irampil@notes.cc.sunysb.edu wrote:
>
> Hi All,
> ...
> I am building it into the roof of the instrument module itself
> as I see no particular reason to string it into the rear of the
> fuselage. Is there any evidence, or anecdote that the GPS
> needs to be remote? I have tested it with two stainless plates
> approximating
> my through the firewall access panels, but have not put the panel
> with the antenna in the fuse yet.
The explanation for any such anecdotes would have to be proximity to
noise sources, avionics and spinning motors. GPS receiver sensitivity
is typically -135 dBm, like around 20 times more sensitive than any
other receiver in an aircraft. Plus another bad phenomenon where the
noise source is underneath the antenna. It is also a function of the
square of the distance - inversely, so mere inches count. I'd like to
try mounting it in the space inside the right side "shelf." There
would be some blockage of a satellite down toward 30-deg from the
horizon off the left side, and fwd thru the prop, but years of GPS
navigating seems to conclude that those sats - which GPS wants for
best 3-D, leaving 2-D working just fine, are practically useless (if
an altimeter is installed!). But still near to ignition noise
though. Has anyone tried that?
Regards,
Fred F.
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