Ko esprit 4 - reception / range fault

[westyrc]

i bought a ko esprit 4 a few weeks ago and I'm having a few issues. I can't seem to narrow it down fully basically the car will randomly lose reception from the radio and cut out after a few metres, I changed receiver and didn't have a problem. Got another car out last night to put a pack through it completely different new receiver in the 4wd car and that then did it but problem went away . I'm leaning towards a transmitter aerial issue. Anyone had any issues with the aerial ???