Setting and Maintaining Arecibo Observatory's
Timing Systems
Donna Kubik
08/06/99
"A man with a watch knows what time it is. A man with two watches is never sure."
-- Segal's Law
PLEASE...
Please, only authorized personnel is allowed to make any adjustment of the timing
system.
1
Contents
Introduction to the Timing Room 2
Frequency Standards
Hydrogen Maser Frequency Standard 4
Rubidium Vapor Frequency Standard 14
Time Code Generators
TRAK Synchronized Time Code Generator 38
EECO Time Code Generator 58
TrueTime Time Code Generator 77
Transfer Standards
GPS Time Transfer Systems 109
Appendix 115
How to set up the HP5334A Universal Counter 116
Starting the Clock Comparator System 120
Starting the Ten-Tec PC Radio 126
2
Introduction to the Timing Room
There are three types of systems in the Timing Room: frequency standards, time
code generators, and transfer standards. In addition, an HP counter monitors time
differences between various 1PPS ticks under control of the Clock Computer System
(CCS).
Devices that produce a known frequency are called frequency standards. These
devices must be calibrated so that they remain within the tolerance required by the user's
application. Arecibo Observatory's application is the derivation of timing signals in
addition to provision of stable reference frequencies. Time code generators use the
output from the frequency standard to generate these timing signals.
The frequency standards must be calibrated by comparing them to a reference.
Since the oscillators in the frequency standards are sensitive to changing environmental
conditions and to being turned on and off, it is desirable to perform the calibration on site.
To do this, transfer standards are used to deliver a frequency reference from the national
standard at NIST to the observatory. Transfer standards are devices that receive and
process radio signals that provide traceablility to NIST. The radio signal is a link back to
the national standard. The observatory uses GPS as a transfer standard.
Since timing is an indispensable function at the observatory, redundancy has been
built into the system as shown in TABLE 1. Two identical Rubidium Vapor Frequency
Standards serve as backups to the Hydrogen Maser. The EECO Time Code Generator
can be used to generate the time codes if the TRAC Synchronized Time Code Generator
fails. Soon the TrueTime time code generator will also be available to serve as a backup.
It requires 50 ohm drivers to be installed, for the outputs are currently only TTL.
The two time transfer systems, the NBS/GPS Time Transfer System and the
TAC/GPS Time Transfer System, provide redundancy and also serve to cross check the
accuracy of the frequency standard.
System Device in service Backup
Frequency standard Hydrogen Maser Rubidium Vapor Frequency
Standard (2)
Time Code Generator TRAK Synchronized Time EECO Time Code
Code Generator Generator
Transfer standard NBS/GPS and TAC/GPS NBS/GPS and TAC/GPS
Time Transfer Systems Time Transfer Systems
(used simultaneously to (either could work alone
provide redundancy) should one fail)
TABLE 1 Timing room systems
3
The location of the frequency standards, time code generators, transfer standards,
HP counter, the PC-based shortwave radio, and the PC used to run the radio and CCS are
shown in FIG. 1.
TenTec
PC Radio
EECO Timecode
Generator
TrueTime Timecode
Generator
TRAK Timecode
Generator
HP5334A Universal
Counter
1 PPS MUX
5 MHz 10 MHz 20
MHz Buffers
Time Tick Buffers
NR Hydrogen
Maser IRIG Buffers
Time and
Frequency 100 MHz Buffers
Standard
NR-16 NBS/GPS Time
Transfer
Microprocessor/
Counter
NBS/GPS Time
TAC Transfer Receiver
PC PC
(used for TAC Rubidium Standard
CCS and PC #1
Radio) TAC/GPS Time
Transfer System Rubidium Standard
#2
UPS
FIG. 1 Timing room equipment
4
Hydrogen Maser Frequency Standard
Overview
This Overview is an outline of what needs to be done to restore operation of the
Hydrogen Maser Frequency Standard (HM) in selected failure modes. Step-by-step
instructions are presented in the next section, Procedure.
Some of the main components of a hydrogen maser are the hydrogen gas supply,
a controllable "leak" for the gas into the high vacuum system, a gas discharge to produce
atomic hydrogen, and a state selector which rejects atoms in the lower energy states and
focuses the higher states into the storage bulb.
A small storage bottle supplies molecular hydrogen to the gas discharge bulb. In
the discharge bulb, molecules of hydrogen are dissociated into atomic hydrogen. They
then pass through a source collimator and a magnetic state selector that filters atoms at
the desired atomic state and passes them to the resonance cavity.
The storage bulb is a quartz bulb that is coated inside with Teflon to control the
recombination rate of atoms into molecules. The quartz bulb is located in a precisely
machined pure copper cylinder which acts as a microwave resonant cavity for the 1420
MHz frequency of the 21 cm hydrogen line. Once the atoms enter the resonance cavity,
they find other atoms radiating and they fall in step. They "start to talk to each other" and
echo what they hear. This produces a highly coherent oscillation. This is the signal to
which the crystal oscillator is phase-locked. All of that is packaged in cabinets with
power supplies, temperature control, and magnetic shielding.
Great care is required to keep environmental disturbances small so that the full
performance potential of the HM clock can be realized. Since the operation of the HM is
complicated, only minor problems that can be corrected by a non-expert in a short
amount of time are addressed in the procedures that follow.
5
Procedure A: Frozen microprocessor display
If the HM microprocessor display (FIG. 1) is frozen (i.e., the time display is not
updating once per second), the following steps should restart the display.
WARNING!!!
These steps should be taken only if absolutely necessary and with great care, for
inadvertently entering the wrong data via the keypad can actually change physical
parameters of the maser. Hydrogen masers are very sensitive to such changes and could
render the maser incapable of generating useful output. Since the HM is the frequency
standard for the observatory, this would cause many problems! Please inform the
person(s) responsible for maintenance of the HM that the display was reset.
Microprocessor
Display
FIG. 1 Hydrogen Maser
6
Step 1 Before changing anything, record all the data currently displayed on all
five rows of the HM display (FIG. 2) in the Hydrogen Maser Logbook. Note especially
the value displayed on the right hand side of the third row. This is the Autotuner Register
and will be needed in a later step.
5 rows
of display
data
FIG. 2 Location of 5 rows of display data
7
Step 2 Open the display door by loosening the two screws on the right hand side
as shown in FIG. 3.
Screws on
right-hand side
of display door
FIG. 3 Location of display door screws
8
Step 3 Press the reset button located above the red LED bar graph display
RESET
button
FIG. 4 Location of HM display reset button
9
Step 4 Use the keypad to set the UTC display (FIG. 5) as follows:
To set Year: On keypad press 1* yy D
To set Day: On keypad press 2* dd D
To set Hour: On keypad press 3* hh D
To set Min: On keypad press 4* mm D
To set Sec: Set minutes high by one, and press D
Wait until zero seconds and release D
Seconds can be advanced or retarded by pressing 30* D or 31*D, respectively.
Keypad
UTC
display
FIG. 5 Location of HM UTC display and keypad
10
Step 5 Set the Autotuner Register to the value recorded before the RESET. The
Autotuner Register is the number on the right-hand side of the third row of the
Microprocessor Display (FIG. 6).
