I need some help - Antenna Warning on SWR Check

There's nothing wrong with the 102" antenna. But even this antenna may have an efficiency rating of around 70% on 11 meters when properly mounted. This is due to radiation resistance (electrical length not physical) of the antenna. I know that there's a lot of guys who have had to add a 4 or 5 inch heavy duty spring to get the swr reading they were after. I assume the reason for that was due to a lack of ground plane problem, like antenna mounted on rear bumper. Location location location seems to apply to 1/4 wave mobile antennas as well as real estate.

 

A 102" antenna will often require the ~6 inch spring to get the total electrical length to 108" for resonance.