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Garmin GNS 430 WAAS Upgrade Questions

Ron Lee

Well Known Member
Some useful info in a previous post by MFST-1.

From Garmin I learned the following (hopefully all is correct)

1) Turnaround time is one week

2) Terrain/obstacle functionality is included in the $1500 price. Price may increase some time next year (TBD).

3) Primary nav software may be out 3rd quarter of 2007

4) New antenna and coax (TBD) are included

5) Retains the current mounting tray

6) May require autopilot wiring change/addition

From Jeppesen the database renewals use the same JSUM software and Skybound adapter. Annual cost increases from $375 to $410

My question from anyone who has made the upgrade is it really a remove and replace situation? Will it still drive my Trio wing leveler autopilot with no wiring changes? Is the possible autopilot wiring change if you have altitude autopilot? Any other issues that may affect a decision to upgrade?

Ron Lee
 
More Garmin info

Good point on the new software (JSUM). Found that out by spending 20 minutes on hold with Jepp. This software (like Skybound) is not compatible with Microsoft Windows Vista (yet).

The Jepp people tell me that the 16MB cards take 45 minutes to program.

I slapped my GNS-430 back into the rack and turned it on. All the settings are set back to the default (like 8.33kHz radio spacing and serial port settings). Once I set them to the proper settings the thing has worked flawlessly.

The bootup process seems a little slower (I think).

I have it connected to a GI-106A CDI and a TruTrak Digiflight IIVSG.

The only oddity I have found so far is that when I zoom way way on the moving map, the little airplane does not fly along the pink line when I am on the autopilot. This seems to be a display oddity since the A/P is flying the course that the GNS-430 is outputting.

One feature I like is that on RNAV/GPS approaches, the GNS-430 will give you turn directions like this "Left Turn to 349 in 5 seconds". This is very nice but you still have to watch the CDI. When I flew one the other day, I just started the turn to the heading it told me and managed to turn way inside of the proper path (due to a cross wind).

Bruce
N297NW
RV-8 (425 hrs)
 
Installation notes

As an avionics tech at Aerotronics I have done a dozen WAAS upgrades for my expermental customers. Here are a few things I found important and you want to keep in mind when updating your 430 or 530.

1. When you get your new unit back like the gentlemen said before it is configured back to the factory settings. You will want to go into the programming pages before you send the unit back and copy down all of your original settings. You will need to reprogram these setting back into your new unit.

2. You will have to recalibrate the OBS if you are connected to a resolver indicator, like a Garmin GI-106, MD-200-306 or similar CDI or HSI.

3. There is now a new programming page that requires you to input the distance above ground for the GPS antenna.

4. Yes it comes back with a new antenna, but not coax. Your avionics shop may provide it, but Garmin does not. The new antenna now requires a TNC fitting opposed to the BNC on the original antenna. Now here is something most do not know. Garmin requires the new coax to be RG-400 and there is a specific length. It can't be less that 13ft long or greater than 35ft. At our shop if we are doing an update on a certified plane there is no question, we must follow these requirements.

5. Most installations are a direct replacement and no wiring changes are required, however this is not true for installations to a Sandel EHSI. This requires extensive rewiring depending on how the original installation was performed. There may be others that require rewiring but I haven't run into any yet.

6. I have only done installations on systems that have had Tru Trak autopilots. You have to "Enable VNAV" on the 429 config page and be sure your autopilot is running at least 2.22 software on the DigiFlight models.

I hope this helps some of you.

Jason Smith
Aerotronics Inc.
 
Jason said:
4. Yes it comes back with a new antenna, but not coax. Your avionics shop may provide it, but Garmin does not. The new antenna now requires a TNC fitting opposed to the BNC on the original antenna. Now here is something most do not know. Garmin requires the new coax to be RG-400 and there is a specific length. It can't be less that 13ft long or greater than 35ft. At our shop if we are doing an update on a certified plane there is no question, we must follow these requirements.
Jason, first off, thank you very much for your post. And a couple of
questions if you don't mind.

I'm already using RG400 but it's length is only 3 feet or so. Will this cause
problems or should I coil up an additional 10 feet of RG400 under the panel?

Jason said:
6. I have only done installations on systems that have had Tru Trak autopilots. You have to "Enable VNAV" on the 429 config page and be sure your autopilot is running at least 2.22 software on the DigiFlight models.
I'm sure you meant 430 and not 429?
 
I will answer a little for Jason

He meant 429 as in ARINC 429 which is the protocol used (in addition to serial) to send data between the Garmin 430 and the TruTrak.

I can tell you from real world experience that a shorter length of RG-400 works just fine between the antenna and the unit (though I will have to check on what the book requirement is).

BTW, that TNC adapter is harder than heck to find locally (as in not at Radio Shack) so make sure you have one from your installer or order one from a place like Digikey.

bruce
N297NW
RV-8
 
MSFT-1 said:
He meant 429 as in ARINC 429 which is the protocol used (in addition to serial) to send data between the Garmin 430 and the TruTrak.
Of course. Brain was not engaged fully.
 
more info

walter said:
I'm already using RG400 but it's length is only 3 feet or so. Will this cause
problems or should I coil up an additional 10 feet of RG400 under the panel?

I'm sure you meant 430 and not 429?

I am suggesting for my customers to coil up the excess. Garmin had good reason to require this and who am I to say it would be OK not to. Im not saying the GPS will not work only it must not work up to their standards.

Another item I forgot to mention earlier is a setp in the install book about testing the GPS signal while transmitting on various comm frequencies. In the install book they list about a dozen different freq's on the 25mhz spacing and another half dozen on the 8mhz comm spacing. You are to monitor the GPS strenght while transmitting on each of these frequencies for 35 seconds. If there are two comm radios in the plane you must repeat the steps while transmitting on the other comm as well. They want to ensure RF from either of the comms will not affect the GPS signal. If it does then you look at relocating the GPS antenn.

Jason Smith
Aerotronics Inc.
 
Jason is right...shorter lengths "may" work and some have done it, but you won't be guaranteed a strong reliable signal that is within the spec that the box wants to see. If Son Hoang is on this board he can tell you about a recent headache we had in his RV with a new 430. He installed it, hooked it up and it didn't work - more specifically it couldn't find itself at all. Lots of troubleshooting and we finally started suspecting something with the antenna or cable, so I told him to just hook up a completely separate coax cable about 15' long and put the antenna on a bench outside of his shop. Poof! The unit found itself within minutes.

More research showed that his originally antenna length was about 3' long. He replaced the coax with a longer cable and that problem went away.

So, the moral of the story is that I've seen more than once in RV's that extremely short cables often don't work at all. Sometimes they do, but you're asking for problems down the road or perhaps a degraded or corrupted signal. If you have extra cable and need to coil it up that's what you do, but try to do it at the antenna end instead of the radio end if possible.

Cheers,
Stein.

P.S., nice to see Jason on this board. I've been known to call him for advice more than once!
 
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