[time-nuts] How do I compare GPS antennas?

Hal Murray hmurray at megapathdsl.net
Tue Sep 5 22:23:59 EDT 2017


Was
  Subject: Re: [time-nuts] GPS Antenna Feed Line Decision

kb8tq at n1k.org said:
> There is pretty much no experiment you could run that would show a
> difference  between the two. With a normal GPS, the “front end” of the radio
> is in the antenna. The filtering and RF amplification there determine a lot
> of things. The cable is just a  chunk of wire in the middle of the system.  

Does that depend on the antenna (and location) being "good" and both coaxes 
being good-enough so that the receiver always has a good signal?  
Alternatively, if the signal is good, you can't tell the difference in a few 
db of attenuation.

But suppose the antenna location isn't good.  How can I tell if it is 
good-enough?  Or how can I compare location A with location B?

The best I have been able to come up requires two identical receivers.  You 
can verify that they are identical, or at least close enough, by running them 
from a single antenna with a splitter.  I haven't gotten past that.

Assuming you had a not-good antenna, is there any numerical scale that would 
be useful to describe its goodness?


-- 
These are my opinions.  I hate spam.





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