Amateur station 9GM was licenced to Donald Anderson Kent of Dewitt, Iowa.
 
Radio Amateur News, February, 1920, page 421:
 
Station 9GM
KENT  BROS.  RADIO  STATION.

    The photo shows our radio station, 9 G M. For receiving we have a navy type coupler, audion detector, loading coils and condensers. The transmitting set consists of a Thordarson type transformer, sectional Murdock condensers, high speed rotary spark gap and oscillation transformer. With our receiving set we are able to get all the high power stations both ark and spark, also many amateur stations. We are about 150 miles from Chicago and enjoy the concert by wireless telephone from NUR every evening. As yet we have not done a great deal of sending but we get first-class results with our sending outfit.