thebestofall007
New Member
I got another antenna for a 1996 Toyota Celica to replace its defective power antenna and while I now get good FM reception, I get poor AM (I can put a wire or my hand on the antenna and the AM reception improves, but then the FM degrades). I replaced the Toyota's antenna with a 95 Pontiac Grand Am OEM antenna I got from a junk yard that happened to fit perfectly to the mounts inside the Toyota's fender, as the Pontiac's OEM spring steel whip is much more durable than the (often) cheaply made replacements found at Wally world or elsewhere, fixed or otherwise, plus I hate power antennas (too much parts, plus much more expensive). I have had good results with 31" steel whips reception wise in other vehicles with both bands. I am using the Toyota's OEM cable. I have tried a different RG-6 TV cable (because it was thicker), no go, so I went back to the Toyota's OEM.
Something is telling me they might have used an in-line impedance matching/trimmer capacitor somewhere to compensate for the higher capacitance of a longer cable run or something, as the antenna on my Toyota is also rear mounted and its original antenna might have also had a cap. Would adding a ceramic capacitor to the center conductor of the coaxial cable between the radio and antenna fix this (and what value in Picofarads?), as I have heard that AM radio frequencies are picky about the capacitance of the cable and whatnot due to 31 inches being far too short for the lower frequencies AM uses but not FM, as per this thread in response #7: https://www.electronicspoint.com/threads/car-radio-antenna-has-an-inline-85mfd-capacitor-why.102193/
What can I do to remedy this?
Something is telling me they might have used an in-line impedance matching/trimmer capacitor somewhere to compensate for the higher capacitance of a longer cable run or something, as the antenna on my Toyota is also rear mounted and its original antenna might have also had a cap. Would adding a ceramic capacitor to the center conductor of the coaxial cable between the radio and antenna fix this (and what value in Picofarads?), as I have heard that AM radio frequencies are picky about the capacitance of the cable and whatnot due to 31 inches being far too short for the lower frequencies AM uses but not FM, as per this thread in response #7: https://www.electronicspoint.com/threads/car-radio-antenna-has-an-inline-85mfd-capacitor-why.102193/
What can I do to remedy this?
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