© Brooke Clarke,
N6GCE
Background
Heathkit offered a WWV & WWVH synchronized clock
(GC-1000) that was very sophisticated in that it also adjusted the
frequency of it's crystal when the signal was strong. See U.S. patent 4582434
Time corrected, continuously updated clock Apr.,
1986 Heath Company for more about this. The
RS-232 capability of the Heath clock was minimal and it had a 1 hour
error twice a year
when displaying local time because it switched to/from daylight savings
time when Colorado switched, not my local time.
The PST Model 1020 is a larger (11 1/2 w x 3 h x 11 d) unit that has
more computer interface capability including NTP capability. The
main PCB has a notch that's about 7" x 7" with a daughter board plugged
into the main board. The receiver proper is on the daughter board
so maybe they also offered different versions for WWVB or time stations
in other countries? It also has built in provision for not only
external
12 Volt main power but also for seperate 6 V Gell Cell backup power
with
trickle charge. The display includes both month & day as well as
hh:mm
in 1" digits and ss in 3/4" digits. The PST1020 uses software
tracking,
rather than crystal frequency adjustment, so that the clock keeps good
time
during those times when the signal is not strong enough to read the
data.
The PST 1020 has the same bug as the Heathkit GC-100, it changes
to/from daylight savings when Colorado changes, not in my time
zone. I have upgraded the ROM chip and as of 31 Octoer 2004 the
transition is correct. The 12 hour time format is
illogical. At midnight the DATE changes to from 30 Oct to 31 Oct,
and the time changes from 11:59:59 to 12:00:00, but 12:00:00 is not a
further hour on 30 Oct.! It should change to 00:00:00, which is what a
24 hour clock would do.
A few days ago (today is 9 Apr 2003) the 1020 lost lock and could
not re-establish lock, but did after a power down and restart. It did
this for two or three days in a row. But it now seems able to
work 24 hours a day which includes changing frequencies as the HF
propagation conditions change so maybe the problems of the last few
days are related to poor HF
propagation. Note that this problem of loosing lock for a couple
of
days is the main reason why HF was replaced with low frequency time
transfer
methods. (powered by an Agilent E3617A bench supply pulling maybe 400
ma
that fluctuates with the time being displayed.)
10 Apr 2003 - Connected my house 12 V storage battery to the PST1020 as
it's main power and this caused two strange behaviours, (1) every now
and
then (maybe 30 to 60 minutes apart, but not on a schedule) the sould
would
be "click" . . . "click"... then a sound like a ratchet being turned in
the free direction that lasted for maybe a second (very much like
cocking a double action revolver and then spinning the cylinder), and
(2) the dispaly would go blank for a second or two then come back with
the correct time. My house HF antenna is fed from a multicoupler
and the antenna feeding it has the coax shield grounded outside as it
goes through a lightning protector so the coax to the PST1020 is has a
grounded shield. The 12 V storage battery has it's negative
terminal connected to a copper ground rod. The input DC power
connection shows -12 above +12 implying a positive ground system.
I used a couple of BNC-5-way adapters with a 0.1 uF cap in series
with
both the shield and center conductor to DC isolate the antenna
connection.
This has not fixed the problem, now the cock&spin noise goes
along
with the display turning off.
The company name Traconex and/or Multisonics
also shows in relation to this receiver. These are companies that
are involved with traffic signal light controllers where time
synchronization would be a good thing.
U.S. Traffic Corp
now called Quixote may
or may not offer the receivers.
Model
1010 - is the receiver board from a 1020 with external power supply
and display
Model 1030 -
rackmount version of 1020
U.S. patent
4768178 High precision radio signal
controlled continuously updated digital clock
August 30, 1988
"Prior efforts have been made to provide a clock signal
receiver that receives the radio broadcast signals described above,
such as the system disclosed in U.S. Pat. No. 4582434.
However, the system in that patent is subject to locking onto a
noise-heavy signal rather than the desired signal; this is a major
fault because the NBS (now NIST) signal transmissions are subject to
serious noise problems. Further, the '434 patent lacks a sufficiently
reliable method of verifying accurate data reception."
When I connected the 1020 to my house HF antenna system and power it
locked up within a couple of minutes. Much faster than the
Heathkit clock that would take a long time.
Like the Heathkit, the PST uses DIP switches for setting options, but
unlike the Heathkit the PST switches have no labels making setting them
much more difficult. It was displaying Eastern Time not Pacific
Time.
U114 has a paper sticker labeled: 008-0002-000, V03.06.000,
0788.
The PTS1020 makes a ticking sound each second. This is probably
due to a now dry capacitor. I've disconnected the speaker.
7 March 2005 - I've been using this clock to mark exactly noon in order
to make a ceiling sundial.
On March 6 this clock displayed 12:00:00 but was a full minute
fast. This is very apparent by the distance of my mark from the
line of other "noon marks". So this clock is not 100% reliable,
even with the latest PROMs.
Bad Caps
26 July 2006 - Outside it's been in the
110 to 118 degree F. range for the last couple of weeks and yesterday
my wife left the window open in this room even though the air
conditioning was on and it got warmer than usual in here. The
clock display is flickering and if you notice how many segments are on
the flicker is deeper when more segments are on. So it looks like
there's one or more caps (probably electrolytic) that are going bad.
Data Fromat
The following data is from the Network Time Protocol (NTP)
web page describing some radio clock data formats.
PST/Traconex 1020 Time Source (WWV/H) (firmware revision V4.01)
WWV Broadcast Format
WWVH Broadcast Format
WWV/H Timecode Format
"ahh:mm:ss.fffs<cr>" "yy/dd/mm/ddd<cr>"
"frdzycchhSSFTttttuuxx<cr>"
T
C
D
A Q
poll: "QTQDQM"; offsets: T = 1, D = 24, Q
= 41, A = 37
a = AM/PM indicator (" " for 24-hour mode)
hh:mm:ss.fff = hours, minutes, seconds,
milliseconds
s = daylight-saving indicator (" " for 24-hour
mode)
yy = year (from DIPswitches)
dd/mm/ddd = day of month, month, day of year
f = frequency enable (O = all frequencies
enabled)
r = baud rate (3 = 1200, 6 = 9600)
d = features indicator (@ = month/day display
enabled)
z = time zone (0 = UTC)
y = year (5 = 91)
cc = WWV propagation delay (52 = 22 ms)
hh = WWVH propagation delay (81 = 33 ms)
SS = status (80 or 82 = operating correctly)
F = current receive frequency (4 = 15 MHz)
T = transmitter (C = WWV, H = WWVH)
tttt = time since last update (0000 = minutes)
uu = flush character (03 = ^c)
xx = 94 (unknown) (firmware revision X4.01.999
only)
note: alarm condition is indicated by other
than "8" at A, which occurs during initial synchronization and when
received signal is
lost for an extended period unlock condition
is indicated by other than "0000" in the tttt subfield at Q
example: " 15:36:43.640
91/08/04/216 O3@055281824C00000394"
Links
Patents
related to Disciplined Oscillators -
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