[HBR] IF transformers

[Peter Bertini]

Could well be...  I didn't expect to see that.

 But I suspect going beyond two cascaded in the first stage would give
diminishing returns regardless.  I'll let the Q-Multiplier supply the
CW selectivity. KISS.

Pete


On Sun, Oct 5, 2008 at 9:47 AM,  <Hopperdhh at aol.com> wrote:
> Pete,
>
> You can get into a situation where  the stray capacitive coupling can cancel
> the inductive coupling.  Maybe  that is what was happening.
>
> Dan K9WEK
>
>
> In a message dated  10/4/2008 2:36:21 P.M. Eastern Daylight Time,
> radioconnection at gmail.com  writes:
> Since I have several of these 85kc transformers to play with, I  tried
> two in cascade with good results. I tried several different  coupling
> cap values to couple the secondary of the 1st IFT to the primary  of
> the second one to see what effect the value would have on  the
> selectivity, and at what point the coupling became lossy.  Two  in
> cascade worked fine. I was curious, and added a third transformer,  for
> three in cascade. I ran into something odd: the two coils in  the
> middle IFT didn't seem to behave right; as if there was no  mutual
> coupling between them? This was even with the coils set for  max.
> coupling, close together. I don't understand what I am seeing.  Adding
> a small coupling cap from the high end of the primary to secondary  LC
> circuits in the second IFT solved the coupling problem.
>
> Pete
>
>
>
>
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