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Mr 1936 · 22nd Sep 2022, 5:07 pm

Hi

Car radios use inductive tuning because:

It is physically smaller

It is electrically more suited to a short rod antenna. In a traditional design the first tuned circuit has a fixed parallel capacitor made up of the capacitance of the antenna, plus a short length of special low capacitance coax, plus the aerial trimmer, plus a fixed value. Since the first two are outside the control of the designer, the trimmer is used to ensure alignment.

Since FM came along this has all gone out of the window, and a FET preamp with no trimmer is used.

22nd Sep 2022, 5:07 pm	#33
Mr 1936 Heptode Join Date: Mar 2017 Location: Romsey, Hampshire, UK. Posts: 524	Re: My Latest Junker. Courier AM Car Radio. Hi Car radios use inductive tuning because: It is physically smaller It is electrically more suited to a short rod antenna. In a traditional design the first tuned circuit has a fixed parallel capacitor made up of the capacitance of the antenna, plus a short length of special low capacitance coax, plus the aerial trimmer, plus a fixed value. Since the first two are outside the control of the designer, the trimmer is used to ensure alignment. Since FM came along this has all gone out of the window, and a FET preamp with no trimmer is used.