Does Anybody Really Know What Time It Is?

Because our radio signals can go all of the way around the world, hams use Coordinated Universal Time (UTC) to keep track of our radio contacts. That way, if you send a QSL card to a ham in another country, he knows when the contact happened without having to deal with time zones. UTC is also referred to as Greenwich Mean Time (GMT) or just Zulu (z) time.

The table below derived from www.timetemperature.com shows the time offset for UTC from the time zones in the US. For example, if you live in central time zone, you normally add 6 hours to the local time to obtain UTC. Unless, of course, Daylight Saving Time (DST) is in effect, then you add 5 hours.

Time Zone in
United States

UTC Offset
Standard Time

UTC Offset
Daylight Saving Time

Atlantic

UTC – 4h

N/A

Eastern

UTC – 5h

UTC – 4h

Central

UTC – 6h

UTC – 5h

Mountain

UTC – 7h

UTC – 6h
* n/a for Arizona

Pacific

UTC – 8h

UTC – 7h

Alaska

UTC – 9h

UTC – 8h

Hawaii – Aleutian

UTC – 10h

UTC – 9h
Hawaii does not observe daylight saving time

Daylight Saving Time is a confusion factor for UTC, which is why I usually just check on UTC directly, so I don’t make a one hour error while offsetting my local time.

So how do you figure out what time it is in UTC? The old school way to do this is to listen to a shortwave station that broadcasts time information, such as radio station WWV. A more modern way to find the UTC time is to check the time.gov web site on the internet. Another trick is to just enter “UTC time” into Google or Yahoo and the correct time will be displayed.

GPS receivers are an excellent source of accurate time information because the positioning system depends on having precise timing between all of the system’s satellites. Just set the time zone on your GPS to “UTC” or “GMT” and it will read out in universal time.

There are a number of smartphone apps that display time in UTC, many of them free. I use HamLog by Pignology , which is a handy app that does a number of ham radio related tasks, including showing UTC. It costs 99 cents and is available on Android and iOS.

When I am doing anything ham radio related such as working a radio contest, I set my watch to UTC so I always have the right time in front of me. (It helps if your watch can display in 24 hour format.) My watch has multiple time zones, so I just set one of them to UTC while also keeping local time available.

If you are using a software logging program, make sure your computer is set to the right time. Most people keep their computer clock on local time. That means the logging program will figure out UTC by adding in the right offset from your computer’s local clock. But sometimes the computer gets it wrong, so double check it with another time source.

One of the tricky things to get right is the UTC date. Since UTC time is running ahead of us in North America, the UTC date will change many hours before the date changes here. For example, when it is late Saturday evening March 3 in the US, UTC time will already be Sunday morning March 4th. This is a classic error on QSL cards: getting the UTC time right but listing the wrong date. When the UTC clock rolls past 0000, you need to increment the day ahead (compared to your local date).

So there’s a few tips to help keep track of ham radio time.
73,
Bob K0NR

One thought on “Does Anybody Really Know What Time It Is?

  1. Pingback: This Spewed Out of the Internet #27 « KØNR: Radio Enthusiast

Comments are closed.