Issue with Voyager EFIS GPS.

[JimJab]

Well here is a further up date on my GPS issue for those that are following.

I got impatient with the EFIS sitting on the bench waiting for the ribbon cables to arrive. So I left the camera ribbon cable swapped over and re-installed the Voyager EFIS into the plane. Just as a side note, I have two Voyagers and as far as I know from the aircraft log, the other Voyager has never had a hint of trouble.

I did said in my last post I was quietly confident I had fixed this GPS issue, well I should have been quietly wrong, I took the plane for an hour flight and the GPS work flawlessly, as I was heading back into the circuit area I was thinking yep, you beauty problem solved. Then within a second of that thought I heard "GPS not available" and in another fleeting moment, "GPS Available" and it did this once more before I landed.

As sparxfly said earlier in this post, I should swap some stuff around, so I swapped the antennas between my Voyagers. But the problem remained with the same Voyager, but what did happen after changing the antennas over, the fault with the "GPS not available" and "GPS Available" was now happening 10 times more often in flight.

So the next step when I get the new ribbon cables and I pull the panel and EFIS, I will remove the USB and GPS board from the EFIS and have a good look around that board and the antenna socket for any physical cracking or dry joints.

Hey, if anyone has had this problem before and solved it, I am more than happy to take your advice.

Happy New Year to All,

JimJab

[a.baudry]

Hello JimJab,
I had exactly the same problem on my Voyager G2 during about 2 years. I solved it definitively 8 years ago by changing the GPS board. The new one was fitted with a new GPS module U BLOX 5 (or 6, not sure of the figure) much stronger against electromagnetic disturbances than the original U BLOX LEA 4A.
I purchased the new GPS board at MGL. Before the replacement, each flight was polluted by ‘GPS not available’ messages; since the replacement I never had the trouble anymore… I flew more than 600 hours without any problem.
Regards
Alain

[adamoconnor]

What a saga, Jim!

I'm posting to follow this thread, as I'm interested to see what your investigation will bring to light.

Adam

[JimJab]

What a saga, Jim!

I'm posting to follow this thread, as I'm interested to see what your investigation will bring to light.

Adam

Hi Adam, thanks for your interest, a saga for some and a challenge for others, you could say.

A saga it can be, as I can't make the EFIS fault in the plane on the ground, running the engine at all rpm's with all other avionics and lighting as I do in flight. I even tried getting the instrument panel hot by baking the plane in the hot summer sun, but the EFIS still worked flawlessly on the ground, as it did on the work bench.

My extra GPS antenna cable is coil as it should be so I have ruled that out. But maybe my EFIS has just given up a little hint towards the problem, after I swapped over the GPS antennas between my Voyagers, the frequency of the fault suddenly increased ten fold in the air.

Adam, thanks for your interest, as it makes forum posting worth the effort. It was the past MGL forum and those members who gave up their time to post, that gave me so much insight and information into using and programming my Voyager EFIS's.

It's sad that the old Cherry Forum can't be pulled from the ashes with all that information it held?


Cheers to All
JimJab

[adamoconnor]

A saga it can be, as I can't make the EFIS fault in the plane on the ground, running the engine at all rpm's with all other avionics and lighting as I do in flight. I even tried getting the instrument panel hot by baking the plane in the hot summer sun, but the EFIS still worked flawlessly on the ground, as it did on the work bench.

My extra GPS antenna cable is coil as it should be so I have ruled that out. But maybe my EFIS has just given up a little hint towards the problem, after I swapped over the GPS antennas between my Voyagers, the frequency of the fault suddenly increased ten fold in the air.

Have you added the ground plane yet? I'm wondering if there's any static being generated by the friction of the aircraft through the air that is causing the fault? The ground plane will have to have continuity to the antenna itself and to airframe ground - otherwise all it is doing is acting as an extension to the antenna itself and really messing with things! Another point of note is perhaps there used to be a ground plane but a wire had broken?

