[Lowfer] variometer design questions

[Mitch Powell]

 For example, I think Mitch's variometer is about 500mH and his
> primary is about 2 or 2.5mH.  Since my primary is so much bigger (7.8mH)
> does my variometer need to be 1.5mH or more, or would 500 be enough for me
> as well since I'll be tapping at some point near resonance and then just
> using the variometer to tune above or below that _slightly_, and not 1.5mH
> or more?

Take a look at the 1 mH coil I have added in series to my "main" coil.
Quickly wound up on a small  plastic bucket.



 Would this be better than the single layer coil on a
> form such as pvc pipe or whatever?

The PVC pipe route would be a solid, constant diameter form, and allow you
to drill a hole for the pvc or "broomstick" you will be using. I used a
small piece of bicycle tube rubber to make a tight fit for the variometer
tuning rod.... it is really tight.

I apologize for the rather rough construction - as it was experiment,
change, cut and running upstairs and downstairs many, many times to
get the tuning right.  But - as someone ( Peter ? ) said, you get it
to work and plan to "really clean it up and make it neat" but in the
meantime - ENJOY !

Pictures taken this week at

http://www3.sympatico.ca/m_powell/137coil.htm

73
and looking for you

Mitch VE3OT