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| Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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28th Mar 2024, 7:39 pm
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#1 |
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Hexode
Join Date: Oct 2007
Location: Ossett, West Yorkshire, UK.
Posts: 408
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Identifying Unknown Radio Coils
Hi folks,
I've collected loads of radio coils over the years many of which are Wearite and Denco. A few years ago I got a box of bits at car boot sale which included loads of radio coils which I'd like to identify. I've taken photos and measured inductances and hope some of you will recognise the coils. Photos to follow! David |
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28th Mar 2024, 7:45 pm
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#2 |
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Hexode
Join Date: Oct 2007
Location: Ossett, West Yorkshire, UK.
Posts: 408
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Re: Identifying Unknown Radio Coils
Three coils, not Wearite but similar and labelled Aerial and Oscillator.
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28th Mar 2024, 7:48 pm
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#3 |
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Hexode
Join Date: Oct 2007
Location: Ossett, West Yorkshire, UK.
Posts: 408
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Re: Identifying Unknown Radio Coils
A Wearite coil but it only has 3 contacts and the former is shorter than a Type P coil photographed alongside.
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28th Mar 2024, 7:52 pm
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#4 |
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Hexode
Join Date: Oct 2007
Location: Ossett, West Yorkshire, UK.
Posts: 408
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Re: Identifying Unknown Radio Coils
Unknown coil possibly out of a radio?
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28th Mar 2024, 7:58 pm
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#5 |
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Hexode
Join Date: Oct 2007
Location: Ossett, West Yorkshire, UK.
Posts: 408
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Re: Identifying Unknown Radio Coils
Two coil formers with multiple coils on them. One is faintly labelled Aerial, the other labelled "Osc".
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28th Mar 2024, 10:42 pm
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#6 |
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Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,198
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Re: Identifying Unknown Radio Coils
Hi David, plenty of those coils were used in commercial sets. they can be identified by looking at typical circuits and a resistance measurement of the windings to identify coupling and tuned winding.
To determine the range you can parallel the tuning winding with either a 500pF or a 365 PF cap. Monitor with a scope and feed with a sig gen; tune for resonance. This will give LF end. repeat with about 20pF and determine HF end. You could also measure the inductance with one of the small inductance meters and again calculate using the above cap values Or, you can use a Q meter which will characterise the coil much better. The Advance unit is easy to use and is often seen on ebay. Last picture shows MW or LW coils. Sometimes they have 5 tags, with the tuned winding being tapped for wavechange. (production saving) Note that for SW coils the tuning cap will be a lower value, usually by means of a series cap to the main gang Ed |
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