Message-ID: <F1B0962410DF4A53BDE2D05E13F2D518@computereebf79>
From: "Martin Evans" <books@mollies.freeserve.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <593F4C0651144C339855AFC49ED4329E@computereebf79> <7.0.1.0.1.20120114082716.01cb5bf8@xtra.co.nz>
Date: Fri, 13 Jan 2012 21:23:19 -0000
MIME-Version: 1.0
Subject: Re: LF: Tuning inductance for 137kHz receive.
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Yes - I was given this tip by someone else yesterday, Kevin ( my apologies 
to the original tipster - I'm in another location now, and can't recall who 
it was!).

As you say, the problem is to find such a radio these days - though I'm 
certainly going to look out for one because 0.3mH to 2.8mH is an ideal range 
to have.

Martin.  GW3UCJ


##############################################


> Here is one effortless method that I have used for years to tune a random 
> wire for LF reception:
>
> First, find an old AM car radio that tunes with three ganged movable 
> ferrite slugs and extract the tuning unit.
> The three coils are all shielded from each other and can be series 
> connected in any order and polarity to maximise the total inductance. One 
> unit tested here allows continuous variation from 0.3mH to 2.8mH.
> On occasion, I have connected a fixed inductor in series to increase the 
> maximum possible inductance.
>
> I guess the major problem is to find a suitable old car radio - not 
> variable capacitor tuned.
>
> Kevin    ZL4MD
>
>