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Author Topic:   LOWRANCE LMS-334C-iGPS
davej14 posted 03-31-2006 04:49 AM ET (US)   Profile for davej14   Send Email to davej14  
I am about ready to purchase the Lowrance LMS-334C-iGPS ($649.00 at Bass Pro)and would appreciate any comments about this unit's performance. I want to keep the cost around $700.00, but if there are superior units out there I would consider paying a bit more. I need to have excellent chart capability of inland lakes and canals in Upstate NY.

Before I make the commitment are there any other suggestions?

jimh posted 03-31-2006 05:55 AM ET (US)     Profile for jimh  Send Email to jimh     
The April 2006 issue of POWERBOAT REPORTS contains a comparison of four combination chart plotter-GPS-SONAR units in that price range. The editors chose an LOWRANCE as their best pick, but it was a slightly different model.

I have noticed that LOWRANCE model numbers change every six weeks.

jimh posted 03-31-2006 06:12 AM ET (US)     Profile for jimh  Send Email to jimh     
I did some research on the LOWRANCE model in the test report. It was the


which was named the top-performer by POWERBOAT REPORTS.

This unit differs from your proposed model LMS-334C-iGPS as follows:

The LMS-337C DF has NMEA-2000 outputs/inputs.
The LMS-334C-iGPS has no NMEA outputs or inputs.

The LMS-337C DF has an external GPS receiver/antenna.
The LMS-334C-iGPS has an internal GPS receiver/antenna.

The LMS-337C DF has dual frequency transducer
The LMS-334C-iGPS has a single frequency transducer.

I found the LOWRANCE website was very well organized and made comparison of the features easy using this presentation:

It seems that the purchase of a particular brand of chart plotter tends to lock you into a particular brand of digital cartography. You should assess the cartography available with the LOWRANCE unit to see if it fits your needs. In my unscientific survey opinion, it looks like LOWRANCE gives you the most cartography for your money.

davej14 posted 03-31-2006 05:52 PM ET (US)     Profile for davej14  Send Email to davej14     

I have done quite a bit of research on the Lowrance offering. Their website is misleading because both these units have NMEA capability. They both have one I/O port for NMEA 0183 in addition to the Lowrance NMEA 2000 bus. This is not clear anywhere in their literature. I was at BassPro again today and confirmed this is correct.

I was considering the LMS-337 DF which has a sister unit with an internal gps antennae called the LMS-339 DF igps because of the dual frequency transducer. This makes the transducer quite large and I'm not sure it would give me much benefit since I only will be in fresh water.

Lowrance does seem to have the best cartography for small lakes as well.

Do you think the dual frequency transducer is a benefit? I have no experience other than with a single frequency transducer.

Bulldog posted 03-31-2006 07:55 PM ET (US)     Profile for Bulldog  Send Email to Bulldog     
I've decided to go with the 337 mainly, for the transducer which also gives you temp. and speed. I haven't found the 337 for less then $649 on line and every where else is about $699, plus about $200 to get a twin engine fuel flow sensor setup that ties into the 337, tough to beat! Cabela's site has the fuel flow sensors and gauges for sale now, pretty neat! I live 20 minutes from a Cabela's which makes it hard to save up those Cabela's dollars!..............Jack
jimh posted 03-31-2006 08:11 PM ET (US)     Profile for jimh  Send Email to jimh     
Using the 200-kHz skimmer transducer I was able to get bottom echoes in 400-feet of saltwater, but not reliably. If you are a freshwater boater and normally in less than 200-feet of water, the 200-kHz transducer should be good.

Getting all the signals (SONAR, Speed, Temp) in one transducer is a nice bonus!

I am glad to hear about the NMEA output from the LMS-334C-iGPS. That is nice if you want to get the depth reading into some other device.

davej14 posted 04-01-2006 08:57 AM ET (US)     Profile for davej14  Send Email to davej14     
The LMS-339C DF igps is the same as the 337c but it has an internal gps antennae. You may want to consider that to reduce dash clutter even more. I believe the price is the same. Both these units come with an external transom mount paddle wheel for speed sense and distance over water. The accuracy of these sensors is in question in other posts on this site, especially at higher speed. The transducer has the temp sensor built into it. Be aware that the transducer for the dual frequency units is quite large in comparison to the single frequency units. The single frequency units do not come with the external paddle wheel.

I plan to start fishing with a down rigger this year so I want to be able to "see" the weight. The finger lakes in Upstate NY are quite deep, 500 to 600 ft. The dual frequency has appeal, but at 200 kHz this transducer has a 40 degree cone angle while at 50 kHz it has a 90 degree cone angle. The single frequency 200 kHz transducer has a 60 degree cone angle. Now I am really confused. With a dual frequency unit do you lose resolution at the lower frequency? Do both frequencies work simultaneously or do you have to switch back and forth?

