In a message dated 10/04/2005, dickthomas01@............. writes:
Chris has a point, too, about the computer we use with the detection
equipment. I doubt many of you use the newest computer to run WinSDR -- it is
overkill. But the older computers ARE slow to multitask and their clocks are not
that stable. I don't see Larry's GPS board that big an expense for the accuracy
it provides plus it is easy to install.
I might also add that variations in dependability in over-the-air reception
should be expected as well; there is day-to-night, sun spot interference --
even the arrival of long path-short path signals at the same time and place
can be a problem. There is also human created noise such as power generators
that carpenters use to power tools at construction sites, even legal amateur
radio broadcasting, broken insulators on nearby power poles and by all means
drift in the receivers being used to capture time pulses over the air.
In my limited experience, new computers seem to be even less reliable
for clock accuracy than older ones.
These seem to be more problems that I would associate with WWV signals.
WWVB may be a lot more reliable and my 60 KHz module has a crystal filter. I
have checked it for operation up to 1800 miles.
GPS is best for no other reason that it operates in frequencies above the
normal interferences -- it comes from straight up there -- with no bending over
the horizon
Assuming that you have clear vision to the satellites and no trees or
power lines in the way.... But GPS costs roughly 3x as much as a radio module +
aerial.
Regards,
Chris Chapman
In a message dated 10/04/2005, dickthomas01@............. writes:
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Chris has a point, too, about the compute=
r we use=20
with the detection equipment. I doubt many of you use the newest comp=
uter=20
to run WinSDR -- it is overkill. But the older computers ARE slow to multi=
task=20
and their clocks are not that stable. I don't see Larry's GPS board that b=
ig=20
an expense for the accuracy it provides plus it is easy to=20
install.
I might also add that variations in depen=
dability=20
in over-the-air reception should be expected as well; there is day-to-nigh=
t,=20
sun spot interference -- even the arrival of long path-short path signals=20=
at=20
the same time and place can be a problem. There is also human created=
=20
noise such as power generators that carpenters use to power tools at=20
construction sites, even legal amateur radio broadcasting, broken insulato=
rs=20
on nearby power poles and by all means drift in the receivers being u=
sed=20
to capture time pulses over the air.
In my limited experience, new computers seem to=
be=20
even less reliable for clock accuracy than older ones.
These seem to be more problems that I would=20
associate with WWV signals. WWVB may be a lot more reliable and my 60 K=
Hz=20
module has a crystal filter. I have checked it for operation up to 1800=20
miles.
<=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
GPS is best for no other reason that it o=
perates=20
in frequencies above the normal interferences -- it comes from straight up=
=20
there -- with no bending over the horizon
Assuming that you have clear vision to the=20
satellites and no trees or power lines in the way.... But GPS costs roughly=20=
3x=20
as much as a radio module + aerial.
Regards,
Chris Chapman