🚀 go-pugleaf

My call for interest in building the new WWV/WWVH time code generators
has produced a total of one other enthusiast from the bushes.  He's on
the left coast and I'm on the right coast, but we're talking about it.

I got the spec from the procurement office.  It has 58 pages of legalistic
boiler plate, with many more pages included by reference, and 15 pages
of technical spec.  This has convinced me that it would be silly to
try to form the "Friends of WWV/WWVH, Inc." that I suggested to build
the TCGs.  The legalisms are far too intimidating for me.  But we might
just build them anyway as a gift to the government if there is no
bidder that they can afford.  It turns out the deadline for bidders to
reply is this Thursday.

Anyhow, here is a portion of the spec of direct relevance to NTP-ers.
It describes how the WWV/WWVH time code will be enhanced to deal better
with Daylight Saving Time and with Leap Seconds.  FYI.


[Excerpt from spec, Attachment 1 to Department of Commerce Solicitation
number 52RANB00C059, issued 1-23-90]

Attachment 1
Page 1 of 15

Revised 11/22/89

    SPECIFICATIONS

    TIME CODE GENERATOR/PROGRAMMER

1.0 Scope

    This specification establishes the requirements for two time code
    generator/programmer systems that will be used to generate precision
    timing signals for use by NIST standard time and frequency stations WWV
    and WWVH.  Each of these systems will consist of:

    (1) Three (3) time code generator/programmer units, and

    (2) Software and interfacing hardware to provide for entering commands
        to the time code generators through a computer.

[...]

2.5.6   Time Code Generator - BCD Format Table

    Second      Data

    00          low subcarrier
    01          0
    02          0
    03          0
    04          0
    05          0
    06          0
    07          0
    08          0
    09          position marker 1
    10          minute 1
    11          minute 2
    12          minute 4
    13          minute 8
    14          0
    15          minute 10
    16          minute 20
    17          minute 40
    18          0
    19          position marker 2
    20          hour 1
    21          hour 2
    22          hour 4
    23          hour 8
    24          0
    25          hour 10
    26          hour 20
    27          0
    28          0
    29          position marker 3
    30          day 1
    31          day 2
    32          day 4
    33          day 8
    34          0
    35          day 10
    36          day 20
    37          day 40
    38          day 80
    39          position marker 4
    40          day 100
    41          day 200
    42          0
    43  (new)   leap second warning
    44  (new)   Daylight Saving Time indicator #2
    45  (new)   year 1
    46  (new)   year 2
    47  (new)   year 4
    48  (new)   year 8
    49          position marker 5
    50          UT1 sign
    51  (new)   year 10
    52  (new)   year 20
    53  (new)   year 40
    54  (new)   year 80
    55          Daylight Saving Time indicator #1
    56          UT1 .1
    57          UT1 .2
    58          UT1 .4
    59          position marker 0

Note:   Daylight Saving Time indicator bits #1 and #2 are scheduled for
	change by the operator.  The normal procedure is for DST indicator
	bit #1 to change at 0000 UTC on the day of a change to or from
	Daylight Saving Time and DST indicator bit #2 to change in the same
	way 24 hours later at 0000 UTC on the day after the time change.
	When both bits are set to "0", standard time is in effect and it is
	not a day of time change; when both bits are set to "1", Daylight
	Saving Time is in effect and it is not a day of time change.  Each
	receiver can then interpret these bits unambiguously so as to change
	onto or off of Daylight Saving Time at 2:00 AM receiver local time.

Note:   Leap seconds are always inserted/deleted at the last second of the
	UTC month.  Leap second warning is scheduled to be turned on at any
	time during the month to which a leap second is being added, and is
	automatically turned off immediately after the leap second.  The UT1
	bits also automatically change after a leap second.  Incremental UT1
	changes may be scheduled by the operator at any time.

[End of excerpt from spec.]

Again, the above is the spec for the NEW generators, not what exists
today.  Today the DUT1 stuff doesn't change automatically, for example.
And there is no leap second warning or year info.

Not clear how a single leap second warning bit helps you when the
leap second is negative.  Does anyone know whether negative leap
seconds are expected to be needed in the next century or so?

/Rcc
Bob Clements, K1BC, clements@bbn.com