MGL Avionics User Forum

I use an EFIS with an iBox. in the past years we had a few GPS failures, where GPS data was intermittent with periods of upto 30 minutes without GPS data. In all cases, replacing the antenna solved the problem. I am using the same GPS antenna that is supplied in automotive navigation devices.
Any advice on the reason for frequent failures.
Any advice on high quality antennas that will last longer than 2 years?
What installation requirements for reliability?

Antennas should last "forever". The EFIS supplies 3.3V to power the antenna pre-amp. Most of these antennas are designed to operate from 2.5 to 3.6V.
If you use a passive antenna - make sure you have a DC block (just a capacitor). Some antennas "leak" and this can cause galvanic corrosion due to DC current flowing through junctions of different metals.

Also make sure the antenna cable itself is properly supported and no section is allowed to move with vibration, bumps and turbulence. Nothing damages wiring more than continuous flexing. Some wires can withstand more others less - but no matter what you use - eventually it will fail.

I'm still using the same antenna I first installed in my own aircraft. That's now around 12 years in operation...

Hi Ofergd

Why are your GPS antenna's failing so often?

First off the number one problem as Rainer mentioned, vibration, vibration and vibration and then more vibration again.

Vibration is the number one problem for most avionics, the more vibration you have in your airframe the less trouble free operating hours you will get from your avionics or EFIS system unless you try to protect every part of your system from this vibration. The odd person does say they don't understand why, well think of this vibration like a very small earth quake running through your airframe as you fly.

It's not enough to causes things to break straight away, but over a time it causes cracks in solder, larger semi conductors to crack off PCB or automotive type wires to crack and break inside it's insulation from this never ending movement from vibration.

There is an old saying, Apples aren't Apples and then even within apples, there are differences.

Years ago I had a C150 starter motor that needed rewinding. My lame said take it to these guys, make sure you tell them it's for an aircraft. I asked what's the different for an aircraft, they triple dip them into the vanish so the winding has more support and can handle the engine vibration for longer.

So, as a starting point, I would suggest that you google MGL and find the MGL dealer in your country and order a MGL GPS antenna. You may feel a MGL GPS antenna will not have any better performance and it looks no different.

But at least you know you have removed the potential problem of having a mismatched passive or active antenna with your MGL EFIS and maybe the MGL manufacturer has already worked out for you what's the best GPS antenna to work with their EFIS and to give you the best service life for any given situation.

Maybe you might like to read other posts on the forum as well about GPS issues, if you have not already done so.

Cheers
JimJab