Use the keypad to set the Autotuner Register display (FIG. 6) as follows:
To set Autotuner Register: On keypad press 8* value D
Keypad
Autotuner
Display
FIG. 6 Location of Autotuner display and keypad
11
Procedure B: Checking nominal operating conditions
Agreement with nominal values for the HM operating parameters, such as
voltages, currents, pressures, etc., can be checked by comparing the present reading with
the nominal values marked on each gauge as shown in FIG. 7
Operating
parameter
gauges
FIG. 7 Gauges marked with nominal values
12
Procedure C: AC power
The presence of AC power is indicated by the green light on the front panel as
shown in FIG. 8.
AC power
indicator
FIG. 8 Location of AC power indicator
13
Procedure D: Heater
Check that the pink light is ON (FIG. 9), which indicates that the heater is
working.
Heater
indicator
light
FIG. 9 Location of heater indicator light
14
Rubidium Vapor Frequency Standard
Overview
This Overview is an outline of what needs to be done to restore operation of either
of the two 5065A Rubidium Vapor Frequency Standards (RUB 1 and RUB 2) in selected
failure modes. Step-by-step instructions are presented in the next section, Procedure.
The examples refer to RUB 1, but the same procedures apply to the other rubidium
standard, RUB 2.
Two failure modes are covered: an AC power failure is indicated by a flashing
BATTERY lamp (FIG. 1) and circuit malfunction is indicated when the green
CONTINUOUS OPERATION lamp is not lit (FIG. 1).
CONTINUOUS
OPERATION BATTERY
lamp lamp
FIG. 1 Location of BATTERY lamp and CONTINUOUS OPERATION lamp
If there is a power dip, the RUB battery lamp circuits may need to be reset. Step-
by-step instructions are presented in the next section, Procedure A: AC power failure.
If there is indication of circuit malfunction, the RUB will need to be reset and
resynced to the 1PPS output of the hydrogen maser (HM). Step-by-step instructions are
presented in section, Procedure B: Circuit malfunction.
15
Procedure A: AC Power Failure
Step 1 Flashing of the BATTERY lamp (FIG. 2) indicates that there was an
interruption in AC power.
BATTERY
lamp
FIG. 2 Location of BATTERY lamp
16
Step 2 To reset the battery lamp circuits after ac line failure, first open the door
on the front panel, as shown in FIG. 3.
Front panel
door
FIG. 3 Location of front panel door
17
Step 3 Switch the 3-position BATTERY switch (FIG. 4) to RESET position.
3-position
BATTERY
switch
FIG. 4 Location of 3-position BATTERY switch
18
Step 4 Return 3-position BATTERY switch (FIG. 5) to FAST CHARGE
position.
3-position
BATTERY
switch
FIG. 5 Location of 3-position BATTERY switch
19
Procedure B: Circuit malfunction
Step 1 Circuit malfunction is indicated when the green CONTINUOUS
OPERATION lamp is not lit (FIG. 6).
CONTINUOUS
OPERATION
lamp
FIG. 6 Location of CONTINUOUS OPERATION lamp
20
Step 2 Since you will need to use the 1PPS Multiplexer to send the 1PPS clock
signals from the HM to the RUB, you must first stop the Clock Computer System (CCS)
program that is automatically controlling which clock signals are sent via the 1PPS
Multiplexer to the A and B inputs of the counter.
The title bar of the CCS program indicates whether the program is running or
stopped. When running, the title bar will say CCS2 Windows Application – Clock
Comparator System – Running, as shown in FIG. 7. The timestamp under COUNTER
DATA will be updating every 2 seconds.
FIG. 7 View of CCS2 window when the CCS program is running.
21
Step 3 Stop the CCS program by clicking on the stop button (the square in the
upper left-hand corner underneath File shown in FIG. 8).
STOP
BUTTON
FIG. 8 Location of the Stop button used to halt automatic cycling of multiplexer outputs
by the CCS program.
22
Step 4 To verify that the program has stopped, check that the title bar now reads
CCS2 Windows Application - Clock Comparator System - Stopped, as shown in
FIG. 9. The timestamp under COUNTER DATA will no longer be updating.
FIG. 9 View of the CCS2 window when the program is stopped.
23
Step 5 Open the dialog box that allows you to manually select the outputs of the
multiplexer by clicking on the sideways E in the upper left-hand corner beneath Help,
shown in FIG. 10.
Sideways E
(for Manual Selection
dialog box)
FIG. 10 Location of interrupt to open the dialog box that allows you to manually
select multiplexer outputs.
24
A window like the one shown in FIG. 11 should appear. The current A-Input
Mux and B-Input Mux selections indicate which multiplexer outputs had been previously
selected.
FIG. 11 Dialog box used to manually choose multiplexer outputs
25
Step 6 Choose "MASER" as the input for both the A-Input Mux and the B-Input
Mux as shown in FIG. 12 by clicking on the two top-most buttons. Note: You will only
need to use one maser output, but setting both inputs to the maser eliminates any error
when cabling the multiplexer to the RUB in a later step.
FIG. 12 Dialog box with "MASER" selected for both A-Input Mux and for B-Input
Mux.
26
Step 7 Click on OK (FIG. 13), which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 13 Click on OK to activate choices in the dialog box, closing the window.
27
Step 8 Temporarily disconnect the Channel A or Channel B hydrogen maser
(HM) output, which comes from the front panel of the multiplexer (FIG. 14), from the HP
counter and connect it to the SYNC INPUT BNC connector on the rear panel of the RUB
(FIG. 15).
To SYNC
INPUT
on rear
panel of
RUB
HM output
from mux
FIG. 14 The hydrogen maser (HM) output from the multiplexer which goes to the SYNC
INPUT connector on rear panel of RUB
28
SYNC
INPUT
FIG. 15 Location of SYNC INPUT on rear panel of RUB
29
Step 9 Momentarily press the START-AUTO/START (FIG. 16) to START, then
release.
START-
AUTO/START
switch
FIG. 16 Location of the START-AUTO/START switch.
30
Step 10 Push the LOGIC RESET switch (FIG. 17).
LOGIC
RESET
switch
FIG. 17 Location of LOGIC RESET switch
31
Step 11 To resync, pull the rubidium clock forward out of the rack. Open the top
cover of the RUB and push the SYNC button (FIG. 18) which can be reached with a
toothpick
SYNC
button
FIG. 18 Location of the SYNC button
32
Step 12 After you have resynced the RUB, you need to verify that the RUB is
within 200ns of the HM using the HP5344A Universal Counter.
When the counter is properly set up, it displays the difference between Input A
and Input B.
Note: If there has been an interruption in power, the HP5334A Universal Counter
may not be set up correctly, because the power-up default settings are not the desired
settings. To set up the counter, see the section How to set up the HP5334A Universal
Counter.
Reconnect the cable from the multiplexer output to the counter. One output from
the multiplexer should be connected to Input A of the counter and the other multiplexer
output should be connected to Input B as shown in FIG. 19.
