Prime Meridian – Greenwich Mean Time

In most cases, amateur radio operators record the time of a conversation (QSO) as Greenwich Mean Time (GMT) or also known as Universal Coordinated Time (UTC).  Why?  No matter where in the world the amateur radion station is located, GMT or UTC is the time refrence by which all amateur radio QSOs are logged, doing so eliminates potential errors or misunderstandings of individual station time zones.  The same can be said for all emergency services radio communications and radio conversations between air traffic controllers and pilots of aircraft.  The time reference for all essential service radio communications is Greenwich Meant Time (GMT). The prime meridian serves as the world’s standard time zone

Today my wife and I visited the Royal Greenwich Observatory the location of the Prime Meridian at Zero degrees Longtitude (0).  Yep we are in London!   The prime meridian divides the earth’s Eastern and Western Hemispheres.  15 degrees west or east of the prime meridian marks a new time zone. 180 degrees opposite to the prime meridian (anti-meridian) is the International Date Line, a continuation of the prime meridian line over the North Pole to the South Pole and back.

Personally for me, visiting the prime meridian has been a long held ambition.  As luck would have it, we had boarded a River Thames cruise at Westminster which terminated at Greenwich.  Seriously, no prior planning on my behalf, but once at Greenwich finding the prime meridian was like searching for a geocache albeit well sign posted.  This is the ultimate geocache!

Below are photos of the prime meridian line at Longtitude zero degrees.  Just to prove a point, I activated HamGPS on my android phone which shows the Longtitude is -0.001 degrees at 102 metres ASL.

<strong>Photos:</strong> © Copyright 2016 Andrew VK1AD

No excuse for missing this sign

Greenwich prime meridian line (in the ground) showing reference to my home town Canberra (VK1), capital city of Australia at 149 degrees 👍.   No, Sydney is not the capital city of Australia.  😀

HamGPS showing -0.00 degrees, well almost.

Tick, prime meridian done.  In the future, each time I log a QSO in GMT, I will have fond memories of visiting Greenwich and the meridian GMT line.

After visiting the prime meridian the XYL and I had a proper pub lunch at the Greenwich Tavern.  From the menu we selected Haddock (North Sea fish) with chips and Sausages with mash spuds, bacon and crispy onions.

a local London Ale and lemonade

Fish and Chips & Sausages and Mash

73, Andrew VK1AD

This post was prepared on an iPad at 20160520 20:05 (Z)  (20:05 GMT)


3 thoughts on “Prime Meridian – Greenwich Mean Time

  1. Super interesting Andrew.
    GMT/UTC is also is known as ‘Z’ or ‘ZULU’ and the remainder of the world is broken down into appropriate letters as well.East coast Australis is ‘KILO’ (or LIMA during summer) so a time can be recorded as 0001Z or 1001K. Unfortunately half hour time zones don’t have a letter and are mostly referred to in ZULU time or JULIET (local time) as JULIET is not in the list.
    Hope ‘Walk the line’ one day.


  2. Hi Andrew, what an interesting post and great pictures. It looks like you are having a great time in London.
    John D

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