"Dan" wrote in message oups.com...
:I found the problem! Those with 396s might be interested in the
: solution.
:
: I setup the 396 w/ external antenna in the car and proceeded to drive
: to the airport. Satellite signal was great for about 15 miles until I
: arrived at an intersection in the city. All of the sudden, signal
: strengths quickly dropped to zero and I got the "signal lost"
: message. A half mile or so later, all was fine. Strange...
:
: Continuing towards the airport, I arrived at another spot where the
: signal dropped to zero. It was in an especially open area, so
: obstructions were not the problem. I quickly pulled over. The signal
: stayed at zero, and I looked around to see what would be causing it.
: Sure enough, about a quarter mile away were two cell towers with a
: clear line of sight to my vehicle. If I moved such that a building was
: between me and the cell towers, signal came back. If I switched to the
: "stick" antenna, signal came back as well.
:
: So, the problem is the external antenna has some kind of reaction when
: in close proximity and line of sight to certain cell towers. Just like
: the kind of situation right after takeoff at CHD, and also in the
: pattern. At high altitudes, it's not an issue, just in the pattern
: near this area. This also explains why sat lock is rock solid in
: cruise and out in the boonies.
:
: I did further testing which confirms my theory. Seems I'll be
: requesting a new external antenna from Garmin, or purchasing a 3rd
: party external antenna. For now, I'll just use the "stick"
: antenna. This was certainly unexpected.
:
: --Dan
:


Probably the magnets in the external antenna are pulling in those cell signals.... ;-)