Smelly Mo Posted March 9, 2003 Share Posted March 9, 2003 Took my Legend on a flightseeing trip around Seattle the other day. Plane was small: 7-passenger deHavilland Beaver. Thought there'd be no problem getting good signal in there. Wrong. Zero. Not even a blip. Granted, I did not have line of sight (sat behind the pilot under a high wing) but shoot...I get accuracy down to 10 feet in my house and in my truck with no LOS. I expected no signal in an airliner, but I'm quite disappointed with the thing's performance in the small plane. Any thoughts? Quote Link to comment
+apersson850 Posted March 9, 2003 Share Posted March 9, 2003 According to my previous experience, it never works in planes where you are located under the wing. It simply blocks too much of the view for the unit. But if you have a clear view to one side, it will usually work, except when turning abruptly. In such a case it may loose its bearing for a while, since it hasn't had any chance to lock up to those sats on the other side of the aircraft in advance of the turn. Anders Quote Link to comment
peter Posted March 10, 2003 Share Posted March 10, 2003 Yes, I'm not surprised you didn't get any signal while under the wing. Your house isn't made of aluminum or other metal and is therefore somewhat transparent to the GPS signals (generally materials that are either metallic or have a high water content will block the GPS frequency band) and your truck would have large window areas to allow the signals to enter. OTOH, I've never had a problem getting a decent lock while in an airliner as long as I have a window seat. There the wing is below so the unit can see almost half the sky through the window and receive plenty of satellite signals for a 3D lock. Quote Link to comment
+Jamie Z Posted March 10, 2003 Share Posted March 10, 2003 On other thing I've heard tossed around in the forums is that the front windows on planes are coated with or have a sandwich of some sort of metallic material. Other pilots have mentioned getting no signal at all from in the cockpit, but adequate reception from the passenger compartment. On that note, I've seen this type of glass used. The new public library near my house has enormous front windows... floor to ceiling, but I can't even get one satellite from inside. (Wonder why I was checking?) Jamie Quote Link to comment
jfitzpat Posted March 10, 2003 Share Posted March 10, 2003 FWIW, Small planes usually use plexiglass windows. I've never had trouble with a Vista tucked to the side of the dash on a high wing general aviation plane. Under wing is always very bad. The wing not only is metal, it usually has fuel cells and other obstructions in it. Also, there is usually a pair of VHF ant. right over the cabin, which can generate a surprising about of RF interference. GPS ant. are often mounted right in between them, with a little shielded ring. -jjf Quote Link to comment
+DBleess Posted March 10, 2003 Share Posted March 10, 2003 I use my Garmin GPS 48 as a backup/reference GPS when flying. I use the GA26C remote antenna and the suction cup mount to stick it in place on one side of the sloped rear window. Plexiglass, and a clear view of the sky above for the antenna. Besides the wing structure, I'd say probably a fuel tank and its contents, were probably your biggest obstructions for reception. SA / PP-ASEL-I Quote Link to comment
The Foster Clan Posted March 10, 2003 Share Posted March 10, 2003 I have a couple of programs we use at work on our laptops with remote antenna's and have been able to get great reception while in commercial airliners. I just put it against the glass and lean on it with my shoulder to hold it in place (and hide it from the crew, they seem to freak out for some reason). I'd have to agree with every else's opinion about the wing being above the unit. It's blocking too much of the signal. Jon. Quote Link to comment
Crutch Posted March 11, 2003 Share Posted March 11, 2003 just for info purposes...I use a Garmin Pilot III on yoke mount in Cessna 177 "Cardinal" with stock antenna, and it catches signal great. Also, I put my Plus III on same mount, and get same results. I used to use an external antenna, but now just pop the yoke mount in place and use the standard antenna, and I have 100% faith in the results to back up my panel mount aviation GPS. Jay™ Quote Link to comment
+drat19 Posted March 11, 2003 Share Posted March 11, 2003 I too have had good luck on commercial flights with my GA26 external antenna. I used to use it extensively, and yes, the flight attendants would freak out because it's not in the "approved list" in the magazine, but an experienced flight attendant with a husband who's a geek and knows GPS told me that GPS's ARE in the flight attendant "red book" (that's their internal ops manual). Having said that, I haven't even considered using it on planes since 9/11...I don't even want anyone to THINK about getting nervous about technology they don't understand. And it was interesting/coincidental to me that Crutch (above post) became a registered user on this board on 9/11/01...pretty freaky. -Dave R. in Biloxi, MS Quote Link to comment
jfitzpat Posted March 11, 2003 Share Posted March 11, 2003 Crutch, I'm actually a little surprised. I've had pretty good luck getting reception in low wings, like a Beech Travelair or Bonanza, but I've always had to either tuck by the window or use a remote antenna with various handhelds in highwings. Haven't tried it in a Cardinal, but in quite a few (172RG, 182RG, Skyhawk, Skylane, Stationair, Centurion). Like you, I use it for backup, but I like to get traces to view in MapSource (or fly in Flight Simulator). -jjf Quote Link to comment
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