[time-nuts] Non-impedance matched antenna cables

[Bruce Griffiths]

Magnus Danielson wrote:
> Hi fellow time-nuts,
>
> For those of you that isn't aware of it, using 75 Ohm antenna cables rather
> than 50 Ohm cables is a bad move, as the antenna cable itself will create a
> multi-path system. This article elaborate on reflections i cables:
>
> http://tycho.usno.navy.mil/ptti/1998/Vol 30_39.pdf
>
> Nothing new, but needs to be said, especially with Thunderbolts getting more
> popular, as the manual clearly recommends 75 Ohm cable as I recall it. Do not
> listen to that.
>
> Cheers,
> Magnus
>
>   
Hej Magnus

If one uses cheap cable with relatively high attenuation at L1 this may 
not be a problem.
However the active antenna may need higher gain to compensate.
The question is just how much one way cable attenuation is required?

A considerable reduction in this effect can be obtained by making the 
cable length close to an odd multiple
of one-half the signal wavelength (½λ) in the cable.

Bruce