Re: Ferrite antenna advice for LW


John, older transistor radios have a low-impedance NPN (or PNP) RF amplifier and needed a low-impediance coupling coil on the ferrite.
Modern DSP radios have a high impedance FET RF amp in the IC, usually with auto-tuning of the high impedance ferrite winding.
If you use an exterior loopstick inductively coupled to the internal ferrite, it needs manual tuning with a variable capacitor. This is the
principle of theĀ  excellent FSL series.


On 19/06/2022 11:15, John wrote:

Thanks for your reply, I have read your articles and I will definitely try this. I am curious as to why your loopstick works with only a single coil - my understanding of traditional AM receivers is that they have a primary and a secondary coil which are coupled via the tap to the radio circuit. Do DSP radios work differently to analog radios in this respect? Many thanks

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