[time-nuts] T-bolt elevation error...

Didier Juges didier at cox.net
Sun Mar 30 11:02:16 EDT 2008


No because the GPS receiver takes into account the signals from more than
one satellite. What matters is the relative phase of these signals as they
reach the antenna. The relative phase of these signals does not change as
the signals go down the cable. The delay in the cable is inconsequential as
far as determining position, it simply creates an offset to UTC. 

Timing receivers typically have a provision for inputting the cable delay so
that their timing is also correct.

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Michael Baker
> Sent: Sunday, March 30, 2008 7:51 AM
> To: time-nuts at febo.com
> Subject: [time-nuts] T-bolt elevation error...
> 
> Hello, All--
> 
> Just for the sake of illustration, lets suppose that the 
> antenna is on my roof 20 feet above the ground but that it 
> took 150 feet of cable to get to the receiver.
> 
> Presumably, with no other information, the determined 
> altitude would be offset by the delay in the cable giving a 
> 130 foot error?
> 
> It would seem natural that the receiver would be (should be?) 
> able to be told how long the antenna cable is so that it 
> could factor out the delay.
> 
> However, I do not see any place in any of the control panels 
> to input a cable length correction.
> 
> Mike Baker
> WA4HFR
> Micanopy, FL

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