[Lowfer] Ground cold end of coil?

[Eric Smith]

In pictures like this:  
http://www.highnoonfilm.com/xmgr/drawings/variometer.gif

and this: http://www.highnoonfilm.com/xmgr/drawings/antennacoil1.gif

it looks as if the cold end of the coil is grounded.  Is this right?  

In these pictures they are using coax.  The center lead is on one of the 
taps and the shield is attrached to the bottom of the coil which is 
grounded.

In my case I just have a piece of 22 gauge solid coming off the protoboard 
and alligator clipped to a tap.  The only ground is a coming off the 
ground rail of the protoboard and goes to the water faucet.  My coil is 
not grounded.

Should the cold end of my coil be grounded?

Thanks,
Eric