In article <79n9l8F1rmurgU1@mid.individual.net>, 
lumpy@digitalcartography.com says...

nospam@notreal.com wrote:

I wouldn't think one time zone could have two possible dates. I would
think it could get real confusing.  How could 9:00 AM 6/14 be the same
point in time as 9:00 AM 6/15 just because you put a different letter
with it?

It isn't/doesn't.

Zulu +12 (MIKE) is west of the Intl Date Line,
Marshall Islands, Wake Island, parts of easternmost
Russia.

Zulu -12 (YANKEE) is east of the Intl Date Line,
A couple of islands near the tip of Alaska.

After looking at several time zone maps on the web, it appears there is 
a time zone that is split in half by the date line in some places, 
giving rise to +12 and -12 to get the right date.  I missed that from 
looking at the ARRL world map on my wall.  Except for Chatham Island 
with its odd time, it only shows -12 west of the Date Line and +11 east 
of the Date Line so you would assume when your crossed the Date Line, 
the time also changed by an hour so you wouldn't need the extra time 
(date) zone.  I was led down the garden path so to speak.  My mistake 
and my apology.  

All that being said, as far as I am concerned the military should use Z 
time for all time that isn't local, and where there is the need to 
coordinate time across time zones or avoid confusion on the radio.  

As you say, and demonstrate below, the local time doesn't always agree 
with the standard time for a particular time zone, so if you are going 
to do something different why not choose to use Z time and be done with 
it. Everyone will be on the same page without doing any calculations.  

In addition, if the local time does not agree with the standard time for 
a particular zone, you are introducing a third time by introducing a 
standard time.  You either use either local time or Zulu time - period.  
If the world aviation industry can get along with just Z time and local 
time, why not the military.

I guess they have their reasons and that is real fine with me as long as 
I don't have to march to their drum :-).  
  
 

As I type this it's 1512 hrs zulu, Monday 15 June.
And it's 0812 hrs local (-7 TANGO) here in Phoenix.

In the Marshall Islands (+12 MIKE) it's 0312 hrs
Tuesday 16 June.

And at Howland Island (near Alaska, -12 YANKEE)
it's 0315 hrs Monday 15 June.

I don't see how say 9:00 AM Q is any better than saying 9:00 AM EST -
or is that 9:00 EDST?

The alpha designators for time zones are independant of
daylight savings time. New York is -5 (ROMEO). If it's
daylight savings time (as it is now) you would say
"JULIET is ROMEO PLUS ONE" to indicate that it's
1 hour shifted to the positive (-4 instead of -5).

JULIET in military alpha designators is local time
of the troops. ie "ADVISE JULIET" means "tell me what
time it is there in your area"

The reason ZULU = GMT/UTC is that ZULU starts with Z
as does ZERO. GMT/UTC is at ZERO longitude.

Terms like EST or EDST are local political conventions.
The Eastern Bumphukia Parliament may choose to rename it
to anything they want with each new dictator. Plus you could
(and do) have the same time zone in several political areas.
-4 QUEBECK could be called one thing in Venezuela, something
else in Paraguay, Greenland etc.

Instead of re-educating the entire military about new names for the
same thing, and learning a dozen different labels depending on
which lattitude you're at,  it's simpler to give it a ONE alpha
character designator.

It's also more accurate to communicate.
EST, GST, BST, TSV, DSB might all sound close on the radio.
QUEBECK is QUEBECK.

Confused yet?..;-)

Not all places are on the same minutes past/before the hour.
There's nothing from keeping any political body from deciding
that when it's 1300 zulu, it's 1745 there in their local country.

Nepal, Sri Lanka, Iran, India, Parts of Australia,
Newfoundland and others are all on "non even hours".
Iran, for example, is zulu +3:30. When it's 0700 hrs
in Greenwich, it's 1015 hrs in Iran. Iran doesn't have
DST because Ahmadinejad abolished it.

There is an island in Australia that has
daylight savings time but it advances it's
clocks only 30 minutes, not a full hour.

There are parts of Australia that, within the same
time zone, the northern areas do not observe daylight
savings time while the southern areas, in the same
longitudes, do observe DST.

"Daylight Savings Time" is not a universal name.
Parts of the world call it "Summer Time".

Right here in Arizona, we don't observe DST.
But the Navaho Indian reservation (within AZ)
does observe DST. BUT the Hopi Indian reservation,
which is WITHIN the Navaho reservation, does not
observe DST.


Lumpy

In Your Ears for 40 Something Years
www.LumpyMusic.com