GPS Fishfinders - external vs internal antennas

gregk9 · July 02, 2010, 10:51:39 AM

Any preference here? I'm assuming the external would get better reception, no?

Todd Driscoll · July 02, 2010, 11:22:31 AM

Relative to Lowrance HDS units, the internal antennas function very well, even when flush mounted. Many users do prefer using an external LGC-4000 connected via the NMEA 2000 network, as these antennas provide a 5X/sec position update rate vs. 1X/sec for the HDS internals and the LGC-2000/3000s. This 5X/sec update is very beneficial when relatively stationary while fishing (i.e., dropshotting, fishing a brushpile), reduces the loss of direction and map rotating. And yes, on average your Estimated Position Error will be lower with the external 4000.

-Bryan- · July 07, 2010, 09:43:44 AM

love the internal on my HDS, hate the one on my 334c...was tempted to throw the 334c in the lake on numerous occaisions! Can't wait to upgrade the HDS7 to the 8 so I can put the 7 on the bow in place of the 334c.

coldfront · July 07, 2010, 10:24:45 AM

Quote from: Tracker03 on July 07, 2010, 09:43:44 AM
love the internal on my HDS, hate the one on my 334c...was tempted to throw the 334c in the lake on numerous occaisions! Can't wait to upgrade the HDS7 to the 8 so I can put the 7 on the bow in place of the 334c.

I currently have my console unit (HDS7) tied to an LGC-4000 on the transom. LOVE it... next upgrade in the spring will be to replace the LMS-480 on the front with an HDS5...then I'll have to figure out how to network the buggers...but I'll use the internal antennae 'up front'...

Baron49 · August 17, 2010, 12:36:44 PM

Tried using several internal antenna units form Lowrance and found the did not acquire and hold the signal that well. Switched them out for units that use an external antenna and have not had a single problem since.

Todd Driscoll · August 17, 2010, 03:30:00 PM

Baron, I assume you are referring to non-HDS units with internal antennas. The internals on the HDS units function very well, much better than older units.

coldfront · August 17, 2010, 08:04:58 PM

Quote from: Todd Driscoll on August 17, 2010, 03:30:00 PM
Baron, I assume you are referring to non-HDS units with internal antennas. The internals on the HDS units function very well, much better than older units.

Todd, I am u nder the impression that the internal antennas on the HDS units update 1x/second...which differs from the 5x/second on the LGC-4000 (external antenna)...

Am I not correct?

Todd Driscoll · August 18, 2010, 07:30:43 AM

Yes coldfront, that is correct. HDS internals update at the same rate as the LGC 2000s and 3000s (1X/sec). The update rate for the 4000 is 5X/sec.

coldfront · August 18, 2010, 07:46:58 AM

Quote from: Todd Driscoll on August 18, 2010, 07:30:43 AM
Yes coldfront, that is correct. HDS internals update at the same rate as the LGC 2000s and 3000s (1X/sec). The update rate for the 4000 is 5X/sec.

Thanks Todd...for 'me' that quicker update rate translates into less error on positioning...having said that...I ran the LGC-2000 for about 4 years...and in terms of 'finding spots' not sure there's a practical difference...

In terms of using the units (HDS + LGC) for collecting data, survey work...I WILL say this: it's excellent...and a significant improvement...

While I was very happy with the older LGC-2000 unit and have no problems running off the internal antenna...I 'do' appreciate and use the added capability of the LGC-4000...

I really like my Lowrance set up...I put it together to 'do' exactly what I want it to...

Baron49 · August 18, 2010, 10:36:44 AM

Quote from: Todd Driscoll on August 17, 2010, 03:30:00 PM
Baron, I assume you are referring to non-HDS units with internal antennas. The internals on the HDS units function very well, much better than older units.

Yes I am using a 3500C and a 520C with external antennas and very happy with them, they are older but serve me very well. Have some friends who bought the HDS units with the internal antenna and they are not happy with the way they work.

Someone told me that I should consider upgrading the both my units to the new LGC-4000 antenna as it is supposidly cheaper then buying the newer HDS units and makes a considerable difference in how well these older units will work.

cmansell · August 18, 2010, 11:55:03 AM

I have a Lowrance 522c with an internal antenna mounted at the console. I've never had any issues either picking up a signal or losing it once it aquires the position. I'm waiting on my wife to let me upgrade to HDS @ the console and bow. Just my 2 cents.

Baron49 · August 18, 2010, 01:15:52 PM

I tried the 522 and had problems with it accuring and holding a signal when down on the Hudson River and in several areas on the St. Lawrence river and in Canada. Once I switched to the 520C with the external antenna have not had any problems with the 520C in the past two years. That includes fishing from Canadian waters all the way down to Florida.