Re: ubitx LPF #bitx20help #bitx40help #ubitx #bitx40 #ubitx-help

Ian Reeve

The spacing between turns,the number of turns,the wire diameter and the type of torrid all have an effect on the inductance. I use one of the "cheap" inductance meter and the readings are very close to a instrument costing nearly £100 so for me the inexpensive   one is good.

From: <> on behalf of hickmodawg@... <hickmodawg@...>
Sent: Saturday, November 2, 2019 8:05:28 PM
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Subject: Re: [BITX20] ubitx LPF #bitx20 #bitx20help #bitx40 #bitx40help #ubitx #ubitx-help

Why not use the online calculators to get an estimate of the number of turns we need, and then use an inexpensive meter to fine-tune the number and arrangement of windings before installing the toroid on the board?  I got a cheap LC100-A meter on EBay that measures inductance and I was a little shocked to see how the inductance values of my toroids changed just from moving the windings closer or farther apart, not just from adding or subtracting winds.  It seems to me, that the size and composition of the toroid, and the spacing of the windings may have an effect on the resulting inductance, not just the number of windings.  I’m really still quite new to this, but, I’m wondering, why not use a meter before installing our toroids onto the board?  Is it because these cheap meters are very inaccurate?
Martin, AJ6CL

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