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  #1  
Old 05-12-2023, 04:38 AM
amekler amekler is offline
 
Join Date: Aug 2009
Location: Gilford,NH
Posts: 212
Default GPS antenna issue?

I have a 2009 RV-10 with the Garmin GPS antenna mounted on the glare shield. 3 years ago I upgraded from a Garmin 430W to an Avidyne IFD440.
I have had loss of satellite reception 3 times this year. Sent my logs to avidyne and they think is an antenna/cable issue. They recommend the antenna be moved externally and I check cable.
any advice where to mount it and how to check the antenna and cable?
N668G
RV-10
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  #2  
Old 05-12-2023, 05:48 AM
D-Dubya D-Dubya is offline
 
Join Date: May 2009
Location: Beaumont, Texas
Posts: 344
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A basic tenet of troubleshooting is determining when the problem started. If the plane has been flying for over ten years and the location of the antenna hasn't caused any issues, it's likely not that. Well, unless something has changed that would affect that (e.g. painting, covering, etc.).

Can you hit up one of your flying buddies to borrow an identical antenna for a temporary swap? Manufacturers don't exactly give those things away, so I wouldn't just buy a new one without knowing it's really a problem. How about the connectors...any corrosion on those? Is the cable itself in good shape? If in doubt, installing a new cable is a lot cheaper than an antenna.

Lastly, Garmin has a test where you measure the voltage at the antenna end of the cable--if it doesn't have 5 volts, then there's something wrong before the antenna. One of the Garmin experts may want to weigh in on that, as I'm going back a few years from memory. And that can be an iffy thing.
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RV-7 N413WD
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  #3  
Old 05-12-2023, 07:31 AM
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Carl Froehlich Carl Froehlich is online now
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 4,340
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Quote:
Originally Posted by amekler View Post
SNIP
I have had loss of satellite reception 3 times this year. Sent my logs to avidyne and they think is an antenna/cable issue. They recommend the antenna be moved externally and I check cable.
Try watching the satellite reception page. You may find the number of satellites received and signal strength will be affected by normal actions. I had a similar problem with a GTN-650 - when transmitting on the 650 all satellites would go away. Nothing else affected reception.

I donít know about Avidyne antenna guildlines but perhaps this is a similar issue. I suspect you will be moving the GPS puck someplace else. The aft deck behind the fiberglass cabin top is the most common.

Carl
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  #4  
Old 05-12-2023, 07:37 AM
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Jpm757 Jpm757 is offline
 
Join Date: May 2013
Location: Sherman, CT
Posts: 1,174
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I have had no problems with a Garmin and Dynon GPS antennas mounted together under cowling. Search numerous posts regarding GPS antenna mounting locations.
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RV6 #20477 completed 1991 sold.
RV7 #72018 N767T first flight 11/21/2017
(KOXC)Oxford, CT, (0NY0)North Creek, NY.
1941 J3 Cub skis, floats.
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  #5  
Old 05-12-2023, 08:40 AM
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sahrens sahrens is online now
 
Join Date: Jan 2007
Location: Battle Ground WA
Posts: 732
Default Check installation

When the Avidyne was installed did you use the Garmin tray? I would remove the Avidyne unit and check all the pins and especially the antenna connection. Make sure the coax is firmly connected to the back of the tray. Then carefully reseat the unit making sure it is fully in the tray.

You have described the problem as intermittent. I suspect a lose connection.
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  #6  
Old 05-13-2023, 04:57 PM
amekler amekler is offline
 
Join Date: Aug 2009
Location: Gilford,NH
Posts: 212
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thanks
I've been monitoring the sat page and haven't noticed anything. The antenna has been in that position for 14 years and this issue just started.I've had the ifd440 about 4 years now.
I'll check the cable first before replacing/relocating the antenna
Alan
N668G
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