Courtesy of the ARRL:
On Saturday, April 18, radio amateurs worldwide will take to the airwaves to celebrate World Amateur Radio Day (WARD). It was on April 18, 1925, that the International Amateur Radio Union (IARU) was founded in Paris, with ARRL Co-Founder Hiram Percy Maxim, 1AW, as its first president. 
The primary purpose of World Amateur Radio Day is to highlight Amateur Radio and its benefits to countries and communities. The IARU said World Amateur Radio Day is an opportunity for IARU member-societies to demonstrate Amateur Radio to the public and make friends with other amateurs around the world. Special event stations will be on the air over the April 18-19 weekend to highlight World Amateur Radio Day and the IARU’s 90th anniversary.
“Since its founding, the IARU has worked tirelessly to defend and expand the frequency allocations for Amateur Radio,” the IARU said in marking World Amateur Radio Day. “Thanks to the support of enlightened administrations in every part of the globe, radio amateurs are now able to experiment and communicate in frequency bands strategically located throughout the radio spectrum.”
The 1925 IARU Congress in Paris. ARRL Co-Founder Hiram Percy Maxim is third from the right at the front table.
The 1925 IARU Congress in Paris
The International Telecommunication Union (ITU) has recognized the IARU as representing the interests of Amateur Radio. Today, Amateur Radio is more popular than ever, with more than 3 million enthusiasts around the world, the IARU has estimated. As 2015 will also mark the 150th anniversary of the ITU, the IARU has adopted the theme, “ITU & IARU: Celebrating 150 years of Advancing the Telecommunication Art” for World Amateur Radio Day 2015.
From 25 countries in 1925, the IARU has grown to include more than 160 member-societies in three regions. IARU Region 1 includes Europe, Africa, the Middle East, and Northern Asia. Region 2 covers the Americas, and Region 3 is comprised of Australia, New Zealand, the Pacific island nations, and most of Asia.
“April 18 is the day for all of Amateur Radio to celebrate and tell the world about the science we can help teach, the community service we can provide, and the fun we have,” the IARU said.
Who would be interested in a 3-part talk about digital modulation principles? Its aim is to provide a foundation from which digital techniques such as PSK31 can be better understood.
