what kind of coax are you using?
what are you using to measure swr?
are you sure you made a good connection to the coax?
I got a 500' roll of 1/2 price coax at a HAMfest a couple of years ago, the shielding was so terrible, at 40m it was leaking RF, 6m was completely unusable. At the higher frequencies (10m), the coax plays a bigger role than, say 75m. This stuff wasn't 100% shield, and we absolutely could not tune a 6m mobile antenna with it. 6-8' in length! When we switched to 100% shielded coax, the difference was immediate.
KJ4ADN - Bill