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winding the air coils


 

L1 4mm air core 3 turns .05 uH

L2 6mm air core 4 turns .1 uH

L3 6mm air core 7 turns .22 uH
is the dia inside or outside,ie do i wind l1on a 3mm drill bt and l2+3on a 6mm drill bit?.


 

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Traditionally, all air core inductors refer to the internal diameter, Paul. Wind them on drill bits. We have been doing that for many generations now.

Bill? VK7MX

On 1/12/2023 4:59 pm, Paul M3VUV wrote:

L1 4mm air core 3 turns .05 uH

L2 6mm air core 4 turns .1 uH

L3 6mm air core 7 turns .22 uH
is the dia inside or outside,ie do i wind l1on a 3mm drill bt and l2+3on a 6mm drill bit?.


 

cheers bill,do i use the same dia wire as i used for winding the toreroids? ?.


 

A good quest that all beginners ask. Inside diameter. Just use a metric drill of the correct diameter as the former.

Regards,

Ian,
VK2AZT


 

Hi Paul,
If you look at the schematic you posted a few days ago it states the wire diameters.
L1 = 0.5mm wire, L2 - L7 = 0.8mm
73, Dave


 

ive only just seen this,i already wound l1 with 0-8mm wire,will that matter,i mostly use the lower bands.


 

Hi Paul, The difference in inductance for such a small coil should be small, but you may find that the wire does not fit through the pad holes on the PCB.
73, Dave