ISSUE: Radio reception is exceptionally good at full strength, but it diminishes substantially with a loss of even 1-2 bars of signal srength.

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I just received my Rio Car tuner. I've hooked it up to my Isuzu VehiCROSS' antenna connector using the Rio-supplied antenna adapter.

I can receive most radio stations pretty well, with a "maximum" signal strength indicated. However, as I go up and down hills, or turn corners, often the signal strength will drop by 1-2 bars. Although it's probably normal to lose some strength as you make your way around town, it's probably *not* normal to have such a minor change be audible.

Even when the signal strength drops ONE bar from maximum, the sound become noiceably quieter. As the signal strength fluctuates -- even just 1-2 bars -- so, too, does the audio quality, and quite substantially I might add. I don't recall my OEM tuner behaving in this manner; it would tune radio stations with exceptional clarity unless the signal was extremely weak. Turning corners and going up and down hills did not cause audible distortion/depreciation of the radio reception.

Is this nromal tuner behavior? (i.e., is this tuner module just very sensitive/fussy?)

Or could I have hooked it up incorrectly? My car does NOT have a power antenna (i.e., my antenna is ALWAYS "up"). However, I still wired the blue "antenna" wire from the radio *tuner module* to to the "antenna control wire" on my car's wiring harness (I did not wire the *seemingly* redundant control wire from the docking sled, however, as I assumed the tuner module's control wire would acomplish the task). I did this because I suspect that my vehicle *might* have power amplification of radio signals. I'm led to believe this because:

a) the antenna is about half the length of a typical antenna, coated with plastic, and clearly has a wire wrapped around it underneath the plastic sheath, almost like a cellular phone antenna;

b) there was an antenna control wire indicated on the harness, so I figured it must be there for a reason;

c) the antenna plug behind the dash also had a couple wires going into the wiring harness.

The VehiCROSS is a limited-production vehicle that is built on the Isuzu Rodeo chassis, but still has some marked differences (i.e., no ground wire, for example - all components must be grounded to the chassis, even though a ground wire is (misleadingly) present on the harness). In other words, just because there's an antenna control wire on the harness, doesn't necessarily mean that it serves a purpose.

Any ideas? Thanks in advance for your help.