GPA 019 vs. GPA 017 on gps 7000 unit



Just up graded to a GP 7000 chart plotter w/ C-Map NT Max on a SD card from a GP 1850D that I had changed from classic charts to C-Map NT on the FP card. The antenna on the GP1850D was a GPA 019 and runs thru the hard top tubing and overhead electronics box so its a pain to remove it, the 7000 came with a GPA 017 antenna I looked at the price difference between the two and the GPA 019 is a lot more expensive. The GP 1850D uses either the GPA017, GPA018 or GPA019 antenna, the GP 7000 manual only shows the GPA 017 antenna for that model. Will I get better results keeping the GPA 019 that's installed on the hardtop with out having to rewire half the boat also.
The GPA019 has an extra DGPS "H-Field" antenna built into it (for use by DGPS type units). If you wish to use the existing antenna (GPA019) with your GP7000, you can. You will still get the same quality WAAS locking that you get from the GPA017. It will save running all the new wire. :wink7
Happy Holidays!
What does the differential DGPS do when hooked up to the 1850D that the GP 7000 doesn't do using the GPA017 antenna,
both get WAAS. Also if selling the 1850D with the GPA017 antenna will it work the same? the manual say's its one of the
antenna's that can be used, or is it better bite the bullet & to take down the GPA019 and install the GPA017 for use on the GP7000? still not understanding about the differential. Any help needed to sell the GP1850d with the right antenna, I would be thankful
The GP1850D doesn't conduct WAAS. Any 1850 unit that conducts WAAS will have a "W" in the part number. (ie. GP1850WDF) WAAS (wide area augmentation system) is conducted via a WAAS satellite. DGPS is conducted via ground transmitters. Both methods are for making a GPS lock tighter. The advantage depends on the application. DGPS won’t work outside of 200 miles from the transmitters, but WAAS can be blocked by things getting between your antenna and the satellite. (Like a bridge, sky scrapers etc…) The GP7000 uses WAAS to make the basic GPS fix tighter. The GP1850D uses DGPS. If you put a non-DGPS antenna like the GPA017 on the GP1850D, it will still acquire a basic GPS fix but will not have the tighter DGPS lock. (Because you don’t have a DGPS antenna for it to use) Since WAAS is more of a feature of the unit and not the antenna, the GP7000 has no problems using WAAS with the GPA017, 18, or 19. DGPS feature costs more because of the extra antenna requirement and the required internal DGPS receiver. WAAS is a lower cost method of obtaining a tight fix. It has become the more common method selected by newer units.
Thanks for the explanation above between GPS and WAAS both being satellite position receivers, one being newer w/more satellites + WWAS than the other with "D" for the additional Land transmitters for tighter fix.
****Then the second part of my question was if I sell the 1850D it WOULD be better to have the optional $250.+ GPA019 antenna on the 1850D unit for a tighter position.( shame the 1850D could also receive Loran).
The GP1850 has never been able to receive LORAN C transmissions. It is a GPS unit that can use an internal translation to show GPS position as a Loran number. (and still can, as does the GP7000) Only the "W" unit of the GP1850 will use WAAS fixing. For best fixing, using your 1850D, you want a DGPS antenna like the GPA019 or GPA018 with DGPS whip. With a GPA017, the 1850D will only get basic GPS fix. (no DGPS or WAAS).
Thanks again, For all your patience & help... I'm done, time to remove the GPA019 antenna from the boat while the weather is still in the 50's then I can put the GP-1850D w/C-Map NT on eBay with the proper antenna and wait till spring to install the GP-7000/GPA017 antenna.