GPS Antenna: Internal vs. External (?)

STeveZ

Seaman Apprentice
Joined
Sep 10, 2003
Messages
31
I am considering insalling Garmin GPSMAP 172C on the flybridge of my 28' Bertram. Is there any reason not to go with the internal antenna? Does the external antenna offer any advantage? I like the idea of the internal antenna's simplicity and the elimination of clutter (antenna/cable) on the bridge. The bridge is covered only by a canvas bimini if that's a consideration. Thanks in advance for your response.
 

Canuck 16

Petty Officer 2nd Class
Joined
Feb 25, 2004
Messages
102
Re: GPS Antenna: Internal vs. External (?)

I had the ploter your looking at and could never lock onto a WAAS satelite with it. I replaced it last year with a 182C with external antenna and have never had a problem aquiring WAAS.<br />It may just be my location, but you may want to try it out before you buy.<br /><br />Good luck... Canuck 16.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: GPS Antenna: Internal vs. External (?)

I agree the only posible issue would be the WAAS birds. The external antennas are more omni directional and can be mounted where nothing will block there veiw. Do not know your location but the farther north you are the weaker the singal. Actually the farther from the equator you are the weaker the signal.<br /><br />The canvas top is not an issue but your body between the unit and the WAAS bird is. Most internal antennas I have seen are somewhat dirrectional. Since the 2 WAAS birds are 23800 miles up and over the equator they are much harder to receive. Without the WAAS birds accuracy about 10 meters or 30 feet. With the WAAS bird accuracy about 3 meters or 10 feet. Really not that big a difference. The 24 non WASS birds are in low earth orbit and very strong when over head and you will have no trouble receiving.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: GPS Antenna: Internal vs. External (?)

Electronics topic.
 

imported_Curmudgeon

Chief Petty Officer
Joined
Sep 29, 2004
Messages
496
Re: GPS Antenna: Internal vs. External (?)

Originally posted by JB:<br /> Electronics topic.
Would that be why it's in the Electrics, Electronics and Trolling Motors (not engine) forum?
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: GPS Antenna: Internal vs. External (?)

Old Curmudgeon<br />The thread did not start in this forum. JB moved it here where it should be.
 

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: GPS Antenna: Internal vs. External (?)

Canuck16, where are you in B.C.? I have a Garmin 176C w/internal and have a hard time getting WAAS here in the northern end of SanJuans. I fish right by the border(EastPoint,Tumbo Channel, Petos) most of the time, so I use my old Loran which is probably more accurate anyway.
 

Canuck 16

Petty Officer 2nd Class
Joined
Feb 25, 2004
Messages
102
Re: GPS Antenna: Internal vs. External (?)

Gary, I'm about 80mi north of Vancouver.<br />I realy think the external antenna makes a big difference in being able to get a good lock on the WAAS bird.<br /><br />Cheers.
 

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: GPS Antenna: Internal vs. External (?)

Thanks, I just checked my unit to see if the flip up one will just unplug and it does, there is a terminal there for an antenna wire. Maybe I can find someone who has one on thier boat and hook mine into it so I can see for myself.
 
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