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Install on xterra tubular roof rack
- Thread starter Ziploc
- Start date
First of all checking continuity with an ohm-meter will only tell you how good the ground is for DC or 0Hz, it won't tell you how good it is at 27MHz.
Secondly even if there's a good DC connection it is the roof rack which is being used as the RF ground, not the roof. The RF ground starts at the end of the coax and it is the metal directly underneath that matters and to the antenna system that's the roof bar, the roof would appear as a far removed ground plane which generally don't work that well.
Use an antenna analyser and see anything other than 36.8 Ohms at the antenna resonance (feedpoint impedance for a 1/4 wave ground plane over perfect ground) and you've got ground losses.