Garmin 430W GPS antenna problem.

[Mooneymite]

Yesterday, about 3 minutes after takeoff, my 430W completely lost lock.  The satellite acquisition page popped up and showed no satellites.  No amount of cycling on/off would get it to work.  I got out my trusty hand-held GPS and....it took a long time to lock on and periodically lost satellites!  I told ATC and continued home in clear skies.

 

Today, I called Garmin and was told that the early version of the WAAS up-grade antenna was "probably the problem".  Apparently Garmin knows all about this.  According to Garmin, in certain failure modes it blocks GPS signals in the immediate vicinity.  Not only do you lose your 430W, but it prevents other GPS from working reliably!

 

Anyone else come across this?

 

Strangely, my 430 acquired and locked on after landing.

[rbridges]

Yesterday, about 3 minutes after takeoff, my 430W completely lost lock.  The satellite acquisition page popped up and showed no satellites.  No amount of cycling on/off would get it to work.  I got out my trusty hand-held GPS and....it took a long time to lock on and periodically lost satellites!  I told ATC and continued home in clear skies.

 

Today, I called Garmin and was told that the early version of the WAAS up-grade antenna was "probably the problem".  Apparently Garmin knows all about this.  According to Garmin, in certain failure modes it blocks GPS signals in the immediate vicinity.  Not only do you lose your 430W, but it prevents other GPS from working reliably!

 

Anyone else come across this?

 

Strangely, my 430 acquired and locked on after landing.

 

so, what is garmin's recommendation?  are they going to help you with a new antenna, or are you having to pay for this on your own?

[Mooneymite]

so, what is garmin's recommendation?  are they going to help you with a new antenna, or are you having to pay for this on your own?

 

Garmin says the antenna is probably bad.  I have a call in to the local Garmin dealer.  I'll let you know.

[ELT]

Yes, I just went thru this.  However my 430W was installed new in late 2012.  The antenna reradiates a signal and takes out ALL GPS equipment on the aircraft.  My instructor and I launched in a 400 overcast for a ICC.  The 430 took out my 496, iPad and iPad mini.  The only approaches and navigation here are GPS.  FUN, NOT.  The avionics shop got my antennae covered under warranty.  This is a know problem

Eddie

[Bob]

Happened on my 480.  Called Garmin and they said that the early antennas were produced by an outside company.  The antenna shorts and causes a field around the fuselage and blocks the signal to everything, I lost may WSI weather and Ipad.  If this happens in flight, turn off the Garmin unit and you regain signal for all the other units.  I asked how long they are covering the replacement since my unit was well out of warranty.  The reply was interesting, " At this point we are covering the cost on these antennas indefinitely."  They sent the new antenna to a Garmin avionics installer and after the swap, the avionics shop sent the old antenna back for testing.  Basically for me, I covered the labor and shipping one way and Garmin provided the part.  Just call Garmin and let them know that you are educated about the problem ask them what is needed to get a replacement.  They handled my antenna fair!

 

When my antenna shorted, it was a high workload flight.  Lost my vacuum just after takeoff (unrelated), that makes the autopilot dead, in VMC (thank God!), then the panel mounted 480 looses signal and so does the Ipad..  Due to high workload, I did not turn off the Garmin, I just flew the plane, asked ATC about satellite issues, got a pilot report from another aircraft and navigates by VOR.  On my test flight to figure out the failure, after the vacuum repair, I thought of turning off the Garmin since my workload was much lower.  It is very strange when loosing your GPS if you use it all the time.  Knew how to navigate, but still strange!

[Mooneymite]

Wow!

 

The more I look into this, the more I find that my experience is widespread!

 

Can you imagine what this would do to ATC in an ADS-B environment!

 

I spoke to the antenna manufacturer....not Garmin and they opined that the problem hasn't been totally resolved.  No one understands everything about what causes this to happen.  Changing out the antenna is their best solution for now.

[Piloto]

I thank you for exposing the problem. My 530W is connected to the old Garmin GPS antenna and never had a problem. In fact vertical accuracy is within +2ft of field elevation.

 

José

[Mooneymite]

I thank you for exposing the problem. My 530W is connected to the old Garmin GPS antenna and never had a problem. In fact vertical accuracy is within +2ft of field elevation.

 

José

 

I installed my 430 in '04, upgraded it to a 430W in '06.....never, ever had the slightest problem until yesterday.

 

Though it "seems" to be working fine today, I don't have the same level of trust in it that I did.