Counter
inputs
Multiplexer
outputs
FIG. 19 The outputs from the multiplexer connected to the A Input and the
B Input of the HP5344A Universal Counter
33
Step 13 In the dialog box used to manually choose multiplexer outputs, select
MASER as the A-Input Mux and choose RUB1 for the B-Input Mux as shown in
FIG. 20.
FIG. 20 Dialog box with "MASER" selected for A-Input Mux and "RUB1" selected for
B-Input Mux
34
Step 14 Click on OK (FIG. 21), which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 21 Click on OK to activate choices in the dialog box, closing the window.
35
Step 15 Check that the difference between the 1PPS from the HM and the 1PPS
from the RUB shown in the numeric display on the front panel of the counter is less than
200ns (FIG. 22). Important note: If the rubidium 1PPS tick comes first, the display will
fill with 999.999..... If so, reverse the cables to read the difference accurately, then put
them back to normal.
Numeric
display
FIG. 22 The difference between Input A and Input B of the counter shown in the
numeric display of the HP5334A Universal Counter.
The value shown is 16.309 microseconds.
36
Step 16 Put the CCS program back in automatic by clicking on the triangle
beneath File (FIG. 18).
START
BUTTON
FIG 23. Location of the Start button used to start automatic cycling of multiplexer
outputs by the CCS program
37
Step 17 Verify that the CCS program is now running by checking that the title bar
now reads CCS2 Windows Application - Clock Comparator System - Running, as
shown in FIG. 24. The timestamp under COUNTER DATA should be updating every 2
seconds.
FIG. 24 View of CCS2 window when the CCS program is running
38
TRAK Synchronized Time Code Generator
Overview
This Overview is an outline of what needs to be done to set up the TRAK
Synchronized Time Code Generator (TRAK). Step by step instructions are presented in
the next section, Procedure. The TRAK generates time codes for all observatory
operations. In particular, if it is set wrong the telescope will point in the wrong direction.
The goal is to first get the TRAK set to the correct time (day, hour, minute,
second) and then ensure that it is synchronized to within 200ns of the 1PPS output of the
hydrogen maser (HM).
Since you will need to use the 1PPS Multiplexer to send the desired 1PPS signals
to the TRAK for syncing and later to send the 1PPS clock signals from the HM and
TRAK to the HP5334A Universal Counter for comparison, you must first stop the Clock
Computer System (CCS) program that is automatically controlling which clock signals
are sent via the 1PPS Multiplexer to the A and B inputs of the counter.
The TRAK clock is first set up by giving it a sync pulse from the HM at the time
you set with one-second resolution on a thumbwheel switch on the front panel of the
TRAK. The correct time is verified by comparing the time displayed on the front panel
of the TRAK clock with WWV time announcements.
The counter is then used to check that the TRAK is synchronized to within 200ns
of the HM.
IMPORTANT: WWV and the HM report Coordinated Universal Time (UTC)
time while the TRAK and EECO clock display Atlantic Standard Time (AST). The
result of this is that the number of hours displayed on the HM will be 4 hours greater than
the number of hours displayed on the TRAC or EECO clock.
39
Procedure
Step 1 The title bar of the CCS program indicates whether the program is running
or stopped. When running, the title bar will say CCS2 Windows Application – Clock
Comparator System – Running, as shown in FIG. 1. The timestamp under COUNTER
DATA will be updating every 2 seconds.
FIG. 1 View of CCS2 window when the CCS program is running.
40
Step 2 Stop the CCS program by clicking on the stop button (the square in the
upper lefthand corner underneath File shown in FIG. 2).
STOP
BUTTON
FIG. 2 Location of the Stop button used to halt automatic cycling of multiplexer outputs
by the CCS program.
41
Step 3 To verify that the program has stopped, check that the title bar now reads
CCS2 Windows Application - Clock Comparator System - Stopped, as shown in FIG.
3. The timestamp under COUNTER DATA will no longer be updating.
FIG. 3 View of the CCS2 window when the program is stopped.
42
Step 4 Open the dialog box that allows you to manually select the outputs of the
multiplexer by clicking on the sideways E in the upper lefthand corner beneath Help,
shown in FIG. 4.
Sideways E
(for Manual Selection
dialog box)
FIG. 4 Location of interrupt to open the dialog box that allows you to manually select
multiplexer outputs.
43
A window like the one shown in FIG. 5 should appear. The current A-Input Mux
and B-Input Mux selections indicate which multiplexer outputs had been previously
selected.
FIG. 5 Dialog box used to manually choose multiplexer outputs
44
Step 5 Choose "MASER" as the input for both the A-Input Mux and the B-Input
Mux as shown in FIG. 6 by clicking on the two top-most buttons. Note: You will only
need to use one maser output, but setting both inputs to the maser eliminates any error
when cabling the multiplexer to the TRAK in the next step.
FIG. 6 Dialog box with "MASER" selected for both A-Input Mux and for B-Input Mux.
45
Step 6 Click on OK (FIG. 7), which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 7 Click on OK to activate choices in the dialog box, closing the window.
46
Step 7 Temporarily disconnect the hydrogen maser (HM) output, which comes
from the front panel of the multiplexer (Channel A or Channel B), from the HP counter,
and connect it to EXT START on the front panel of the TRAK as shown in FIG. 8.
EXT
START
HM output
from mux
FIG. 8 The hydrogen maser (HM) output from the mux connected to the EXT START
input on the TRAK.
47
Step 8 Put the GEN/SU/SYNC switch located on the front panel of the TRAK in
the SU (set up) position as shown in FIG. 9.
GEN/SU/SYNC
switch
FIG. 9 The GEN/SU/SYNC switch in the SU (set up) position.
48
Step 9 To start the PC radio program to tune in WWV, see Starting the Ten-Tec
PC Radio Program (Appendix C).
To determine the current time, listen for the WWV tone that marks the announced
time every minute.
Via the thumbwheel switches on the front panel of the TRAK (FIG. 10), dial in
the day, hour, minute, and second you want to start the TRAK at. Since you will be using
WWV minute time tick to start the clock, the number of seconds should be "00".
Thumbwheel
switches
FIG. 10 Select time to start the TRAK with thumbwheel switches
49
Step 10 Listen for the WWV tone that marks the beginning of each minute. When
the tone sounds, push the ENTER button on the TRAK, as shown in FIG. 11. This
should start the TRAK at the start of the minute. Hitting the ENTER button at exactly the
correct time may take some practice. If the next step (Step 11) indicates that the TRAK
started on the wrong pulse, just try again.
Enter
button
FIG. 11 Hitting the ENTER button manually enters the preset time on the
thumbwheel switch
50
Step 11 To check that the TRAK started on the desired second, listen for the
WWV tone that marks the beginning of the next minute. There should be "00" seconds
displayed on the LED readout on the TRAK (FIG. 12) when the time is announced on
WWV because WWV announces the time for each integer number of minutes. If the
seconds displayed on the TRAK agrees with time reported by WWV, proceed to the next
step. If the number of seconds does not agree with WWV, try Step 9 and Step 10 again.
Seconds
display
FIG. 12 TRAK clock (AST) time display
51
Step 12 After you have verified that the TRAK is on the correct second, you need
to verify that the TRAK is within 200ns of the HM using the HP5344A Universal
Counter.