I'm not sure of this to be true for this antenna, but in most antennas you can take the screw of the antenna connector and check continuity to ground. It should be 2 ohms or less for acceptable performance. The center conductor may also show continuity to ground via the electronics inside the antenna. That's where the topic of impedance vs resistance comes in that I'm not nearly qualified enough to fully understand much less try to explain

Adam

[bradwalton]

I've also been following this thread because I have the same issue with my G2 Odyssey. I've improved contact between my gps antenna and the metal glare shield. This seems to have helped, but still getting occasional "gps not available". Reboot and it comes back on. Would a more powerful active antenna help?

[JimJab]

I've also been following this thread because I have the same issue with my G2 Odyssey. I've improved contact between my gps antenna and the metal glare shield. This seems to have helped, but still getting occasional "gps not available". Reboot and it comes back on. Would a more powerful active antenna help?

Hi Adam and All,

I am still following up a few ideas about this GPS issue.

My GPS antenna's don't seem to have ground planes and each Voyager GPS antenna is velcro to the top of my instrument panel which is fiberglass (Jabiru ). I realize this may not be the best idea and should be looked into further and make up a couple of ground planes.

I was told by the builder and with my 40 hours flying with the plane, both EFIS GPS's have been rock solid with 3D fixes most of the time with this antenna setup. Could this be because Australia has favorable terrain in my home area (no high mountains) and I have a totally fiberglass plane?

This GPS problem started right on the first flight where I changed my tacho pick-up to the Hall Affect Sensor. So when I get the chance, I am going to change the tacho pick-up back to the ignition coil to see if I get any changes in this GPS problem.

Cheers
JimJab

[JimJab]

Firstly, thanks Alain for you post and I did miss this until tonight, but thankyou for your experience with the GPS/USB board. I am thinking you could be on the money.

Alain, can I ask what actually made you think it was the GPS/USB Board?

I did try swapping the tacho back to the ignition coil but the GPS continued to play up, so it seems like a coincidence that my GPS started playing up at the same time I installed the Hall Effect sensor.

But another step forward, when I was taxing back in from this flight yesterday, with little engine rev's, the GPS started to play up and this was the first time it has done this on the ground.

So I am going to pull the panel again, swap my Voyagers over and whilst I am doing that, I will have a good look at the GPS/USB Board for any physical issues. I am lucky my panel is pretty easy to pull out and take home.

Cheers All

JimJab

[a.baudry]

Alain, can I ask what actually made you think it was the GPS/USB Board?

I spent two years checking everything on my aircraft, changing antenna, wirings etc… until the day Rainier posted the information about the new GPS board less sensitive to the electromagnetic disturbances. I immediately decided to test the new board, and it was done a few weeks later…
I explained all this with lots of posts in the previous forum that Mr Adam O’Connor (Michigan Avionics) has taken over for his own, with thousands of inestimable technical posts from Rainier not anymore accessible for us, users…:
https://www.mglavionics.co.za/phpBB3/vi ... p?f=1&t=16
A real shame
Alain

[odens_14]

I explained all this with lots of posts in the previous forum that Mr Adam O’Connor (Michigan Avionics) has taken over for his own, with thousands of inestimable technical posts from Rainier not anymore accessible for us, users…

I think you're having a misunderstanding and mixing up resources, the knowledge base Michigan Avionics took over was the articles hosted on Matt's website (previous USA distributor/support in California). Yes some of the articles were made from posts on the forum but the articles are still available in Michigan Avionics website support section, for free. I don't think they're keeping anything from the users.

On the other hand, the old forum that is currently lost was due to a server crash. the old forum was run by a user, his old computer died, and Rainer created this forum to fill that void. more info here: https://www.mglavionics.co.za/phpBB3/vi ... hp?f=1&t=3

The pertinent quote on restoring the old forum information, direct from Rainer in that thread (bold emphasis mine):

Believe me, we are trying.
Bill Cherry ran the old forum for what feels like close to 20 years ? It's actually amazing it ran this long on an old PC and using by now ancient software.
Bill is trying to resurrect the server - hopefully for long enough so we can try and extract all the valuable information and post it in some form or another.

I haven't heard if there has been any luck repairing and retrieving any information, but it's certainly not Michigan Avionics hiding it from users like your post would imply and I wanted to make sure no one else got that mistaken impression.