Mr Baker found the gold ring while out metal detecting in a field near Bridgnorth in 2005. Inscribed on the ring were the names Mary and Sarah Littleton and the date June 7, 1735.
He did his own research and discovered that the ring, which has a rock crystal, was made by Thomas Littleton in memory of his wife Mary and their child Sarah, who had died in childbirth.
Mr Baker, 66, will tell the tale of the ring on ITV's Britain's Secret Treasures on an episode due to be screened on October 31.
"I was fascinated by the mourning ring and started to trace its history with the Shropshire County Record Office," said Mr Baker, who lives in Oak Avenue in Newport.
"I was able to find out quite a lot about the family. Thomas Littleton was a curate at St Leonard's Church in Bridgnorth for 60 years. He was also a vicar in Oldbury Wells for 50 years.
"He lived from 1703 to 1793 and went to Cambridge University. He had this ring made after his wife and child died in childbirth.
"He was a wealthy man and when he died he left a lot of money to Oldbury Wells and Bridgnorth.
"I have been detecting for 45 years and have found a lot of coins and artefacts – but this was the most interesting and historically important thing that I've found."
But Mr Baker, who is a member of Newport History Society, is not looking forward to his television debut.
"I just hope I've come across okay and have told the history of the ring well," he said.
* Britain's Secret Treasures is presented by journalist Michael Buerk and historian Bettany Hughes. It airs on Thursdays on ITV at 8.30pm.