Re: More primary L needed

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Original poster: Ed Phillips <evp@xxxxxxxxxxx>


Hi All

I`v done the calc and I`v found that I need more primary to get the 
system to tune.
OK so adding more primary C is not an option also there is no room to 
add an extra
turn on to the primary, so I built a small inductor out of 14 turns 
of thick insulated
copper wire about 3" dia in the centre is a soft iron core made up of 
ferrous rods.

This plus the primary coil give just over the required inductance.

What are peoples thoughts on this ? method and construction.

Cheers Mike"

   Nothing wrong with using an extra inductor in the primary, but it 
will reduce the coupling.  In this case the "soft iron core" will 
probably overheat (the extra coil is nothing much more than a small 
spark-excited induction heater coil) and the losses will certainly be 
excessive.  Vary the number of turns but don't use an iron core.

Ed