Roarque posted 04-01-2006 11:59 AM ET (US)     Profile for Roarque  Send Email to Roarque     
dave, if your boat is open ( outrage, montauk) center console style, you should buy the LMS-339CDF model because it has the GPS antenna built into the hardware - no need to mount an external antenna. This saves space on the center console dash mount.

I installed this unit on my Outrage 18 recently and it works well. It replaced a Lowrance X88 which had a DF transducer and I discovered that the transducer from the X88 was identical to the transducer delivered with the 339CDF, so I didn't replace it. Excellent!!

Bulldog posted 04-01-2006 04:48 PM ET (US)     Profile for Bulldog  Send Email to Bulldog     
I'm thinking of the 337 because I have a Revenge model with cabin, and am thinking that it might work in the wiring compartment just inside the windshield if not, perhaps in the cabin , with just a layer of fiberglass between it and the sky or I'll have to get a mount. From past discussions it sounds like there are a lot of guys with center consoles with the antenna for the GPS inside the console. My GPS wil be recessed in the console similar to the depth finder it will be replacing. If I didn't have the recessed issue and windshield frame I would go with the 339, less connections to fail, and easy to take home and play with setting up!.....Jack
jmorgan40 posted 04-01-2006 09:12 PM ET (US)     Profile for jmorgan40  Send Email to jmorgan40     
I buy all my electronics from They have both the 337 and the 339 for $645. Great people to deal with.
Marsh posted 04-02-2006 11:08 AM ET (US)     Profile for Marsh  Send Email to Marsh     
I have the Lowrance 337, and find the screen too small for these old eyes. Have to put on my specs to read it. I suspect I would have the same trouble with anything short of a 27 inch flat panel, LOL.

Also, there are only minimal maps that come standard with the unit. To be of any navigational use at all, I found that I had to buy separate memory card chips for the areas I intended to fish. I bought the elite fishing hot spots maps for $99.00 each. Had to get two chips, because the areas I fish (Louisiana Gulf coast, and Tennessee River inland waterways)were not available on a single card.

I paid $699 for mine (plus shipping?), plus the two cards at $99.00, so I am up to a bit over $900 or so. And I still carry charts anyways.

Unit was easy to install once I coaxed the 'ducer cable through the rigging tunnel...took LOTS of effort, and LOTS of dishwashing liquid as lubricant. I tugged, pushed, pulled on the fish tape off and on for several evenings after work. Finnaly, it slid through. Persistence pays.

One other note: the instructions said that the unit could be wired either directly to the battery, or to a switch. Wired directly to the battery, the unit drained my battery after 3 weeks of garage time. Better to connect to ACC switch, if you have one.


wwbach posted 04-03-2006 11:27 PM ET (US)     Profile for wwbach  Send Email to wwbach     
I just bought and installed a LMS-334C-iGPS. I bought from broken leg dave's:

for under $600 but I see it is now $609 (w/ transducer). The transducer does provide temp and holds bottom at around 47.8 mph in shallow water (just spent a week in Florida). My initial impressions are favorable. I am a little disappointed with the screen in direct sunlight but I have nothing to compare it with. It seems to be pretty easy to use based on previous experience with garmin and raymarine equipment. I haven't picked up a map chip yet so I can't comment on that part of the unit.

-- Bud

Backlash posted 04-04-2006 09:40 AM ET (US)     Profile for Backlash  Send Email to Backlash     
Another important consideration, not mentioned here in comparing the 334C and 337C, is that the 334C has 2400 watts (peak-to-peak) of power and the 337C has 4000 watts.

On my old LMS-350a sonar with dual frequency transducer, both frequencies can be displayed in split screen mode. I would imagine the 337C is the same. The 50 kHz, with 90 degree cone angle would be better for picking up your downrigger weights. I think I would go with the 337C - only $50 more than the 334C.


JMARTIN posted 04-04-2006 12:31 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
I have the 337 CDF. You do not get all the signals from one transducer. Sonar is the transducer, speed and temp is a paddle wheel. You have two cables and more holes in the transom. In hindsite, I would not have put the paddle wheel on. The GPS gives you speed over land, the paddle wheel gives you speed over water. I do not care how fast I am going over the water. I do not care what the temperature is either.

Pros and cons. The sonar is pretty amazing. You can see the downrigger go down. Being able to pick up the bottom at over 500 feet is not really needed. I can not fish down there anyhow. The external antenna is just something else to get a line caught on, and another cable and more holes, but it works well.

The canned maps for the GPS were a joke. I have had placemats at restuarants with better detail on them. The chip I bought is terrific. It was pricey, I think I got took at Boaters Worst, I mean World, but I was in a hurry.
I do not even know what it is, Navionics?. About 180 bucks if I remember correctly. It plugged right in and started working, so no complaints.

