From 
It is with great sadness that I write that the ON4UN signal has gone silent. John Devoldere was Mr. radio amateur, Mr. aerialist. Certainly many radio amateur libraries contain his book Low-Band DXing či zbierky QSL ticket. I have that book. In the printed version. Every piece of information in it is worth its weight in gold.
Podľa slov dcéry, Marleen Devoldere, otcovi sa posledný rok stav zhoršoval. V posledných týždňoch bol s nimi doma a jeho srdce dotĺklo 9.novembra. Johnovou celoživotnou láskou bolo amatérske rádio, bol pravidelným účastníkom svetových contestov aj uznávaných DX-manom.
The survivors are planning a digital farewell ceremony for Saturday, November 21. If you want to express your condolences, you can do so by writing to ON4UN.SK@gmail.com . Na ON4UN QRZ.com you will also find current information.
John, we will miss you, but trust that Your signal will continue to spread through the endless ether.