Garmin GpsMap 396 - Flight Test #4

I've got a known good (4 years of field-testing it at every antenna seminar
I've given, roughly twenty of them) external GPS active antenna I'd be more
than willing to loan you to see if it clears up your problem.

The only problem you may have using it for a temporary test is that it
required a 7/8" hole cut into a metal ground plane to perform properly (see
http://www.rst-engr.com/rst/catalog/gps_antenna.html for a picture of what
it looks like). Since you probably don't want to cut a hole in your pretty
airplane for a temporary test, how you fabricate and test the ground plane
is an exercise for the student to do. I have used it with an old CD for a
ground plane and it worked well. You can cut the plastic of the CD with a
hot knife or a skilsaw.

If you want to play with it for a few weeks, just send me a SASE that will
hold something about the size of a baseball and normal copy-paper 18 page
manual. It has a BNC(M) connector attached at the GPS end.

Jim



"Mike Spera" wrote in message
ink.net...
Yesterday we planned on a proposed flight 50 miles away for dinner with a
light GA airplane newbie on board

I am definitely keeping this thing!

Thanks,
Mike

Mike - Thanks for all the interesting PIREPs on the 396. I'm not
considering buying but find the feature descriptions and your
trial/tribulation experience interesting to read.

What are your ongoing costs and what features does that provide?

Thanks.


--
Jack Allison
PP-ASEL-Instrument Airplane
Arrow N2104T

"To become a Jedi knight, you must master a single force. To become
a private pilot you must strive to master four of them"
- Rod Machado

(Remove the obvious from address to reply via e-mail)

In article om,
"Jay Honeck" wrote:
However, size really DOES matter in GPS. The ability to view your
entire route, clearly, without losing too much detail, only comes with
screen size -- and both the AvMap and the Airmap beat the Garmin hand's
down in this department.

The Garmin's screen resolution (480x320) is much better than the
Lowrance AirMap 2000c (320x240), so your ability to view the entire
route has nothing to do with screen size. If you zoom out on the
Garmin, you can view your entire route, but I still think that the
horizontal orientation of the Garmin screen is suboptimal for navigation.

That being said, having the weather is invaluable as a safety and
planning tool. The Garmin screen does make the "big picture" a little
more challenging, but it's certainly better than having no information
at all. Right now, the 396 is as good as it gets for portable in-flight
weather combined with navigation information.



JKG

In article ,
".Blueskies." wrote:
IMHO, the 396 is over priced. Sure, the nexrad radar stuff is good to know,
but it is not a real picture of the storms.
It is a representation of the echoes from the doppler radar station. The
doppler is limited in that if a heavy down pour
is happening, it can not see through that down pour very well and other
stations need to help out with interpolating the
data. I do like the METAR information, but like the radar, you can get
updated from FSS or ATC real time also, but it
does take talking on the radio ;-)

You are not correct about the weather information and, IMO, not correct
about the price when compared to similar products on the market. I
agree, the previous $2695 price tag was a bit expensive, but the new,
lower price is more reasonable.

The NEXRAD information is pretty much as good as it gets. Ground radar
stations are not subject to the same attenuation problems suffered by
airborne weather radar, and as a result, generate a much better overall
picture of current and developing conditions. Composite imagery is used
from multiple radar sites and multiple antenna tilts. Combine the
NEXRAD picture with other data such as Echo Tops, and you have a pretty
accurate picture of developing conditions.



JKG

Jim,

Thanks for the offer, but I believe it is working acceptably now. The
new swap unit did a much better job of receiving sats in all directions.
Upgrading the software to version 3.2 showed an additional improvement.
Transmitting now degrades the reception on one or two sats which is O.K.
WAAS locks and never unlocks. Before, transmitting would bring all sats
to zero in about 7 seconds. Also, it does not lose sats heading
Southeast like the original unit did. They all stay strong.

I may rebuild the almanac for kicks and see if that does anything
positive. Like I said, it now works well enough for me to rely on it.

Again, thanks for the offer.

Mike

RST Engineering wrote:
I've got a known good (4 years of field-testing it at every antenna seminar
I've given, roughly twenty of them) external GPS active antenna I'd be more
than willing to loan you to see if it clears up your problem.

The only problem you may have using it for a temporary test is that it
required a 7/8" hole cut into a metal ground plane to perform properly (see
http://www.rst-engr.com/rst/catalog/gps_antenna.html for a picture of what
it looks like). Since you probably don't want to cut a hole in your pretty
airplane for a temporary test, how you fabricate and test the ground plane
is an exercise for the student to do. I have used it with an old CD for a
ground plane and it worked well. You can cut the plastic of the CD with a
hot knife or a skilsaw.