When the counter is properly set up, it displays the difference between Input A
and Input B.
Note: If there has been an interruption in power, the HP5334A Universal Counter
may not be set up correctly, because the power-up default settings are not the desired
settings. To set up the counter, see the section How to set up the HP5334A Universal
Counter (Appendix A).
Reconnect the cable from the multiplexer output to the counter. One output from
the multiplexer should be connected to Input A of the counter and the other multiplexer
output should be connected to Input B as shown in FIG. 13.
Counter
inputs
Multiplexer
outputs
FIG. 13 The outputs from the multiplexer connected to the A Input and the
B Input of the HP5344A Universal Counter
52
Step 13 In the dialog box used to manually choose multiplexer outputs, select
MASER as the A-Input Mux and choose TRAK for the B-Input Mux as shown in FIG.
14.
FIG. 14 Dialog box with "MASER" selected for A-Input Mux and "TRAK" selected for
B-Input Mux
53
Step 14 Click on OK (FIG. 15), which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 15 Click on OK to activate choices in the dialog box, closing the window.
54
Step 15 Check that the difference between the 1PPS from the HM and the 1PPS
from the TRAK shown in the numeric display on the front panel of the counter is less
than 200ns (FIG. 16). Important note: If the TRAK 1PPS tick comes first, the display
will fill with 999.999..... If so, reverse the cables to read the difference accurately, then
put them back to normal.
Numeric
display
FIG. 16 The difference between Input A and Input B of the counter shown in the
numeric display of the HP5334A Universal Counter
55
Step 16 Put the GEN/SU/SYNC switch on the TRAK back in GEN (generate)
mode (FIG. 17).
GEN/SU/SYNC
switch
56
Step 17 Put the CCS program back in automatic by clicking on the triangle
beneath File (FIG. 18).
START
BUTTON
FIG 18. Location of the Start button used to start automatic cycling of multiplexer
outputs by the CCS program
57
Step 18 Verify that the CCS program is now running by checking that the title bar
now reads CCS2 Windows Application - Clock Comparator System - Running, as
shown in FIG. 19. The timestamp under COUNTER DATA should be updating every 2
seconds.
FIG. 19 View of CCS2 window when the CCS program is running
58
EECO Time Code Generator
Overview
This Overview is an outline of what needs to be done to set up the EECO Time
Code Generator (EECO). Step by step instructions are presented in the next section,
Procedure.
The goal is to first get the EECO Time Code Generator (EECO) set to the correct
time (day, hour, minute, second) and then ensure that it is synchronized to within 1us of
the 1PPS output of the hydrogen maser (HM).
The EECO clock is set up by first setting its accumulators to the time you indicate
with one-minute resolution on the thumbwheel switch. The correct time is verified by
comparing the time displayed on the front panel of the EECO clock with WWV time
announcements.
Next you will need to use the 1PPS Multiplexer to send the 1PPS clock signals
from the HM and EECO to the HP5334A Universal Counter for comparison. You must
first stop the Clock Computer System (CCS) program that is automatically controlling
which clock signals are sent via the 1PPS Multiplexer to the A and B inputs of the
counter. The CCS program will be used to control the inputs to the counter. The counter
can then be used to check, and if necessary, aid in readjusting synchronization to the HM.
IMPORTANT: WWV and the HM report Coordinated Universal Time (UTC)
time while the TRAK and EECO clock display Atlantic Standard Time (AST). The
result of this is that the number of hours displayed on the HM will be 4 hours greater than
the number of hours displayed on the TRAC or EECO clock.
59
Procedure
Step 1 To access the controls for the ECCO clock, open the long, horizontal
hinged door on the front panel (FIGS. 1 & 2).
Long, horizontal,
hinged door
FIG. 1 Location of hinged door used to guard controls to prevent accidental time change
or desynchronization of EECO Time Code Generator
Front panel
controls
FIG. 2 EECO front panel controls behind door
60
Step 2 To start the WWV program, see Starting the Ten-Tec PC Radio
Program (Appendix C).
To determine the current time, listen for the WWV tone that marks the announced
time every minute.
Dial in the day, hour, and minute you want to reset the EECO accumulators to via
the TIME PRESET thumbwheel switches as shown in FIG. 3.
Thumbwheel
switches
FIG. 3 Select time to start EECO with the TIME PRESET thumbwheel switches
61
Step 3 To reset the accumulators on the EECO, first switch the RUN/PRESET
switch to the PRESET postion (FIG. 4).
RUN/PRESET
switch
FIG. 4 RUN/PRESET switch in PRESET position
62
Step 4 Listen for the WWV time. (To start the WWV program, see Starting the
Ten-Tec PC Radio Program - Appendix C) . Set the thumbwheel registers to the next
full minute. Press the SET button (at any time) to transfer the thumbwheel contents to
the display.
SET
button
FIG. 5 Push SET on the EECO to set the accumulators to the time on the thumbwheel
switches.
63
Step 5 Within one second after the preset time occurs, set the RUN/PRESET
switch to the RUN position (FIG. 6).
RUN/PRESET
switch
FIG. 6 RUN/PRESET switch in RUN position
64
Step 6 To check that the EECO started on the desired second, listen for the WWV
tone that marks the beginning of the next new minute. There should be "00" seconds
displayed on the Nixie tube readout on the EECO (FIG. 7). WWV announces the time
for each integer number of minutes. If the seconds displayed on the EECO agrees with
time reported by WWV, proceed to the next step. If the number of seconds does not
agree with WWV, try Steps 2, 3, 4,and 5 again.
Seconds
display
FIG. 7 EECO Nixie tube (AST) time display
65
Step 7 After you have verified that the EECO is on the correct second, you need
to verify that the TRAK is within 1us (the highest resolution available on the ADV-RET
RATE rotary switch) of the HM by using the HP5334A Universal Counter.
When the counter is properly set up, it displays the difference between Input A
and Input B.
Note: If there has been an interruption in power, the HP5334A Universal Counter
may not be set up correctly, because the power-up default settings are not the desired
settings. To set up the counter, see the section How to set up the HP5334A Universal
Counter (Appendix A).
Check that the multiplexer outputs are connected to the inputs to the counter. One
output from the multiplexer should be connected to Input A of the counter and the other
multiplexer output should be connected to Input B as shown in FIG. 8.
Counter
inputs
Multiplexer
outputs
FIG. 8 The outputs from the multiplexer connected to the A Input and the
B Input of the HP5344A Universal Counter
66
Step 8 Since you will need to use the 1PPS Multiplexer to send the 1PPS clock
signals from the HM and EECO clock to the HP5334A Universal Counter for
comparison, you must first stop the Clock Computer System (CCS) program that is
automatically controlling which clock signals are sent via the 1PPS multiplexer to the A
and B inputs of the counter.
The title bar of the CCS program indicates whether the program is running or
stopped. When running, the title bar will say CCS2 Windows Application – Clock
Comparator System – Running, as shown in FIG. 9. The timestamp under COUNTER
DATA will be updating every 2 seconds.
