air inductor

There are several air coil online calculators on the Internet. Here is one of them:

http://eweb.chemeng.ed.ac.uk/jack/ra.../newcoil3.html

Using keywords 'air coil inductance calculator' will get several hits using Google for search.

For this small value you are better off copying a commercial model. http://www.coilcraft.com/smspring.cfm lists coils in this range. Just copy their number of turns and dimensions.

small value of inductance are often dominated by pin/lead lenght.

Identify the 2 nodes (or reference planes) where you have to place your inductor.

As rule of thumb, consider 1nH each millimeter of straight conductor.

Detract the inductance of the "distance" of the 2 nodes from the required one.

which with of track use.

I want to make air core coil of 7nH, then, do you mean that in my case i will put it just a wire of 7mm length?! If so, what diameter of cupper wire should i use? and will it be straight or bridged? .. what are other specifications should i put into consideration...

Please clarify it to me,
Thanks,
Ahmad,