Pressure cook Radish slices, onion & toor dal along with turmeric to 2 whistle.
Meanwhile heat eat coconut oil in pan, roast channa dal, urad dal, coriander seeds, jeera, fenugreek seeds, low spiced red chillies & curry leaves until lentils turns little brown.
Transfer all roasted ingredients to blending jar along with coconut & grind to coarse paste.
Next add the cooked ingredients & grind paste to kadai. Add water as per your desired consistency.
Now add tamarind paste, jaggery & salt to taste.
Bring it to boil for 10-12 min in a medium flame.
Lastly heat a tsp of coconut oil/ghee in tadka pan, when it is hot add mustard seeds & let it splutter. Add hing & curry leaves. Pour this over prepared sambar.