[Marauder]

Let me add another bit of firewood to this fire. I fly behind a new GTN 650 and have twice experienced a LOI message on an approach. My theory is a little different. Both times it happened, I was using the Comm when it dropped out. And both times in was in the 13x bandwidth. I wonder if Comm interference is happening. Electrical interference is a known commodity. I work in a building that is completely filtered for electrical interference from the outside (I would tell you what I do, but I would have to kill you afterwards ). Seriously, with the amount of electrical "noise" in our environment, I'm surprised we are not seeing more of it. Not sent from my underpriced Nexus 7 using Tapatalk

[carusoam]

One of the earliest posts on MooneySpace was a couple of people with Garmin antenna problems with pairs of G5xx and G4xx.

Sounds like a modern version of the same issue.

Unfortunately I don't recall the solution from 4 or 5 years ago...

I had a Narco nav/com radio that would wipe out the GPS signal for my portable unit.

Best regards,

-a-

[MB65E]

Had a 750W spit a message and drop coverage the other day, 650 remained solid. Gained access to the 750 antenna an gave the 90* connector a 1/8-1/4 turn. No issues since. Our 530 was sent in for the WAAS upgrade mid 2012?. Any 530 issues? I think it's the same 430w antenna?

I've had problems with faulty 90* connectors in the past. Brand new outta the box failures on the connectors.

-Matt

[Alan Fox]

Why would Garmin pay for an 8 year old antenna , stuff breaks......It is silly to even think they should..... They are a company that is in business to make money......

[mike_elliott]

It would seem this is the sort of thing AD's should be all about, vs tail huck bolt inspection within the next 10 hours flight.

[N601RX]

Let me add another bit of firewood to this fire. I fly behind a new GTN 650 and have twice experienced a LOI message on an approach. My theory is a little different. Both times it happened, I was using the Comm when it dropped out. And both times in was in the 13x bandwidth. I wonder if Comm interference is happening. Electrical interference is a known commodity. I work in a building that is completely filtered for electrical interference from the outside (I would tell you what I do, but I would have to kill you afterwards ). Seriously, with the amount of electrical "noise" in our environment, I'm surprised we are not seeing more of it. Not sent from my underpriced Nexus 7 using Tapatalk

There is a notch filter available for this. The harmonics of certain com freq fall in the gps band.  I'm not sure if the garmin install manual mentions it or not, but if you look in the KLN94 install manual under the checkout procedure it tells you what frequencies to check for interference on.  You basically put the com on that channel and key it up for 30 seconds while watching the satellite status page that shows the signal strength.  We have a large 4 meter RF Anechoic chamber here at work. Kind of eerie when you go in and shut the door. People have been known to get locked inside occasionally.

[OR75]

maybe a little off topic but i always found it odd that the FAA would be ok with accepting that a GPS/WAAS would be acceptable as a sole mean of navigation for IFR operations.

[Marauder]

There is a notch filter available for this. The harmonics of certain com freq fall in the gps band. I'm not sure if the garmin install manual mentions it or not, but if you look in the KLN94 install manual under the checkout procedure it tells you what frequencies to check for interference on. You basically put the com on that channel and key it up for 30 seconds while watching the satellite status page that shows the signal strength. We have a large 4 meter RF Anechoic chamber here at work. Kind of eerie when you go in and shut the door. People have been known to get locked inside occasionally.

Thanks for posting this. Now I know what to ask for!

Not sent from my underpriced Nexus 7 using Tapatalk

[DrBill]

We have a large 4 meter RF Anechoic chamber here at work. Kind of eerie when you go in and shut the door. People have been known to get locked inside occasionally.

That brings back fond memories.. When I worked for Big Blue, I managed an engineering team responsible for the analog and RF characteriscs and ckts for printers. We spent many hours in our chamber like the one pictured above. I later got my PhD in wireless communication. Good stuff ! Thanks !

BILL

[N601RX]

That brings back fond memories.. When I worked for Big Blue, I managed an engineering team responsible for the analog and RF characteriscs and ckts for printers. We spent many hours in our chamber like the one pictured above. I later got my PhD in wireless communication. Good stuff ! Thanks !

BILL

We do a lot of 450 and 900MHZ design work and basically needed the ability to know that our designs are going to pass certification before going to the FCC for certification.  I think we paid around 500K for the chamber above. The antenna in the picture recently received a  small dent and had to be replaced for 10K.  Worse $$$$ than airplane parts.

