Message-ID: <000201c2115f$c33215c0$83e8fc3e@l8p8y6>
From: "hamilton mal" <g3kev.ham@virgin.net>
To: rsgb_lf_group@blacksheep.org
References: <5.1.0.14.0.20020611101143.00a7f1b0@gemini.herts.ac.uk>
Subject: Re: LF: DJ
Date: Tue, 11 Jun 2002 12:47:59 +0100
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----- Original Message -----
From: "James Moritz" <j.r.moritz@herts.ac.uk>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, June 11, 2002 10:39 AM
Subject: Re: LF: DJ


> Dear Mal, LF Group,
>
> At 19:59 10/06/2002 +0100, you wrote:
> >. Two taps on the coil permits freq adjustment from 135.7 - 137.8 khz...
>
>
> Something is wrong if you need to adjust the tuning within this range -
the
> output should be flat within a fraction of a dB  over the whole band
> without re-tuning.

Nothing wrong, I am fussy and like everything on the nose, and not bits of
dangling wire on the top of coils that you can wind one way or the other to
fudge an approximate resonance.
Perfection is my aim.

>
> Incidentally, an inductor that works OK for a low pass filter won't
> necessarily be suitable in this type of tank circuit - in the low pass,
the
> loaded Q of the circuit is usually 1 or less, depending on design, while
in
> the tank circuit it is about 6. This means the tank circuit  inductor has
> to cope with reactive power several times greater than the low-pass
> inductor for the same power throughput - so beware!

Mine runs ICE COLD. Surprised you have not tried this approach Jim instead
of using those big coils!!!!! and all that resistance !!!

G3KEV

>
> Cheers, Jim Moritz
> 73 de M0BMU
>
>
>