[AMRadio] RE: the weekly receiver update

[Mike Dorworth]

well you could put the wire in the oven, get it pretty hot, use welding
gloves, hook one end in a vise, roll form tight as possible, as fast as
possible while walking towards the vise, a rig with a barbque spit motor
would help, use heavy wire number 20 guage ?use a hartley osc so the coil
will be small, I wonder if the factory uses a current passed through the
wire to heat it.lotsa luck,, 73
mike k4xm
----- Original Message -----
From: Brett Gazdzinski <brett.gazdzinski at wcom.com>
To: <amradio at mailman.qth.net>
Sent: Saturday, April 06, 2002 9:49 PM
Subject: RE: [AMRadio] RE: the weekly receiver update


> Mike,
> Yes, I read all that, but I have no idea
> how you are supposed to heat the wire and keep it hot
> as you wind it on a small form.
> It takes me a while to wind one, and the forms are small
> and hard to handle turning it, keeping the wire tight,
> hot, etc.
> I used a bigger form and thicker wire, then put crazy glue
> on it....we will see how that works.
>
> I just tried this today, and noticed a lot of change while
> the glue dried.
> The coils are now all under the chassis in a shield
> box as well, so I will have to see if that changes things.
>
> I also got some pheonolic forms (on ebay) I can try
> if I still have the problem.
>
> I can also try reducing the plate voltage on the oscillator
> tube to see if less heat is generated in the coils.
> Its running at 105 volts now, but worked fine
> on 75 volts.
> The whole receiver seems to work fine at 75 volts!
>
>
> Brett
> N2DTS
>
>
>
> >
> >
> > There is some super information in the 13, 14, and maybe
> > even15th edition of
> > the Editors and Engineers Handbooks.Bill Orr was the editor
> > after the 13th
> > to the end. The two stable vfos used forms, one phenolic, one
> > ceramic, that
> > have the same temperature coefficients of expansion as the
> > wire. One used
> > very hot wire tightly wound so that when it cooled on the
> > form they were
> > one, the other matched the phenolic form with the other
> > componets for the
> > same effect...hope this helps, Mike, K4XM
> >
> >
> >
>
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