[Mooneymite]

It would seem this is the sort of thing AD's should be all about, vs tail huck bolt inspection within the next 10 hours flight.

 

I had the same thought!

 

Think of the guy counting on WAAS sole-source.  He's filed to Rnav fixes and loses all GPS capability....now add on that he's ADS-B.

 

While something like this can happen in any installation, it is remarkable that Garmin and all the techs I've spoken with are very familiar with this antenna wiping out all GPS capability, but no one thinks word should be spread and faulty antennas found/replaced!

[yvesg]

There is a notch filter available for this. The harmonics of certain com freq fall in the gps band.  I'm not sure if the garmin install manual mentions it or not, but if you look in the KLN94 install manual under the checkout procedure it tells you what frequencies to check for interference on.  You basically put the com on that channel and key it up for 30 seconds while watching the satellite status page that shows the signal strength.  We have a large 4 meter RF Anechoic chamber here at work. Kind of eerie when you go in and shut the door. People have been known to get locked inside occasionally.

On my flight to Long Beach two weeks ago, I recall an event where I was asked to contact the next terminal center and the frequency was 133.00. I switched the COM of my 430W to that and when i got there, I had a dead carrier and could ear the controller transmitting (his signal strength was below the dead carrier) behind this (but could not decypher him) with the beat tone associated with two carriers spreaded apart with something below 1000 Hertz... so I thought here is an idiot with a stuck mike on that frequency! i had the clairvoyance to turn off my other COM unit... as soon as i did this, the carrier went away... it was a spurious emission from my second COM unit causing this signal. Having two radios is good but sometimes they might step on each other.

Yves

[Marauder]

On my flight to Long Beach two weeks ago, I recall an event where I was asked to contact the next terminal center and the frequency was 133.00. I switched the COM of my 430W to that and when i got there, I had a dead carrier and could ear the controller transmitting (his signal strength was below the dead carrier) behind this (but could not decypher him) with the beat tone associated with two carriers spreaded apart with something below 1000 Hertz... so I thought here is an idiot with a stuck mike on that frequency! i had the clairvoyance to turn off my other COM unit... as soon as i did this, the carrier went away... it was a spurious emission from my second COM unit causing this signal. Having two radios is good but sometimes they might step on each other.

Yves

 

Speaking of radios. What do you guys think about the transmission capability of Garmin Comms versus other brands? I have flown behind King KX-170Bs, a Michel slide-in replacement and finally a Narco Mark 12D+ before I bought the Garmin GTN. Despite having a belly mounted Comm antenna, I find I have more problems having Centers hear me on my GTN than my top antenna mounted Narco unit. Poor installation? Antenna problem or are Garmin radios more problematic?

[yvesg]

The most problem I had when flying in USA around new year was due to my French accent I think. One controller gave up trying to understand the type of aircraft and entered me in the system as experimental lolll. I got this corrected further along the route.

The Garmin radios have to meet specifications that are fairly stringent. They would not have got their approval if they would be low quality as far as distorsion and so on. I was surprised on the answer of the avionics shop answer to my question: Did you check the SWR of the antenna? They did not.

i would check that way if i were you.

Yves

[yvesg]

For the above: I asked the question after my garmin install, before Christmas.

[N601RX]

Speaking of radios. What do you guys think about the transmission capability of Garmin Comms versus other brands? I have flown behind King KX-170Bs, a Michel slide-in replacement and finally a Narco Mark 12D+ before I bought the Garmin GTN. Despite having a belly mounted Comm antenna, I find I have more problems having Centers hear me on my GTN than my top antenna mounted Narco unit. Poor installation? Antenna problem or are Garmin radios more problematic?

Com radios use am modulation and if over modulated they will cause distortion and harmonic spurs.  Radios as well as many headsets have a mic gain adjustment on it. I personally feel that the King Kx155/196 vintage of radios have better receivers than some of the new stuff.

[OR75]

I fly with a GNS 430 and a KX-155

 

The KX has always felt stronger (if it is difficult to hear what Center is saying, switching to the KX usually helps a little) 

 

In another instance where my plane has been sitting on the tarmac in South Texas with the early afternoon sun beating,  the GNS was inop when I got started but the KX-155 was working. 

 

The only drawback of the KX-155 is the delaminating of the orange lenses and sometimes the digits going but that is a very easy fix.

 

I would not remove the KX (unless all VORs are gone)