FIG. 9 View of CCS2 window when the CCS program is running.
67
Step 9 Stop the CCS program by clicking on the stop button (the square in the
upper left-hand corner underneath File shown in FIG. 10).
STOP
BUTTON
FIG. 10 Location of the Stop button used to halt automatic cycling of multiplexer outputs
by the CCS program.
68
Step 10 To verify that the program has stopped, check that the title bar now
reads CCS2 Windows Application - Clock Comparator System - Stopped, as shown
in FIG. 11. The timestamp under COUNTER DATA will no longer be updating.
FIG. 11 View of the CCS2 window when the program is stopped.
69
Step 11 Open the dialog box that allows you to manually select the outputs of the
multiplexer by clicking on the sideways E in the upper left-hand corner beneath Help,
shown in FIG. 12.
Sideways E
(for Manual Selection
dialog box)
FIG. 12 Location of interrupt to open the dialog box that allows you to manually select
multiplexer outputs.
70
A window like the one shown in FIG. 13 should appear. The current A-Input
Mux and B-Input Mux selections indicate which multiplexer outputs had been previously
selected.
FIG. 13 Dialog box used to manually chose multiplexer outputs
71
Step 12 Choose "MASER" as the input for the A-Input Mux and chose "EECO"
for the B-Input Mux as shown in FIG. 14, by clicking on the respective buttons.
FIG. 14 Dialog box with "MASER" selected for both A-Input Mux and with "EECO"
selected for B-Input Mux.
72
Step 13 Click on OK (FIG. 15) which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 15 Click on OK to activate choices in the dialog box, closing the window.
73
Step 14 Check that the difference between the 1PPS from the HM and the 1PPS
from the EECO shown in the numeric display on the front panel of the counter is less
than 1us (FIG. 16). Important note: If the EECO 1PPS tick comes first, the display will
fill with 999.999..... If so, reverse the cables to read the difference accurately, then put
them back to normal.
Numeric
display
FIG. 16 The difference between Input A and Input B of the counter shown in the
numeric display of the HP5334A Universal Counter. The value shown below is 16.309
microseconds.
74
Step 15 If the difference between the HM and EECO is not within 1us (as
indicated by numeric display on the counter), use the ADV-RET momentary switch (FIG.
17) to slew the time until the difference between the EECO and HM is less than 1us. The
switch will slew at the rate indicated on the ADV-RET RATES rotary switch (FIG. 17).
ADVANCE ADV RET
RETARD RATES
momentary rotary
switch switch
FIG. 17 Use the ADVANCE RETARD switch to adjust the EECO to be within 1us of
the HM
75
Step 16 Put the CCS program back in automatic by clicking on the triangle
beneath File (FIG. 18).
START
BUTTON
FIG 18. Location of the Start button used to start automatic cycling of multiplexer
outputs by the CCS program
76
Step 17 Verify that the program is now running by checking that the title bar now
reads CCS2 Windows Application - Clock Comparator System - Running, as shown
in FIG. 19. The timestamp under COUNTER DATA should be updating every 2
seconds.
FIG. 19 View of CCS2 window when the CCS program is running
77
TrueTime Time Code Generator
Overview
This Overview is an outline of what needs to be done to set up the TrueTime Time
Code Generator (TrueTime). Step by step instructions are presented in the next section,
Procedure.
The goal is to first get the TrueTime set to the correct time (day, hour, minute,
second) and then ensure that it is synchronized to within 200ns of the 1PPS output of the
hydrogen maser (HM).
Since you will need to use the 1PPS Multiplexer to send the desired 1PPS signals
to the TrueTime for syncing and later to send the 1PPS clock signals from the HM and
TrueTime to the HP5334A Universal Counter for comparison, you must first stop the
Clock Computer System (CCS) program that is automatically controlling which clock
signals are sent via the 1PPS Multiplexer to the A and B inputs of the counter.
The TrueTime clock is first set up by giving it a 1PPS sync pulse from the HM at
the start time you set on the front panel alphanumeric (A/N) display of the TrueTime.
The correct time is verified by comparing the time displayed on the front panel numeric
display of the TrueTime with WWV time announcements.
The counter is then used to check that the TrueTime is synchronized to within
200ns of the HM.
IMPORTANT: WWV and the HM report Coordinated Universal Time (UTC)
time while the TRAK, EECO, and TrueTime clocks display Atlantic Standard Time
(AST). The result of this is that the number of hours displayed on the HM will be 4
hours greater than the number of hours displayed on the Truetime or EECO clock.
78
Procedure
Step 1 The title bar of the CCS program indicates whether the program is running
or stopped. When running, the title bar will say CCS2 Windows Application – Clock
Comparator System – Running, as shown in FIG. 1. The timestamp under COUNTER
DATA will be updating every 2 seconds.
FIG. 1 View of CCS2 window when the CCS program is running.
79
Step 2 Stop the CCS program by clicking on the stop button (the square in the
upper lefthand corner underneath File shown in FIG. 2).
STOP
BUTTON
FIG. 2 Location of the Stop button used to halt automatic cycling of multiplexer outputs
by the CCS program.
80
Step 3 To verify that the program has stopped, check that the title bar now reads
CCS2 Windows Application - Clock Comparator System - Stopped, as shown in FIG.
3. The timestamp under COUNTER DATA will no longer be updating.
FIG. 3 View of the CCS2 window when the program is stopped.
81
Step 4 Open the dialog box that allows you to manually select the outputs of the
multiplexer by clicking on the sideways E in the upper lefthand corner beneath Help,
shown in FIG. 4.
Sideways E
(for Manual Selection
dialog box)
FIG. 4 Location of interrupt to open the dialog box that allows you to manually select
multiplexer outputs.
82
A window like the one shown in FIG. 5 should appear. The current A-Input Mux
and B-Input Mux selections indicate which multiplexer outputs had been previously
selected.
FIG. 5 Dialog box used to manually choose multiplexer outputs
83
Step 5 Choose "MASER" as the input for both the A-Input Mux and the B-Input
Mux as shown in FIG. 6 by clicking on the top-most buttons. Note: You will only need
to use one maser output, but setting both inputs to the maser eliminates any error when
cabling the multiplexer to the TrueTime in the next step.
FIG. 6 Dialog box with "MASER" selected for both A-Input Mux and for B-Input Mux.
84
Step 6 Click on OK (FIG. 7), which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 7 Click on OK to activate choices in the dialog box, closing the window.
85
Step 7 Connect the 1PPS hydrogen maser (HM) output from the front panel of
the multiplexer (Channel A or Channel B) to EXT START on the rear panel of the
TrueTime as shown in FIG. 8.
EXT
START
1PPS HM
output
from MUX
FIG. 8 The hydrogen maser (HM) output from the mux connected to the EXT START
input on the rear panel of the TrueTime.
86
Step 8 Before syncing the TrueTime to the maser, the TrueTime must be stopped
and it must be in Generate mode. Step 8 describes how to stop the Truetime and Steps 9-
13 describe how to insure it is in Generate mode.
To stop the TrueTime, press the STOP key (FIG. 9). When stopped, the yellow
LED (FIG. 9) above the STOP key will be lit.
