396 drops WX

petehowell · #1 06-08-2010, 02:37 PM

Hey Guys,

I have a 396 that works great for about 2 hours and then it drops the WX coverage(metars and Nexrad). It comes back the next day, but only for about the same 2 hours. The XM signal is strong and I can get audio, but no wx. The GPS position and mapping have been flawless. Internal battery has been replaced. Rebooting in flight has worked once, but not consistently.

I thought it might be the antenna heating up, but I have covered it from the sun with no luck - any thoughts? I have some long XC trips planned and would love to have it available for the entire trip.

IowaRV9Dreamer · #2 06-08-2010, 10:40 PM

Pete - the XM audio and XM Wx all comes in as digital data from the satellite. The only difference between the two is software decoding. It's hard to think of a hardware problem that would affect one but not the other.

Are all of your XM products gone? Sometimes NEXRAD doesn't work if the receiver cannot accumulate the entire data set (like if you are turning a lot and the antenna cannot "see" the satellite for long enough.

How about some of the simpler products, like "county warnings"? They contain very low amounts of information, and tend to come in easier.

If you can find a friend with a 396/496 with XM , you could try to swap out the antenna. Remember that the antenna is actually the entire XM receiver including the decoder.... so if you swap with a friend your 396 will get the weather products he subscribes too.

Good luck!

petehowell · #3 06-09-2010, 05:39 AM

I have not looked at county warnings, but will. I lose the TAFs, Metars and the radar for sure - but still have a great signal and the audio channels. I'll grab the hangar mates antenna next trip and do a side by side to isolate the issue.

bsacks05 · #4 06-09-2010, 05:49 AM

I had to move around my aprs and xm wx reciever pucks until I found the spot where they play nice together. Seemed to be that if the aprs was too close to the xm, one or the other would not work. Now I have the aprs puck on the seatback bulkhead and the xm wx on the glareshield and all is good.

tc1234c · #5 06-09-2010, 06:24 AM

Pete,

I share the same frustration with WX on Anywhere Map. I flew to Florida over the Memorial weekend. WX worked perfectly on the trip down (with a lot of scattered thunder storms). On the way back one hour into the IFR flight I lost WX. It still showed good signal. When I landed for fuel I was going to call XM. As soon as I booted up the system (to get the 800 number and radio ID) it worked. On my next segment It again worked for 1 1/2 hrs before dropping out.

I remember a year or two ago I had a lot of problem. It turned out that XM had changed data format. After Anywhere updated software it worked perfectly. Maybe it is time to give Garmin a call to find out whether this is the case.

mburch · #6 06-09-2010, 06:40 AM

Rather than software, I would be more inclined to suspect a hardware issue... either a loose/intermittent connection, or a problem with the XM receiver.

good luck,
mcb

Ironflight · #7 06-09-2010, 09:05 AM

Sure sounds like a thermal/hardware issue to me - hard to think how it could be software. I had a "funny" a coupe of weeks ago with the 696 - noticed I had no XM at all, so I pulled out the USB plug from the antenna and put it back in. Fixed the problem instantly. I hadn't moved that plug for months....maybe some corrosion had set in?

Paul

turbo · #8 06-09-2010, 10:23 AM

antenna. i had one go bad on me. i lot of heat in florida. i cover it up now when i am on the ramp. i cover the zaon and 496 too. stay cool. turbo