Thread: Receiver sensitivity
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Ralph Mowery Ralph Mowery is offline
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Default Receiver sensitivity
In article ,
says...

** But ( older) car radios had high impedance inputs on the AM band.
A short run of coax is a pure capacitor at AM frequencies.
The trim cap set the antenna coil to resonance while moving ferrite slugs did the actual tuning.

....


I don't recall the impedance of the car antenna coax, but it was special
low capacitance/high impedance . Most common coax for radios and TVs
are usually either close to 50 or 70 ohms and have about 2 to 3 times
the capacitance per foot as the car coax.

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