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| Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members. |
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Thread Tools |
7th Feb 2009, 12:35 pm
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#21 |
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Rest in Peace
Join Date: Apr 2008
Location: Worcester, Worcestershire, UK.
Posts: 330
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Re: AM Modulation
The circuit I used was in the 6th Eddystone Short Wave Manual from the 1940s. It was for their "Short Wave Two". Only the values of the components would need changing for 'mains' valves. I would not vary the anode voltage only the screen. If you want the circuit details I can photo and put pic on.
As far as pop music and local radio is concerned I think it is only intended to make people deaf! Pat |
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7th Feb 2009, 6:19 pm
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#22 |
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Octode
Join Date: Jun 2004
Location: Hampton Vale, Peterborough, UK.
Posts: 1,698
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Re: AM Modulation
I'd certainly like to see that circuit, Pat, if you can be bothered to upload it.
-Tony |
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8th Feb 2009, 12:53 am
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#23 |
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Rest in Peace
Join Date: Apr 2008
Location: Worcester, Worcestershire, UK.
Posts: 330
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Re: AM Modulation
OK here it is. I will add the component values if you want them but the original is not very clear.
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8th Feb 2009, 1:37 am
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#24 |
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Rest in Peace
Join Date: Apr 2008
Location: Worcester, Worcestershire, UK.
Posts: 330
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Re: AM Modulation
Well here are the component values.
C1 60pF. C2 140pF. C3 13pF. C4 100pF SM. C5 & C7 0.002 mfd (I used polystyrene) C6 250pf ceramic trimmer. C8 & C11 0.47 mfd. C9 & C12 300pF. C10 0.01 mfd (ceramic or poly or mylar anything but paper!) R1 2meg. R2 30k. R3 & R9 1k. R4 100K ww pot (I used 47k). R5 & R6 47k. R7 470k. R8 10k. Designed for use with Eddystone 6 pin plug-in coils. Valves V1 KF35 V2 KL35. these are hard to find. I used 210SPT and KT2 which I had. The trimmer is set to initiate oscillation with the pot at mid point. Have pics if interested. Pat G3IKR |
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