Any way to test a Spektrum rx, besides in a truck?

[tonkajeep34]

Been trying to get ahold of spektrum and haven't been able to so i thought I'd ask here.

I recently got a Spektrum DX3.0 with 3 sr3000 rxs. 2 work perfectly, the third was missing an antenna. I did a search and it looks like the antenna should be 8.5" so i put on a new one and threw it in the truck. rebound it and man it just acted all sorts of crazy.

so questions:

1. Is that the right antenna length?
2. any way to test and see if the rx is still good?
3. anyone know if spektrum will service the rx or am i going to have to replace it?

Thanks!