[time-nuts] Comparing PPS from 2 GPS units

Jim Lux jimlux at earthlink.net
Tue Dec 18 14:05:44 UTC 2012

On 12/17/12 11:21 PM, Hal Murray wrote:
>>>     Cond. Material  	Magnet Wire Helix
>>> (What is "magnet wire", and what does "helix" mean and how does it effect
>>> coax?)
>> Magnet wire is enamelled wire (usually copper).
> I'm familiar with that usage, but I don't know why it's interesting in the
> context of coax.
> I think the key idea is that the insulation is thin so you can get lots of
> turns/inch in a transformer.
> I don't understand what a "helix" is in coax, or rather I don't appreciate
> the numbers.  I'd guess that the "center conductor" is constructed as a helix
> and that increases the inductance/meter by a whole lot, or something like
> that.  But isn't there a sqrt in there?

That is exactly what is done.. a *very tiny* wire is wound in a helix 
around a core (sometimes ferrous) that forms the center conductor of the 
coaxial cable, so it has huge L per length.

And yes, 1/sqrt(LC) is the propagation velocity


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