$dta[4+$beam])) / 1000
+						if ($dta[4+$beam] != 0x8000);
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_CORRELATION}[$beam] = $dta[8+$beam]
+					if ($dta[8+$beam]);
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_EVAL_AMPLITUDE}[$beam] = $dta[12+$beam];
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_PERCENT_GOOD}[$beam] = $dta[16+$beam];
+			}
+	
+			sysseek(WBRF,6,1) || die("$WBRcfn: $!");		# BT config
+	
+			sysread(WBRF,$buf,20) == 20 || die("$WBRcfn: $!");
+			@dta = unpack('v4C4C4C4',$buf);
+	
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_RL_VELOCITY}[$beam] =
+					unpack('s',pack('S',$dta[$beam])) / 1000
+						if ($dta[$beam] != 0x8000);
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_RL_CORRELATION}[$beam] = $dta[4+$beam]
+					if ($dta[4+$beam]);
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_RL_ECHO_AMPLITUDE}[$beam] = $dta[8+$beam];
+			}
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_RL_PERCENT_GOOD}[$beam] = $dta[12+$beam];
+			}
+	
+			sysseek(WBRF,2,1) || die("$WBRcfn: $!");		# BT config
+	
+			sysread(WBRF,$buf,9) == 9 || die("$WBRcfn: $!");
+			@dta = unpack('C4CC4',$buf);
+	
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_SIGNAL_STRENGTH}[$beam] = $dta[$beam];
+			}
+			${$E}[$ens]->{HIGH_GAIN} if	   ($dta[4]);
+			${$E}[$ens]->{LOW_GAIN}	unless ($dta[4]);
+			for ($beam=0; $beam<4; $beam++) {
+				${$E}[$ens]->{BT_RANGE}[$beam] += $dta[5+$beam] * 655.36
+					if ($dta[5+$beam]);
+	        }
+	    } # BT present
+	} # ens loop
+}
+
+#----------------------------------------------------------------------
+# WBPens(nbins,fixed_leader_bytes,^data)
+# 	- patch PD0 file with new data
+#	- file must already exist and have correct structure
+#	- currently only does part of variable leader data, esp. attitude
+#----------------------------------------------------------------------
+
+sub writeData(@)
+{
+	my($fn,$dta) = @_;
+
+	die("writeData() needs \$WBRcfn from previous readData()")
+		unless (-r $WBRcfn);
+	$WBPcfn = $fn;
+	system("cp $WBRcfn $WBPcfn");
+
+	open(WBPF,"+<$WBPcfn") || die("$WBPcfn: $!");
+    WBPens($dta->{N_BINS},$dta->{FIXED_LEADER_BYTES},
+	                   \@{$dta->{ENSEMBLE}});
+}
+
+sub WBPens($$$)
+{
+	my($nbins,$fixed_leader_bytes,$E) = @_;
+	my($start_ens,$B1,$B2,$B3,$B4,$I,$id,$bin,$beam,$buf,$dummy,@dta,$i,$cs,@WBPofs);
+	my($ens,$ensNo,$dayStart,$ens_length,$BT_present,$hid,$did,$ndt);
+
+	for ($ens=$start_ens=0; 1; $ens++,$start_ens+=$ens_length+2) {
+
+		#----------------------------------------
+		# Get ensemble length and # of data types 
+		#----------------------------------------
+
+		sysseek(WBPF,$start_ens,0) || die("$WBPcfn: $!");
+		sysread(WBPF,$buf,6) == 6 || last;
+		($hid,$did,$ens_length,$dummy,$ndt) = unpack('CCvCC',$buf);
+		$hid == 0x7f || die(sprintf($FmtErr,$WBPcfn,"Header",$hid,0));
+		$did == 0x7f || die(sprintf($FmtErr,$WBPcfn,"Data Source",$did,0));
+		printf(STDERR "\n$WBPcfn: WARNING: unexpected number of data types (%d, ens=$ens)\n",$ndt),last
+				unless ($ndt == 6 || $ndt == 7);
+		$BT_present = ($ndt == 7);
+		sysread(WBPF,$buf,2*$ndt) == 2*$ndt || die("$WBPcfn: $!");
+		@WBPofs = unpack("v$ndt",$buf);
+		$fixed_leader_bytes = $WBPofs[1] - $WBPofs[0];
+	
+		#------------------------------
+		# Variable Leader
+		#------------------------------
+	
+		sysseek(WBPF,$start_ens+$WBPofs[1]+12,0) || die("$WBPcfn: $!");
+		
+		${$E}[$ens]->{XDUCER_DEPTH} *= 10;
+		${$E}[$ens]->{HEADING} *= 100;
+		
+		${$E}[$ens]->{PITCH} = unpack('S',pack('s',${$E}[$ens]->{PITCH}*100));
+		${$E}[$ens]->{ROLL}  = unpack('S',pack('s',${$E}[$ens]->{ROLL} *100));
+		${$E}[$ens]->{TEMPERATURE} =
+			unpack('S',pack('s',${$E}[$ens]->{TEMPERATURE}*100));
+
+		sysseek(WBPF,2,1);			# skip built-in test which reads as 0 but is usually undef		
+									# this was found not to matter, but there is no reason to edit
+#		my($b1);					# this field
+#		sysread(WBPF,$b1,14);
+#		sysseek(WBPF,-14,1);
+#		my($sos,$xd,$hdg,$pit,$rol,$sal,$tem) = unpack('vvvvvvv',$b1);
+
+		$buf = pack('vvvvvvv',
+			 ${$E}[$ens]->{SPEED_OF_SOUND},
+			 ${$E}[$ens]->{XDUCER_DEPTH},${$E}[$ens]->{HEADING},
+			 ${$E}[$ens]->{PITCH},${$E}[$ens]->{ROLL},
+			 ${$E}[$ens]->{SALINITY},${$E}[$ens]->{TEMPERATURE});
+
+#		unless ($b1 eq $buf) {
+#			printf(STDERR "ens = $ens\n");
+#			printf(STDERR "hdg: $hdg, ${$E}[$ens]->{HEADING}\n");
+#			printf(STDERR "xd: $xd, ${$E}[$ens]->{XDUCER_DEPTH}\n");
+#			printf(STDERR "pit: $pit, ${$E}[$ens]->{PITCH}\n");
+#			printf(STDERR "rol: $rol, ${$E}[$ens]->{ROLL}\n");
+#			printf(STDERR "sal: $sal, ${$E}[$ens]->{SALINITY}\n");
+#			printf(STDERR "tem: $tem, ${$E}[$ens]->{TEMPERATURE}\n");
+#
+#			printf(STDERR "read: %04X %04X %04X %04X %04X %04X %04X written: %04X %04X %04X %04X %04X %04X %04X\n",unpack('v7',$b1),unpack('v7',$buf));
+#
+#			die;
+#		}
+
+		my($nw) = syswrite(WBPF,$buf,14);
+		$nw == 14 || die("$WBPcfn: $nw bytes written ($!)");
+
+		#----------------
+		# Update Checksum
+		#----------------
+
+		sysseek(WBPF,$start_ens,0) || die("$WBPcfn: $!");
+		sysread(WBPF,$buf,$ens_length) == $ens_length || die("$WBPcfn: $!");
+		$cs = unpack('%16C*',$buf);
+		$buf = pack('v',$cs);
+		$nw = syswrite(WBPF,$buf,2);
+		$nw == 2 || die("$WBPcfn: $nw bytes written, ens=$ens ($!)");
+
+	} # ens loop
+}
+
+1;      # return true for all the world to see