If you want to play with it for a few weeks, just send me a SASE that will
hold something about the size of a baseball and normal copy-paper 18 page
manual. It has a BNC(M) connector attached at the GPS end.

Jim



"Mike Spera" wrote in message
ink.net...

Yesterday we planned on a proposed flight 50 miles away for dinner with a
light GA airplane newbie on board


I am definitely keeping this thing!

Thanks,
Mike

Jack Allison wrote:

Mike - Thanks for all the interesting PIREPs on the 396. I'm not
considering buying but find the feature descriptions and your
trial/tribulation experience interesting to read.

What are your ongoing costs and what features does that provide?

Thanks.


I purchased the "Aviator LT" package. It is $29.99 per month with a $75
one time activation fee.

It includes METARS, TAFs, TFRs, Nexrad Radar, City Forecasts, precip
type (at surface) and county warnings. There are also some marine
components.

The full subscription ($49.99/mo.) gives satellite mosaic, lightning
strikes, severe storm location and track, surface analysis, winds aloft,
and a bunch of other services.

You can add XM Radio for $6.99/mo. + a one time $14.99 activation fee. I
already hook in my iPod to my intercom so I am not interested in the
radio portion.

Go to www.xmweather.com for the detailed listing.
Thanks,
Mike

In article . net,
Mike Spera wrote:
You can add XM Radio for $6.99/mo. + a one time $14.99 activation fee. I
already hook in my iPod to my intercom so I am not interested in the
radio portion.


BTW, when I called XM to activate the audio content, I was told that
there was no activation fee because the 396 uses the same radio ID for
both datalink and audio--in other words, you aren't activating another
radio, you're simply starting the audio subscription to a radio that's
already activated.



JKG

"Jonathan Goodish" wrote in message
...
In article ,
".Blueskies." wrote:
IMHO, the 396 is over priced. Sure, the nexrad radar stuff is good to know,
but it is not a real picture of the storms.
It is a representation of the echoes from the doppler radar station. The
doppler is limited in that if a heavy down pour
is happening, it can not see through that down pour very well and other
stations need to help out with interpolating the
data. I do like the METAR information, but like the radar, you can get
updated from FSS or ATC real time also, but it
does take talking on the radio ;-)

You are not correct about the weather information and, IMO, not correct
about the price when compared to similar products on the market. I
agree, the previous $2695 price tag was a bit expensive, but the new,
lower price is more reasonable.

The NEXRAD information is pretty much as good as it gets. Ground radar
stations are not subject to the same attenuation problems suffered by
airborne weather radar, and as a result, generate a much better overall
picture of current and developing conditions. Composite imagery is used
from multiple radar sites and multiple antenna tilts. Combine the
NEXRAD picture with other data such as Echo Tops, and you have a pretty
accurate picture of developing conditions.



JKG

The NEXRAD is only as good as the interpretation, like you said. Ground based is subject to the attenuation issues just
like airborne (granted they do have more power so they can see further), and the NEXRAD is not real time as some seem to
think. Like you said, all the data needs to be taken together to get some sense of the conditions, particularly
lightening strikes. Does the 396 display the lightening also?

In article ,
".Blueskies." wrote:

The NEXRAD is only as good as the interpretation, like you said. Ground based
is subject to the attenuation issues just
like airborne (granted they do have more power so they can see further), and
the NEXRAD is not real time as some seem to
think. Like you said, all the data needs to be taken together to get some
sense of the conditions, particularly
lightening strikes. Does the 396 display the lightening also?


Ground-based NEXRAD is NOT subject to the same attenuation issues as
airborne weather radar. Ground-based radar is much more powerful and
uses a much larger antenna, but the real advantage is with the composite
imagery and other radar-derived products, such as Echo Tops. There is
more information about developing conditions in those two products
(NEXRAD and Echo Tops) than you could ever derive from even the best
airborne radar. The big disadvantage to the ground-based products is
that there is a delay between collection, processing, and delivery.
However, this delay is really irrelevant to strategic planning.

The 396 displays lightning, but it's no match for a sferics device
(Stormscope or StrikeFinder). The ground-based lightning detection
network (operated by Vaisala) is not nearly as broad nor as capable as
the ground-based radar network.



JKG

In article ,
Jonathan Goodish wrote:
Ground-based NEXRAD is NOT subject to the same attenuation issues as
airborne weather radar. Ground-based radar is much more powerful and


I should clarify this comment by stating that I realize that all radar
is subject to attenuation, but the results from the terrestrial radar
network do not suffer from the same attenuation-related issues as
airborne weather radar.


JKG