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Old 9th Oct 2019, 5:49 pm   #35
paulsherwin
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Join Date: Jun 2003
Location: Oxford, UK
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Default Re: Ferrite rod antenna and RF amp for Valve radios

Quote:
Originally Posted by Christoffrad View Post
Paul
Thank you for your circuit. I note that your antenna uses a tapped single coil. The antenna I have uses two discrete windings a primary tuned winding and a isolated coupling coil.
You can wire a coil with an overwinding to work as a single tapped coil. It's only for impedance matching, and one arrangement is pretty much the same as the other. I just happened to have a tapped coil when I built it (from a scrap transistor radio).

Your circuit doesn't show a cap to decouple the battery, which just might be significant. Try 0.1uF or a small electrolytic (or both).
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