[time-nuts] How do I compare GPS antennas?
hmurray at megapathdsl.net
Tue Sep 5 22:23:59 EDT 2017
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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