GARMIN 196 QUESTION

Hi, I just bought the Garmin 196 and I really think its great.. only
problem
I seem to have is satellite aquisition times and if any at all. I have
turned it on in various locations and sometimes receive no aquisition at
all, and sometimes I immediatly get it. I even turned it on in flight to
no
avail.. It seems the "stick" antenna is not strong or working at all... Is
this me or do others have the same problem? Even on the Ramp of my home
airport it seems hard or a long time to aquire a satellite fix.. any help
appreciated ...

Mike,

I am not sure what you consider a long time. It might be a problem with
your box or it might be a matter of expectations. When you turn on the GPS
go to the satellite page. Keep your hand off the antenna, the GPS signal is
a 50 W signal in an 11,000 mile orbit! Before the GPS receiver can use the
satellites, it has to know where they are. There are two sets of data,
almanac and ephemeris. Consider the almanac as a rough listing of where the
satellites are and the ephemeris as fine data about the individual orbit.
Each satellite broadcasts the almanac and its ephemeris. If I remember
correctly, the almanac is good for about 30 days and the ephemeris is good
for a couple of hours.

You should start to see hollow signal strength boxes pretty quickly. This
means that the satellite is being received, but that it is downloading the
ephemeris data. Once the bar goes black, the GPS has the ephemeris data and
the satellite can be used for navigation. You will have to have 3 satellites
before you can have 2-D navigation and 4 satellites for 3-D.

If you turn the GPS on and there is no almanac, it will take several minutes
to download the almanac and ephemeris data. If you turn the GPS on with a
current almanac, but it has been long enough to have different satellites in
view, it will take a few minutes. If you turn the GPS on and it has been
very recently turned off so that it has current ephemeris data on a
sufficient number of in view satellites, the GPS will get a position very
quickly.

Also important is antenna location. The aircraft structure will block the
signal. The better "view" of the sky the antenna has, the better luck that
you will have. Also, as one of the later responses mentions, the external
antenna is also a little better than the stick antenna. Consider how much
sky the antenna can see from its location. For example, if you were to use
the stick antenna on the yoke mount of a high wing airplane, you would be
lucky to get a signal. However, the external antenna on the glareshield or
high on the windshield should be adequate.

Here is more info on the initial start:
http://www.gpsinformation.org/dale/gpsfix.htm

Also, I have a book on using GPS at www.cockpitgps.com. My book is a free
download. If you find it useful, my minimum but still acceptable payment is
that you sign my guestbook.

Hope this helps,


John Bell