Yellow
LED stop
indicator
STOP key
FIG. 9 Location of the STOP key and its yellow LED indicator.
87
Step 9 To check that the TrueTime is in Generate mode, first push key #0. The
message: "OPERATIONAL MODE, Generator (or Sync Generator) " should appear in
the alphanumeric (A/N) display.
OPERATIONAL MODE
Generator (or Sync Generator)
Key #0
FIG. 10 Location of key #0 and expected message in A/N display
88
Step 10 To change modes, push the Setup key (FIG. 11). This should
result in the message: "CHANGE MODE, Generator (or Sync Generator), Push
ENTER to Load" in the A/N display (FIG. 11).
CHANGE MODE
Generator (or Sync Generator)
Push ENTER to Load
SETUP
key
FIG. 11 Location of the "SETUP" key and expected message in A/N display
89
Step 11 To toggle between the two available modes, Generator and Sync
Generator, push key #0 (FIG. 12).
Key #0
FIG. 12 Location of key #0 used to toggle between mode options
90
Step 12 To select Generator mode, push ENTER when Generator is shown
in the A/N display.
CHANGE MODE
Generator
Push ENTER to Load
ENTER
key
FIG. 13 Location of ENTER key
91
Step 13 After pushing ENTER, the A/N display should read: "OPERATIONAL
MODE, Generator".
OPERATIONAL MODE
Generator
FIG. 14 Check that mode choice is Generator
92
Step 14 Now that you have checked that the TrueTime is stopped and in Generator
mode, you are ready to set the time at which you plan to sync the TrueTime to the 1PPS
of the maser.
Push Key #1 (FIG. 15). The alphanumeric display should read: "GENERATOR
STATUS, 100:13:11:50 (or whatever the current time is), Gen Stopped".
GENERATOR STATUS
100:13:11:50 (or whatever the current time is)
Gen Stopped
Key #1
FIG. 15 Location of Key #1 for setting sync time and resultant message in A/N display.
93
Step 15 Pressing SETUP key (FIG. 16) will cause the curser to flash under the
time indicating that the time may be changed. The message in the A/N display will now
read "CHANGE GEN TIME, 100:13:11:50 (or whatever the current time is), Push
ENTER to load". Step 16 will describe how to choose the time.
CHANGE GEN TIME
100:13:11:50 (or whatever the current time is)
Push ENTER to load
Flashing
cursor
SETUP
key
FIG. 16 Location of SETUP key and curser indicating time to be changed.
94
Step 16 To decide on what time to set, start the PC radio program to tune in
WWV, see Starting the Ten-Tec PC Radio Program (Appendix C).
To determine the current time, listen for the WWV tone that marks the announced
time every minute.
Use the numeric keypad (FIG. 17) to enter the desired start time for syncing
theTruetime. Since you will be using WWV minute time tick to start the clock, the
number of seconds should be "00".
(Note: You will probably want to select a time that is about 5 minutes from the
present time in order to give yourself a few minutes to do the following steps of arming
the TrueTime for syncing)
Numeric
keypad
FIG. 17 Select time to start the Truetime with the numeric keypad
95
Step 17 Hit ENTER to load the starting time (FIG.18). The A/N display should
read: "GENERATOR STATUS, 100:13:20:00 (or whatever time you chose to start),
Gen Stopped" (FIG. 18).
GENERATOR STATUS
100:13:20:00 (or whatever time you chose to start)
Gen Stopped
ENTER
key
FIG. 18 Location of ENTER key and resultant message in A/N display
96
Step 18 To properly arm the TrueTime for synching, push Key #3 (FIG. 19).
Repeatedly pushing Key #3 will display several choices. Push Key #3 until the
alphanumeric display reads: "GEN EXTERNAL START, (on rising or falling edge),
Push ENTER to enable" (FIG. 19).
GEN EXTERNAL START
(on rising or falling edge)
Push ENTER to enable
Key #3
FIG. 19 Location of Key #3 and resultant message on A/N display
97
Step 19 Push SETUP to move the curser in the A/N display to the second line
(FIG. 20). The A/N display will read "CHANGE EDGE SELECT (rising or falling
edge), Push ENTER to load" (FIG. 20).
CHANGE EDGE SELECT
(rising or falling edge)
Push ENTER to load
SETUP
key
FIG. 20 Location of SETUP key and resultant message in A/N display
98
Step 20 Key #3 will toggle between the choices rising edge and falling edge.
CHANGE EDGE SELECT
(rising or falling edge)
Push ENTER to Load
Key #3
FIG. 21 Location of Key #3, which toggles between rising and falling
edge.
99
Step 21 When rising edge is displayed, hit ENTER (FIG 22). This will result in
the message: "GEN EXTERNAL START , (on rising edge), Push ENTER to enable", on
the A/N display (FIG. 22).
GEN EXTERNAL START
(on rising edge)
Push ENTER to enable
ENTER
key
FIG. 22 Location of ENTER key and resultant message in A/N display after chosing
rising edge
100
Step 22 Push ENTER key (FIG. 23) to enable syncing. This will enable the LED
above the START switch (FIG. 23) which will flash at the occurrance of each External
Start edge (each rising edge of the 1 PPS signal at the external input). Note: The STOP
LED will still be on while the START LED is flashing until you have actually synced the
TrueTime in the next step.
GEN EXTERNAL START Flashing
Push START to arm
yellow
Push STOP to abort LED
ENTER
key
FIG. 23 Location of ENTER key and flashing yellow LED indicator
101
Step 23 Listen for the WWV tone that marks the beginning of each minute. When
the tone sounds, push the START button on the TrueTime, as shown in FIG. 24. This
should start the TrueTime at the start of the minute. Hitting the START button at exactly
the correct time may take some practice. If the next step (Step 24) indicates that the
TrueTime started on the wrong 1PPS pulse, just try again, starting at Step 14.
START
button
FIG. 24 Hitting the START button manually enters the preset time set on
the alphanumeric display, thus syncing the TrueTime to the HM
102
Step 24 To check that the TrueTime started on the desired second, listen for the
WWV tone that marks the beginning of the next minute. There should be "00" seconds
displayed on the numeric readout on the TrueTime (FIG. 25). If the seconds displayed on
the TrueTime agrees with time reported by WWV, proceed to the next step. If the
number of seconds does not agree with WWV, try the procedure again, starting at Step
14.
Seconds
display
FIG. 25 TrueTime clock (AST) time display
103
Step 25 After you have verified that the TrueTime is on the correct second, you
need to verify that the TrueTime is within 200ns of the HM using the HP5344A
Universal Counter.
When the counter is properly set up, it displays the difference between Input A
and Input B.
Note: If there has been an interruption in power, the HP5334A Universal Counter
may not be set up correctly, because the power-up default settings are not the desired
settings. To set up the counter, see the section How to set up the HP5334A Universal
Counter.
Reconnect the cable from the multiplexer output to the counter. One output from
the multiplexer should be connected to Input A of the counter and the other multiplexer
output should be connected to Input B as shown in FIG. 26.
