Radka is from the Czech / Slovak / Bulgarian Radka — diminutive of Radmila (rad — joy, care + mila — gracious) or Radana. Radka is one of the Slavic feminine diminutives. Her album Fairytales (1982, with Steve Dobrogosz) was voted best Norwegian record of all time by Norwegian music critics (2011).
Radka does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Radka reduce to 8, The Visionary. This is a traditional interpretive system, not a factual claim about the name.