UNIVERSAL TIME

When listening to a ham radio conversation or to announcements you often hear a reference to the time of an event and it may sound off beat. If you have spent time in the military or in aviation it probably won't be unusual; but for the majority , it will make you sit up and possibly wonder what is being referred to.

The subject of time can be very confusing. Standard time (Sun Time) Daylight savings time, Military time, Universal Time Coordination (UTC), Maritime bells, Railroad time, Greenwich Mean time (GMT)

Let try to simplify this mess. I often wonder how we teach a child to tell time when we as adults have complicated the subject so thoroughly. Well let's try.


Your Watch has an analogs face, 1 to 12. We Tell AM and PM by the Sun.

Your Bedside clock is probably a digital clock. Numerals are shown from 1 to twelve with AM or PM indicated by a red dot.
To this we add daylight savings time. Twice a year we change the clocks to help the farmers originally but later to save fuel supposedly. To accomplish this we should Fall back one hour in fall and Spring forward one hour in the spring. Now to complicate the situation we must change the clock to accommodate the sun so that it rises about 6 AM according to our clocks so we get to work on time. This gives us four time zones in the U.S.: Eastern,Central, Rocky Mt., and the Pacfic. If it is 9 AM Eastern it is 5 AM Pacfic This results in time zones across the world, need more, there lots.

Having the day divided into two equal 12 hour periods can create problems in communication. If someone asks you to meet them for coffee at 8:00 you might miss the appointment by 12 hours if you don't append AM or PM. To avoid this situation, Government agencies often use the 24 hour format. Here the AM times remain the same as the 12 hour format but instead of going to 1:00 Pm the 24 hour clock goes to 13 hours, 2:00 PM becomes 14:00 hours. This format is used by government agencies, police, and the Military. The Format changes with Standard and daylight savings so there is less confusion when working locally. You will find that some amateur radio nets are announced in the 24 hour format. A 7:30 PM net is announced as meeting at 19:30 hours. Frequently you will see the time written as 23:30:30 to be more accurate, The clock starts at 00:00 which is 12:00 midnight and runs through 23:59:59, twenty-three hours 59 minutes and 59 seconds.

When talking to an amateur radio station overseas hams will have to shift their thinking to UTC time as this is the standard. (Universal Time Coordination.) This is sometimes called Zulu or Greenwich Mean time (GMT) and some times Military Time. Here, we have one time zone, the world. The Clock still has 24 hours in it, and it starts 00:00 at Greenwich England at Midnight. When it is Midnight in England it is 7:00 PM, 19:00 on the east coast of the US. minus 5 hours Eastern standard time so the UTC time is 00:00 UTC Overseas military activities, Airlines, Multi National corporations and anyone who has to deal with time on a world wide basis soon finds this clock invaluable. No mistakes if everyone understand that they are working on Zulu (UTC) time. All international airports and control towers work on UTC time.
If you are reading a schedule of International radio stations, SW Radio (Voice of America, BBC) they all publish their schedules in UTC In amateur radio it wouldn't do any good to set up a schedule to talk to a friend in Java at 7:30 PM or 19:30 hours because he would not know the time difference but if you set up a schedule for 13:00 hours UTC conditions being right you could communicate.

Yes it is confusing but after you use it for a while you begin to think first in 24 hour time and then in UTC. Our brains are a wonderful thing.
It is no wonder that children have trouble learning how to tell time. Adults also, but it can be accomplished. Many ham shacks have a many as five clocks running, labeled what they are or a time in a foreign country. I am sure you have seen them in movies showing control rooms of one sort or another.

Many e-mails show the time in UTC. If you learn how to interpret it will add to your store of knowledge.