AntonRx Posted February 23, 2020 Report Share Posted February 23, 2020 He all. Didn’t see this anywhere (it might be common knowledge) but I swapped out my old gps for my 942xs. I still have the external antenna mounted on top of t-top from the old Gps. If I connect it to the 942, will it use the external “and” the internal antenna or does it just use one? Rather than remove it and have a hole up in the t-top fabric, is like to reuse it if possible. Quote Link to comment Share on other sites More sharing options...
DonV Posted February 23, 2020 Report Share Posted February 23, 2020 Did not know there was even a jack on the 942 for an external antenna? In any case look at page #2 in your owners manual to pick GPS source. In any case I'd use the internal only. Quote Link to comment Share on other sites More sharing options...
AntonRx Posted February 23, 2020 Author Report Share Posted February 23, 2020 8 minutes ago, DonV said: Did not know there was even a jack on the 942 for an external antenna? In any case look at page #2 in your owners manual to pick GPS source. In any case I'd use the internal only. I think it has a coaxial connection of some kind. Haven’t really looked at it. Will assess today. Quote Link to comment Share on other sites More sharing options...
FINCHASER Posted February 23, 2020 Report Share Posted February 23, 2020 I know nothing about Garmin but most all external GPS antennas are connected thru a NMEA network nowadays 1 Quote Link to comment Share on other sites More sharing options...
bernieNC Posted February 23, 2020 Report Share Posted February 23, 2020 1 hour ago, FINCHASER said: I know nothing about Garmin but most all external GPS antennas are connected thru a NMEA network nowadays This. http://static.garmin.com/pumac/GPSMAP_7x2-9x2_Install_EN-US.pdf Page 4 1 Quote Link to comment Share on other sites More sharing options...
fin-addict Posted February 23, 2020 Report Share Posted February 23, 2020 Have an old gps antenna on my t also. Just forget it’s there and use the internal, no need for both. The old one more than likely will not work with the new unit me thinks. Good luck Quote Link to comment Share on other sites More sharing options...
Hutch03 Posted February 24, 2020 Report Share Posted February 24, 2020 My old 741xs has an internal antenna only Quote Link to comment Share on other sites More sharing options...
jchern Posted February 24, 2020 Report Share Posted February 24, 2020 When I upgraded my gps to a 1242xsv, Garmin customer support directed me to use the internal antena vs the external one. Works great and never looked back. Quote Link to comment Share on other sites More sharing options...
FINCHASER Posted February 24, 2020 Report Share Posted February 24, 2020 I for one would check the refresh rate on the internal vs the external.... if they are the same if the external has a better refresh rate itd give you better performance if you use the plotter for nav Quote Link to comment Share on other sites More sharing options...
smilemaker Posted February 24, 2020 Report Share Posted February 24, 2020 Another reason to use an external antenna is the addition of an electronic compass. It is often beneficial to know the heading of the boat on the gps while drift fishing or just anchored. No electronic compass on the internal antenna. Quote Link to comment Share on other sites More sharing options...
fin-addict Posted February 24, 2020 Report Share Posted February 24, 2020 4 hours ago, smilemaker said: Another reason to use an external antenna is the addition of an electronic compass. It is often beneficial to know the heading of the boat on the gps while drift fishing or just anchored. No electronic compass on the internal antenna. My garmin internal antenna gps shows compass heading and has a compass strip at top of chart. Use it for drift fishing at times Quote Link to comment Share on other sites More sharing options...
smilemaker Posted February 24, 2020 Report Share Posted February 24, 2020 There is a big difference in an electronic compass and a bearing reading on the gps. The electronic compass tells you which way the boat is facing regardless of movement. The bearing on the gps tells you which direction you are going regardless of the boats direction. If you are drifting sideways in a current at 6 knots the bearing on the gps shows the boat moving straight whereas the electronic compas will show the boat in the proper orientation moving sideways on the chart. Sometimes it can be important. Quote Link to comment Share on other sites More sharing options...
