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Lowest cost GPS navigator options

uk_figs

Well Known Member
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Looking at the options to add GPS navigation/approaches to my legacy glass panel (D100, SL30, HS34, 327, GDL82, GDL39, 796, Gemini A/P).
Are there any lower cost alternatives to the Garmin 175/375 that should be considered that can fly GPS approaches (arinc 429 to the Gemini A/P)?
I do not want to rip out and replace the entire panel.
Appreciate any (printable :D) suggestions.
Figs
 
I am thinking about pulling the trigger on an IFR upgrade, and to me, it looks hard to beat the GPS 175. I see used GPS400W's on the market for $3500-4000, which is barely less than a 175, and for way less functionality and little to no support from Garmin anymore. It's certainly not cheap, but even the older used units aren't much cheaper, so might as well go with newer and better.

I'm all ears if somebody has a comparable but cheaper solution.

Chris
 
I'm all ears if somebody has a comparable but cheaper solution.

Chris

Apparently the cost of getting a TSO is phenomenal. For a while GRT offered a $750 software package with their HXr and $500 gps which contained every US gps approach, but no TSO. They said up front, ‘vfr only’. I don’t think it sold well.
 
More questions

A few follow up questions:
1. If I installed the 175, can the GDL 82 GPS antenna signal be split to support both units or would I need another GA 35 GPS antenna.
3. If I went with the 375 assume I could reuse the GDL 82 and GTX 327 antennas but would I need another antenna for the ADSB In (the 375 installation guide only shows one xponder antenna)?
Thanks
Figs
 
Go with two GPS antennas

A few follow up questions:
1. If I installed the 175, can the GDL 82 GPS antenna signal be split to support both units or would I need another GA 35 GPS antenna.
3. If I went with the 375 assume I could reuse the GDL 82 and GTX 327 antennas but would I need another antenna for the ADSB In (the 375 installation guide only shows one xponder antenna)?
Thanks
Figs

Figs,

Where the GDL82 and both the 175 and 375 use the same GPS antenna, it is really not good to share that antenna. There are a few GPS antenna splitters on the market, but if you get a weak signal because it goes through a splitter, and you position drops to many times, you will get a letter from the Feds that you are not in compliance and will be told to fix it, and if you don’t do it in 45 days, you will be put on a naughty list. Yes, there is one. It is just easier to mount both antennas.

As for the 375, there is only one transponder antenna connected to the unit, and it uses that antenna for both out and in.

I did install a 375 a year ago in a friends RV6, and it works fine for both in and out using just the one transponder antenna.

If I needed to do this again, and money was not a restriction, get the 375, use the same GA35 antenna, and transponder antenna, and sell the GDL82 and the GTX327.

Note, if you really want to spit the GPS signal, go to eBay and look for GPS Splitters. Many listed. They do work, but are they worth the pain you might get if they don’t?

Good luck.
 
DO NOT split the GPS antenna output.
And I agree with the above, install the 375 and sell the 327/GDL82/GDL39.
 
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If the 375 is like the 430, you should have the ability to feed the signal to the GDL with a single wire. Can't think right now - RS232? or some such port. Look at the install manuals for each.
 
GNX375

If the 375 is like the 430, you should have the ability to feed the signal to the GDL with a single wire. Can't think right now - RS232? or some such port. Look at the install manuals for each.

Larry,

The GNX375 is the GPS175 with a built in transponder, so it has both ADSB OUT and IN. ADSB is displayed on an iPad. You don’t need the GDL for ADSB IN.
 
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Antenna

If you keep the gdl82, you can reuse that ga-35 antenna for the gps-175 and then connect the 175 to the gdl via res-232. You could buy the GPS-175 without the antenna for less than $4K.
 
Question

If you keep the gdl82, you can reuse that ga-35 antenna for the gps-175 and then connect the 175 to the gdl via res-232. You could buy the GPS-175 without the antenna for less than $4K.

Nick,

The install manual says it will only connect to a GDL88, since I know you guys know more than I do, will it also connect to a GDL82?

Thanks for the info.

Brian
 
If you keep the gdl82, you can reuse that ga-35 antenna for the gps-175 and then connect the 175 to the gdl via res-232. You could buy the GPS-175 without the antenna for less than $4K.

Interesting input so the 175 becomes the external GPS/SBAS source over RS232 for the GDL82. The GDL82 installation manual that I have (Rev 3) does not mention the 175 as an external source (section 4.3) but that may be a timing issue as I installed the 82 as soon as it was released a few years ago.

Now I have to look at the various interfaces:
175>>GDL82>>RS232
175>>HS34/D100/CDI>>Arinc 429? (does it need more than this for air data/encoder information from the D100)
175>>Gemini A/P>>Arinc 429
175>>Aera 796>>RS232? (may be a problem as the 2 796 RS232 connections are in use for the SL30 and the GDL39, maybe BT?).
175>>GDL39>>RS232/BT?
175>>SL30>>RS232

Does this look about right? Still more thinking.
Figs
 
And I agree with the above, install the 375 and sell the 327/GDL82/GDL39.

Unless anonymous mode is important to you.

Check with Garmin (or Walt), but I suspect you could use the GPS antenna for the GPS-175, then feed the GDL-82 the GPS signal information over rs-232. You just need to make sure that the internal GPS in the GDL-82 can be disabled.
 
If you keep the gdl82, you can reuse that ga-35 antenna for the gps-175 and then connect the 175 to the gdl via res-232. You could buy the GPS-175 without the antenna for less than $4K.

I do not have the install manual for the 175 but have read on the web that my GDL39 3D is not supported so I would not have traffic and weather on the 175, only on the 760 or Garmin Pilot on the iPad.
 
I installed the GDL-82 with the GA35 antenna first and the setup worked without any issues. Earlier this year, I installed a GPS175 and used the same GA35 antenna. The GPS175 has fed the GPS data through the RS232 link without any issues over the past 40 hrs. In the GDL82 Install Tool, I just needed to change one setting. Anonymous mode was maintained.

I use a GDL39 to feed ADS-B in to my G3X. The GPS 175 screen is so small compared to the 7" GDU. I find the other traffic easier to distinguish on the GDU screen.
 
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