[time-nuts] Trimble recommends RG-59 Antenna Cable.

[paul swed]

Its all been said above. Now I use zero loss ;-) 1/2" catv hardline 2 Ghz
stuff.
Regards
Paul

On Mon, Apr 30, 2012 at 7:33 AM, Bob Camp <lists at rtty.us> wrote:

> Hi
>
> Low noise receiver inputs are often mismatched to optimize noise figure.
> Receiving antennas may / may not be well matched to a given impedance. That
> all makes the mismatch loss a bit of a random thing. Some of the early
> Trimble docs mention that they saw essentially no mismatch loss when they
> swapped 50 ohm for 75 ohm cable.
>
> I'd strongly recommend that you use quad shield satellite TV coax rather
> than RG-59 though.
>
> Bob
>
> On Apr 30, 2012, at 2:23 AM, Robert Atkinson wrote:
>
> > Hi Ken,
> > This is correct. Some other documents explain the rationale. Basically
> for long runs the loss caused by the mismatch is less than the higher loss
> per foot of 50R coax of a similar size. Even better than RG59 is the high
> performance cable used for cable TV and satellite installations. This is
> cheap and low loss at 1.5GHz. This also also explains the F connector on
> the Thunderbolt. It would also be intersting to measure the actual
> impedance of some GPS receivers and antennas.
> >
> > Robert G8RPI.
> >
> >
> > ________________________________
> > From: Ken Kubick <kenkubick at hotmail.com>
> > To: Time Nuts <time-nuts at febo.com>
> > Sent: Monday, 30 April 2012, 6:58
> > Subject: [time-nuts] Trimble recommends RG-59 Antenna Cable.
> >
> >
> > Hi Time-Nuts guys,  I was reading the Trimble Thunderbolt manual section
> 2.1.3 (Antenna Cable).  Trimble recommends using RG-59 cable which is 75
> ohm coax.  Is this a typo or is this correct?  I thought that the Trimble
> Thunderbolt would use a 50 ohm cable and antenna.
> >
> > Thankyou
> >
> > Ken Kubick
> >
> > kenkubick at hotmail.com
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