Garmin GpsMap 396 - Flight Test

By the way, this was with firmware version 2.8 which is what came on
the unit. I am planning to upgrade to 3.2 soon.

--Dan


Dan wrote:
I picked up a 396 on Friday and it was fine all the way from Phoenix to
Santa Fe, but lost it's sat signal during landing in Chandler....
Strange, but it seems I am not alone.


--Dan


wrote:
Mike Spera wrote:
30 seconds after take off, lost
the GPS sat lock. Took about 15 seconds to regain it. In the next 5
minutes, it lost lock several more times. I'm thinking, external antenna
is loopy.


Mike,

For what its worth...

I just flew my Arrow around the country and experienced the same
problem (with my brand spank'n new 396) that you described. Most of the
occurrences were in the takeoff or landing phase of the flight. I had
my old Lowrance airmap 100 on the copilot yoke and it never lost lock
once during the flight. The 396 was connected to the remote antenna
which was sitting on the glare shield, the airmap 100 was using it's
built in antenna.

-Bernie

My fly-about http://www.iperformax.com/flyabout/flyabout.html

I inquired to Garmin Tech support about our problems and got the
following response about clearing the almanac. Probably worth a shot.

--Dan


========================
Problem:
I had a problem with satellite reception over the weekend. In
disucssing this with other GPSMAP 396 users, including one who recently
upgraded to firmware 3.20, it seems they are experiencing similar
problems as well.
(i.e. intermittent GPS satellite loss) I have a GPSMAP 195 and have
never had a satellite signal issue. Is this a known problem? Will there
be a firmware fix?
===============================
Thank you for contacting Garmin.

As the GPS uses a satellite almanac of data to track the satellites,
corruption of this almanac will cause the unit to drop the satellite
signals. To correct(erase) the almanac, turn the unit off. Press and
hold the OUT button while turning the GPS on. When the GPS powers on,
release the buttons and let it acquire the satellite signals to start
rebuilding the almanac.

If you have any other questions, please let me know.

Best Regards

===================
Thanks. Would this likely resolve intermittent outages, or is this
only in the case of being completely unable to get a satellite lock at
all?

--Dan

================
Thank you for contacting Garmin.

As the unit contains data on all of the satellites and cycles between
all ones available, corruption of even one satellite's data could cause
the unit to have brief outages as it cycles through the list.

If you have any other questions, please let me know.

Best Regards
















Dan wrote:
By the way, this was with firmware version 2.8 which is what came on
the unit. I am planning to upgrade to 3.2 soon.

--Dan


Dan wrote:
I picked up a 396 on Friday and it was fine all the way from Phoenix to
Santa Fe, but lost it's sat signal during landing in Chandler....
Strange, but it seems I am not alone.


--Dan


wrote:
Mike Spera wrote:
30 seconds after take off, lost
the GPS sat lock. Took about 15 seconds to regain it. In the next 5
minutes, it lost lock several more times. I'm thinking, external antenna
is loopy.


Mike,

For what its worth...

I just flew my Arrow around the country and experienced the same
problem (with my brand spank'n new 396) that you described. Most of the
occurrences were in the takeoff or landing phase of the flight. I had
my old Lowrance airmap 100 on the copilot yoke and it never lost lock
once during the flight. The 396 was connected to the remote antenna
which was sitting on the glare shield, the airmap 100 was using it's
built in antenna.

-Bernie

My fly-about http://www.iperformax.com/flyabout/flyabout.html

Awwww right! I learned something here.. Who says Usenet is useless...

denny

In article .com,
"Dan" wrote:

Press and hold the OUT button while turning the GPS on.

What is the OUT button? (Is that one of the ZOOM buttons?)

Dan wrote:
I inquired to Garmin Tech support about our problems and got the
following response about clearing the almanac. Probably worth a shot.


Dan,

I spoke with Garmin today and got the same reply today. I followed the
procedure to reset the almanac and it took maybe 20 minutes to
complete. I also discussed a problem I am have having with my
lightspeed thirty 3Gs where I get a squeal through the headset when
attached to the 396 when the 396 is plugged in to the cig. lighter.

The support guy suggested I try a ground loop isolator between the 396
and the headset battery box. He mentioned RadioShack, but theirs does
not natively support the 3.5mm (1/8 inch) jack (RS requires a cable
adaptor). I did find a product at crutchfield.com ( 127SNI135 PAC
SNI-1/3.5 Minijack Ground Loop Isolator) that has female / male 3.5 mm
jacks. They web site has 5 testimonials, 2 from 396 owners, asserting
it solved all problems with using the 396's XM radio in the cockpit. I
ordered one today for about $18.00 + $6 shipping. I'll post a reply
next week with the result, but it looks promising.

-Bernie

GPS units need to have a "quadrifilar" design antenna or they will not
work well.
I had an older Garmin that I connected to an older stock GPS antenna
outside the Cherokee and it still would not work reliably. There is
information on this design antenna on the web. Magellan uses the quad.
http://www.qsl.net/n8imo/qha_4.html

You are either funning us, or you have absolutely no idea what a quadrifilar
antenna is. A two foot high antenna mounted on a 6 foot high mast isn't
going to mount easily on anybody's airplane, let alone a homebuilt.

Your "older Garmin ... connected to an older stock GPS antenna" probably
didn't have an amplifier in the antenna with enough gain to overcome the
loss in the coax you used.

Most GPS external antennas use a modified patch antenna with a 25-30 dB
amplifier mounted to the backside of the patch.

Jim


"darthpup" wrote in message
oups.com...
GPS units need to have a "quadrifilar" design antenna or they will not
work well.
I had an older Garmin that I connected to an older stock GPS antenna
outside the Cherokee and it still would not work reliably. There is
information on this design antenna on the web. Magellan uses the quad.
http://www.qsl.net/n8imo/qha_4.html