FINCHASER Posted February 24, 2020 Report Share Posted February 24, 2020 A heading sensor is a huge benefit so yea If the antenna OP is referring to has it the decision is ez, go with it.... I wont own a boat without one Quote Link to comment Share on other sites More sharing options...
smilemaker Posted February 24, 2020 Report Share Posted February 24, 2020 Yes I am assuming if you put an external antenna on you would be smart enough to put one with the electronic compas built in. Two birds with one stone Quote Link to comment Share on other sites More sharing options...
fin-addict Posted February 25, 2020 Report Share Posted February 25, 2020 My wrong then. Why does an ext show it and an int does not. When drifting over the deep holes in Charlotte Harbor it shows my boat drifting in the direction it’s going, so confused right now. Lol Quote Link to comment Share on other sites More sharing options...
FINCHASER Posted February 25, 2020 Report Share Posted February 25, 2020 Its not the difference between internal/ external its the hardware it contains, a regular GPS will always show the bow of your boat pointing in the direction the boat is moving. Your MFD or GPS antenna has no clue where your bow is therefore it cannot show you on the graph exactly how your boats positioned on the water. A heading sensor must be oriented so it knows which direction the bow is and has the electronic compass which solves this issue. I figured this out when I 1st started bottom fishing. Without heading sensor it was difficult at best to set up and anchor on structure as I couldnt get accurate stable reading and once anchored the graph would show the structure at point x relative to the boat but in reality it was not there Quote Link to comment Share on other sites More sharing options...
fin-addict Posted February 25, 2020 Report Share Posted February 25, 2020 13 hours ago, FINCHASER said: Its not the difference between internal/ external its the hardware it contains, a regular GPS will always show the bow of your boat pointing in the direction the boat is moving. Your MFD or GPS antenna has no clue where your bow is therefore it cannot show you on the graph exactly how your boats positioned on the water. A heading sensor must be oriented so it knows which direction the bow is and has the electronic compass which solves this issue. I figured this out when I 1st started bottom fishing. Without heading sensor it was difficult at best to set up and anchor on structure as I couldnt get accurate stable reading and once anchored the graph would show the structure at point x relative to the boat but in reality it was not there Just did some research about my garmin unit. It states it does have an electronic compass built in. On my chart it shows the direction of where the bow is pointing at any given time. Example at my dock it shows the bow pointing down my canal and that is how it’s tied to my dock. What am I missing. Quote Link to comment Share on other sites More sharing options...
FINCHASER Posted February 25, 2020 Report Share Posted February 25, 2020 Dunno... not familiar at all with Garmin. Times have changed maybe they put them in units now a days I know that didnt used to be the case Quote Link to comment Share on other sites More sharing options...
FINCHASER Posted February 25, 2020 Report Share Posted February 25, 2020 Old info but explains what Ive been trying to http://www.gpsreview.net/electronic-compass/ Quote Link to comment Share on other sites More sharing options...
bernieNC Posted February 25, 2020 Report Share Posted February 25, 2020 Have been running with Garmins for over 25 years. Never found a need for an external antenna. Quote Link to comment Share on other sites More sharing options...
fin-addict Posted February 25, 2020 Report Share Posted February 25, 2020 9 minutes ago, bernieNC said: Have been running with Garmins for over 25 years. Never found a need for an external antenna. X2 Quote Link to comment Share on other sites More sharing options...
fin-addict Posted February 25, 2020 Report Share Posted February 25, 2020 11 minutes ago, FINCHASER said: Old info but explains what Ive been trying to http://www.gpsreview.net/electronic-compass/ I read that exact same article this morning, thanks much Chaser. Still confused but not going to loose sleep over it. If I don’t have it, don’t need it. LOL. 😀⚓️ Fin 1 Quote Link to comment Share on other sites More sharing options...
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