Hard to say based on one observation. It's equally likely the champ has a problem. Besides having your antenna grounded, does it have a ground plane? It doesn't have to be a continous disk of conductive material under the antenna but should be more than just a fuselage tube. There are numerous ways to acheive this. The simplest consists of using conductive copper tape on the back side of the fabric to create a well grounded asterisk, if you will.
If it were me, I'd gather more data by flying outbound from a known good ground station (FBO) and get some radio checks. When the signals get weak you could orbit and see how it is from different angles.