Counter
inputs
Multiplexer
outputs
FIG. 26 The outputs from the multiplexer connected to the A Input and the
B Input of the HP5344A Universal Counter
104
Step 26 In the dialog box used to manually chose multiplexer outputs, select
TTIME (for TrueTime) as the A-Input Mux and choose MASER for the B-Input Mux as
shown in FIG. 27.
FIG. 27 Dialog box with "TTIME" selected for A-Input Mux and "MASER" selected for
B-Input Mux
105
Step 27 Click on OK (FIG. 28), which will close the window and activate your
choice. Note: Any changes in the dialog box will not be activated until that window is
closed by clicking on OK.
Click on
OK
FIG. 28 Click on OK to activate choices in the dialog box, closing the window.
106
Step 28 Check that the difference between the 1PPS from the HM and the 1PPS
from the TrueTime shown in the numeric display on the front panel of the counter is less
than 200ns (FIG. 29). Important note: If the TrueTime 1PPS tick comes first, the
display will fill with 999.999..... If so, reverse the cables to read the difference
accurately, then put them back to normal.
Numeric
display
FIG. 29 The difference between Input A and Input B of the counter shown in the
numeric display of the HP5334A Universal Counter.
The value shown is 16.309 microseconds.
107
Step 29 Put the CCS program back in automatic by clicking on the triangle
beneath File (FIG. 30).
START
BUTTON
FIG. 30 Location of the Start button used to start automatic cycling of multiplexer
outputs by the CCS program
108
Step 30 Verify that the CCS program is now running by checking that the title bar
now reads CCS2 Windows Application - Clock Comparator System - Running, as
shown in FIG. 31. The timestamp under COUNTER DATA should be updating every 2
seconds.
FIG. 31 View of CCS2 window when the CCS program is running
109
GPS Time Transfer Systems
Both GPS-based time transfer systems, the NBS/GPS Time Transfer System, also
referred to as the NIST Time Transfer System and the TAC/GPS Time Transfer System,
also referred to as the Princeton Time Transfer System or Joe Taylor's Time Transfer
System, are designed to start up unassisted upon power restoration.
The NBS/GPS and the TAC/GPS Time Transfer Systems each has its own GPS
antenna and receiver, referred to as GPS1 and GPS2 respectively, which is used as a
transfer standard. Transfer standards are devices that receive and process radio signals
that provide frequency traceable to NIST. The purpose of each system is to monitor the
reliability of the frequency derived from the Hydrogen Maser (HM).
The NBS/GPS Time Transfer System generates a 1 PPS signal from GPS1 and
compares it to a 1 PPS output from the HM.
The TAC/GPS Time Transfer System compares a 1 PPS output from the TRAC,
which is generated from a 5 MHz output of the HM, to a 1 PPS signal that the TAC
(Totally Accurate Clock) generates from GPS2. Note: There is a second 1 PPS output
from the HM, but it is used for the Clock Comparator System. Lacking an unused direct
1 PPS output from the HM, the TAC-GPS Time Transfer System uses the 1 PPS signal
generated by the TRAK, which is directly related to the HM since it is generated from a
5 MHz HM output. This is the same 1PPS signal used by all other systems at the
Observatory except NBS/GPS.
Following is a brief description of each time transfer system and how to verify
that the system is functioning correctly.
110
NBS-GPS Time Transfer System
The NBS/GPS Time Transfer System is shown in FIG.1 and FIG. 2.
NBS/GPS TIME TRANSFER NBS/GPS TIME TRANSFER
RECEIVER MICROPROCESSOR/COUNTER
FIG. 1 NBS/GPS Time Transfer System
NBS/GPS TIME TRANSFER
1 PPS MICROPROCESSOR
from HM COUNTER
1 PPS 5 MHz
from receiver from receiver
NBS/GPS TIME TRANSFER 50 MHz LO
5 MHz ref RECEIVER to antenna
from HM
IF
from antenna
FIG. 2 Block diagram of NBS/GPS Time Transfer System
111
There are three kinds of data essential for the operation of the NBS/GPS Time
Transfer System: an almanac of GPS satellite coordinates, local coordinates of the
antenna, and UTC time. A "fail-safe" card is included in the microprocessor to store and
protect this essential data, along with programmed track times and the 19 most recent
data points. In case of power failure, battery backup will continue operation of the
"failsafe" card for at least two years. Normally if power is lost, after power is restored
this essential data will be reloaded and the system will resume normal operation.
Thus, the system should always have almanac data and UTC time. Local coordinates can
be determined upon initial startup using the navigation program contained in the system.
The top line of the CRT display on the NBS/GPS Time Transfer Microprocessor
Counter displays the UTC clock. Messages of error conditions appear in a large, reverse-
video rectangular box in the center of the CRT display. To check that the system is
running, turn on the CRT display and check that it is free of error messages and that UTC
is being updated (FIG. 3). Turn off the video display after use.
CRT CRT
display on/off
control
FIG. 3 Location of CRT display
112
The National Institute of Standards and Technology (NIST) monitors the same
satellites at the same times we do, several times a day. The measurememnts accumulated
at Arecibo Observatory are automatically downloaded via modem every night to NIST in
Boulder, Colorado. We receive a monthly report from NIST giving the time history of
the hydrogen maser.
113
TAC/GPS Time Transfer System
The TAC/GPS Time Transfer System is shown in FIG. 4 and FIG. 5.
CPU + (currently-used) Counter
1 PPS GPS antenna input
located behind the
to CCS and
(unused) Time Interval Counter
1 PPS output to counter
(TAC rear panel)
TAC
Time
Interval
Counter
(currently
not used)
FIG. 4 TAC/GPS Time Transfer System
GPS
Antenna
1575.42 MHz
GPS carrier
CPU 1 PPS from TAC TAC
Counter
1 PPS from TRAK
10 MHz from 10 MHz buffer
FIG. 5 Block diagram of TAC/GPS Time Transfer System
114
The computer and TAC run from their own uninterruptible power supply.
Therefore, they should keep running through most brief power glitches. After a hard
reboot the computer will come up automatically running a specified program script,
normally the one that controls the clock offset measurements.
If the system is running, the red LED below the 1 PPS output on the front panel
will be flashing and the computer monitor display will be updating (FIG. 6).
Monitor Flashing
display red LED
updating
FIG. 6 Location of indicators that TAC-GPS Time Transfer System is running
115
Appendix
116
How to set up the HP5334A Universal Counter
Procedure
If there has been an interruption in power, the HP5334A Universal Counter may
not be set up correctly, for the power-up default settings are not the desired settings.
When set up correctly, the front panel of the counter appears as in FIG. 1. The
REM, TLK, PRESET and S annunciator LEDs are on, and 50 Ω Z should be selected for
INPUT A and INPUT B. AUTO TRIG should NOT be selected.
TLK S 50Ω Z 50Ω Z
REM PRESET TI A → B
FIG. 1 HP5334A Universal Counter Settings
117
Every 2 seconds, the CCS program reads a data value from the counter.
The yellow trigger LEDs for INPUT A and INPUT B and the GATE annunciator will
light during each read cycle as shown in FIG. 2.
