I clicked send to fast, I also had meant to add that Garmin's specs
for the GXM-30 and GXM 30/A XM antennas state that the antenna alone
consumes 4.5 Watts at 4.5 to 5.5 VDC (i.e. about 0.4 amp equivalent at
12 volts). Not insignificant ( a good transponder) anecdotely it
seems that the XM antennas (plus overhead on the GPS unit?) consume
more than this so some real world measurments of the total draw at 12
volts of the GPS and antenna would be great.

Thanks


Darryl

On Mar 12, 1:39 pm, "
wrote:
Eric

WX Worx spec the receiver as 1 amp at 9 volts. Ouch. The Manual for
Anywhere Map XP warns the same XM antenna draws over 1 amp.This seems
to be the most popular (only other portable?) non-Garmin XM Weather
receiver.

The other problem is visibility of the map displays. On my iPAQ 4700
running SeeYou Mobile my 40+ year old eyes can barely see anything at
maximum backlight unless I turn off terrain so the background is
white. I can't think how bad trying to look at XM weather cloud tops
or Nexerad might be. And I've go a very good PDA mount position with
the PDA close to me, angled to minimise sky reflections and using a
cleartouch screen protectors (which improve thigns slightly). I know
peoples contrast tollerance with transflective displays varies a lot
but still I coudl not imagine trying to look at this stuff on my PDA
display.

Again, it would be geat if anybody has power consumption numbers for a
Garmin 396 or 496 with and without the XM weather antenna operating.
Ideally also with internal battery charging and internal barttery
fully charged. I've asked Garmin for this information as well. As far
as I know there is also no way to set the backlight to timeout on the
396 or 496 while it has external power. So these numbers should
ideally be at whatever backlight setting makes the display reasonably
daylight readable.

BTW the WX Worx bluetooth antenna would be really nice, having to run
another cable for the Garmin antenna is a pain.

Darryl

On Mar 10, 10:16 am, Eric Greenwell wrote:

Andy wrote:
I have a Garmin 396. I also had the lite weather, upgraded to full
for Oshkosh last year and have not reverted to Lite. The winds aloft,
cloud cover, and storm cell depictions were very nice to have on the
return from Oshkosh to Phoenix.

I have not used it in the glider mostly because I didn't do much
soaring last year. I think its use in contests is prohibited, but I
think it would be very helpful for non contest XC.

The Garmin XM antenna is a power hog though. You can run the 396 all
day on batteries without it but you need external power if the XM
antenna is connected. I have found no way to turn off the antenna and
leave it connected.

One can also get XM weather using a PDA and Anywhere Weather. It's much
cheaper solution than a 396, and could serve as a backup soaring
computer. Possibly, one could switch between the two programs and get by
with only one PDA in the cockpit. I don't know what draws for power. Can
anyone comment on Anywhere Weather?

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes"http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org