[AMRadio] RE: the weekly receiver update

[Brett Gazdzinski]

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
> 
> 
>