GATE INPUT A INPUT B
TRIGGER TRIGGER
FIG. 2 Indicators that should be observed to be ON during each read cycle
generated by the CCS program
If the above settings are not observed, the desired settings can be restored
via the following four steps.
1. Press the RESET/LOCAL key
2. Press RECALL
3. Press the numeric "5" key (also labelled TI A → B )
4. Make sure AUTO TRIG is OFF!
118
Step 1
Press
RESET/LOCAL
Step 2
Press
RECALL
119
Step 3
Press "5"
Step 4
Check that
AUTO TRIG is
OFF
120
Starting the Clock Comparator System
The Clock Comparator System (CCS) has two functions: to control which clock
signals are sent to the A and B inputs of the HP 5334A Universal Counter and to record
the comparison the counter makes of the two signals.
Step 1 Check to see if the CCS program is running on the PC in the timing room.
If the application is running, it may be open (FIG. 1), or it may be iconized (FIG. 2).
FIG. 1 View of the Clock Comparator System application
121
Clock
Comparator
System
icon
FIG. 2 View of Clock Comparator System icon
122
Step 2 If the CCS program is not running, it can be started via
Bigdisk (C:) → Ccs → Ccs2.exe
as shown in FIGS. 3, 4, and 5.
Open
Bigdisk (C:)
FIG. 3 View of Bigdisk (C:) icon
123
Open
Ccs folder
FIG. 4 Location of CCS folder
124
Start application
by clicking on
Ccs2.exe
FIG. 5 Location of Clock Comparator System application
125
Step 4 The title bar of the CCS program indicates whether the program is running
or stopped. When running, the title bar will say CCS2 Windows Application – Clock
Comparator System – Running, as shown in FIG. 6. The timestamp under COUNTER
DATA will be updating every 2 seconds.
FIG. 6 View of CCS2 window when the CCS program is running.
126
Starting the Ten-Tec PC Radio
Overview
This Overview is only an outline of what needs to be done to start up the Ten-Tec
PC Radio. Step-by-step instructions are presented in the following section, Procedure.
The Ten-Tec PC Radio is a PC-based shortwave radio wide coverage receiver
which covers full MF and HF range from 0.3-30 MHz, including WWV and WWVH
frequencies.
The United States National Institute of Standards and Technology (NIST)
operates two standard time and frequency stations in the shortwave bands. Radio station
WWV is located at Fort Collins, CO, while WWVH is located at Maui, Hawaii. These
stations appear on frequencies of 2.5 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz. You
can identify WWV by the male announcer and WWVH by the female announcer. In
some locations, or on some occasions, both WWV and WWVH are audible at the same
location. These stations give one-second ticks, followed by a voice announcement every
minute that gives the exact time in Universal Coordinated Time (UTC). These
announcements may be used to determine the current time to the second when setting up
some of the clocks.
The Ten-Tec PC Radio shares a single serial port with other functions. Only one
application may use the serial port at a time. To use the radio, all other applications using
the serial port must be terminated and the serial port selector must be switched to the
Ten-Tec PC Radio. Once the application is running, various WWV frequencies may be
scanned for best reception.
127
Procedure
Step 1 PowerChute PLUS is a program that monitors the UPS. This program is
usually running, and it requires use of the serial port. Check to see if PowerChute PLUS
is running on the PC. It may be iconized at the bottom of the screen (FIG.1). If it is
running, the Status will indicate On Line, as shown in FIG. 2.
PowerChutePLUS
icon
FIG. 1 View of PowerChute PLUS icon
128
Status: On Line
FIG. 2 View of PowerChute PLUS when program is running
129
Step 2 If PowerChute PLUS is running, quit the application by clicking in the X
in the upper right-hand corner (FIG. 3).
Interrupt on X to quit
program
FIG. 3 Location of X to quit the PowerChute PLUS application
130
Step 3 If the PowerChute Plus Program was running, you also must terminate
communication with the server via the PowerChute Plus Server window.
The PowerChute Plus Server window can be opened via the Window's Start
menu:
Start → PowerChute PLUS_Windows → UPS Monitor.
This will open the window shown in FIG. 4
If communication with the server is still established, it will be indicated by:
*** PowerChute PLUS Version 4.2.2 Started ***
Communication established
FIG. 3 PowerChute Plus Server window
131
Step 4 To terminate communication with the server, click on the X in the upper
right-hand corner of the PowerChute Plus Server window as shown in FIG. 5.
Click here to terminate
communication with
the PowerChute Plus
Server
FIG. 5 Location of X to terminate communication with server
132
Step 5 A dialog box will open (FIG. 6). Click on EXIT to quit monitoring.
Click on
EXIT
FIG. 6 Location of EXIT button to quit UPS monitoring
133
Step 6 Switch the serial port switch to position "D", PC RADIO as shown
in FIG. 7
Select
"D"
PC RADIO
FIG. 7 Serial port switch
134
Step 7 Startup the Ten-Tec PC Radio program via the Window's Start menu:
Start → Program → Ten-Tec PC RADIO → Ttrcx → TenTec Radio Control.
The window shown in FIG. 8 should open.
FIG. 8 View of the Ten-Tec Radio Control Panel
135
Step 8 Click on TIME/UTC to open the window that presents a selection of
WWV frequencies (FIG. 9).
TIME/UTC
menu
FIG. 9 Location of TIME/UTC button used to open a window to select WWV frequency
136
Step 9 Select desired frequency from selections shown in FIG. 10 (15 MHz often
works well during both day and night). The frequency is changed as soon as you
interrupt on the frequency, so it is possible to try out several frequencies to determine
which provides the best reception.
Select a
frequency
FIG. 10 Location of US (WWV/WWVH USA) or Canadian (CHU CANADA)
frequency selections
137
Step 10 When you are satisfied with your frequency selection, click on Exit and
Keep Changes (FIG. 11) to return to the Ten-Tec Radio Control Panel.
Click on
Exit and Keep Changes
FIG. 11 Location of Exit and Keep Changes button
138
Step 11 When finished using the radio, exit the Ten-Tec Radio Control Program
by clicking on the X in the upper right-hand corner (FIG. 12).
Click on X
FIG. 12 Location of X used to terminate the Ten-Tec PC Radio Program
139
Step 12 Switch the serial port switch to position "B", UPS 2 as shown
in FIG. 13.
Select
"B"
UPS 2
FIG. 13 Serial port switch
140
Step 13 Reestablish communication with the serial port for the UPS monitoring
program by selecting
Startup → PowerChute PLUS_Windows → UPS Monitor.
The window shown in FIG. 14 should open. If communication was successfully
established, it will be indicated by:
*** PowerChute PLUS Version 4.2.2 Started ***
Communication established
FIG. 14 Window indicating communication with the serial port used for UPS
monitoring was reestablished
141
Step 14 Restart the PowerChute Plus application via the Window's Start menu:
Start → PowerChute PLUS_Windows → PowerChute PLUS.
If the program has successfully started, it will be indicted by Status: On Line, as
shown in FIG. 15. To iconize the display, click on the iconize button shown in FIG. 15.
Status: On Line Iconize
FIG. 15 View of Power Chute PLUS window when UPS monitoring program is running.