The screen is hard for me to see with my sunglasses on. A commen problem with polarized lenses I think.

The split screen is really cool. I seldom use it for fishing, but for navigation, it's killer. Let's say I am going into a bay I have not been in before. I put one screen on automatic bottom locating sonar. The other screen on the GPS map. The map shows that the channel shallows on the port side clear to the middle of the channel. On the map you see you are approaching the shallow area, your sonar confirms you are shallowing. You make turn to what the maps says is deeper water, the sonar confirms you are getting deeper. Very cool for some of the tricky, narrow, rocky and current infected spots we have up here in the PNW.

Lowrances support team has been terrific also. I had a problem which they fixed and they even had a couple of follow up calls to make sure everything was working. John

davej14 posted 04-04-2006 04:21 PM ET (US)     Profile for davej14  Send Email to davej14     
Two questions for those with dual frequency Lowrance sonars.

1. Can you actually display the sonar outputs from the 50kHz and 200kHz simultaneously on a split screen? This would be kind of neat. Otherwise the 200 kHz beam angle is a rather narrow 40 degrees.

2. How does the feature for following a return track work in practice. I am confused about how this works because the "navigation" screen looks like it is just a compass and not a chart. Am I missing something?

I appreciate your help.

JMARTIN posted 04-04-2006 04:56 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
Yes, you can display both sonars on a split screen

You can change the navigation screen. You can have a map, a pointer thingy if you have set a waypoint to go to. A bunch of other stuff. What I have found works best for me for a return track is called "trails". The GPS remembers where you have been and makes a trail on the map. Just follow the trail home. Works real well if I have gone into a tricky entrance little bay to spend the night. Next morning, my trail shows me the way out. Still have to remember the tide is different.

When I am fishing, even though I am using just the sonar, I am still recording trails. If I find a hot spot for fish, I can go right back to the same spot following the trail. I think I could set a waypoint and come back to the same spot also, but I am still learning.

Go play here. John

Chuck Tribolet posted 04-05-2006 07:22 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
What Lowrance calls a "trail", Garmin calls a "track". And
some folks call "bread crumbs". ;-)

Yes, if you set a way point you could return to it. I often
use the MOB (Man Overboard) function to quickly set a
waypoint. I can always rename it if I want to keep it, and
it's good practice for when your buddy DOES fall overboard.

If you are following the return track, it's like following
a route, just keep the arrow pointing straight ahead.

Dunno about Lowrance, but the Garmin integrated GPS/fishfinder
units allow you to point at a spot in the FISHFINDER trace,
and set a waypoint for the GPS (for each column of fishfinder
pixels, they have remembered the lat/lon). This is really
handy if you go over some bump of structure (or I guess a
bait ball).


davej14 posted 04-12-2006 08:16 PM ET (US)     Profile for davej14  Send Email to davej14     

Have you actually tried to display data at 50 kHz and 200 kHz simultaneously on the split screen of the LMS-337c ?? The reason I ask is that I called Lowrance technical support today to help me with my decision to buy either the single frequency 200kHz LMS-334iGPS or the dual frequency LMS-339c. They told me that the dual frequency units were only capable of displaying one frequency at a time.

I have decided to purchase the single frequency unit because the resolution at 200 kHz is better and it has a wider beam angle at 200 kHz than the dual frequency unit. I only fish fresh water so I would only miss the 50 kHz capability about 1% of the time I am fishing.

JMARTIN posted 04-13-2006 12:30 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
I have not done it, just read about it I think. I will look in the book again. John
JMARTIN posted 04-13-2006 01:36 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
There are instructions in the book for split ferquency sonar chart, LMS 337CDF only, on page 87. You can download the owners manual on line from the Lowrance site. John
davej14 posted 04-13-2006 06:11 PM ET (US)     Profile for davej14  Send Email to davej14     

You are absolutely right. the manual for the 339c clearly shows a split sonar screen with one side at 50 kHz and the other at 200 kHz. Once again this site excels in information accuracy.

Now I am quite disappointed with the Lowrance technical support person I talked to. Not only did it take 25 minutes to ring through, she told me specifically that I could only display one frequency at a time in dual sonar mode. Today I purchased a 334c single frequency unit and now I need to rethink if this was the right thing to do.

I think I'll call Lowrance again to talk to a more senior person about the 200 kHz performance of the single vs. dual frequency transducer.

wwbach posted 04-16-2006 09:28 AM ET (US)     Profile for wwbach  Send Email to wwbach     
In a previous post, I noted:

"I am a little disappointed with the screen in direct sunlight "

I feel a little dumb but I figured out if you push the power button with the unit on it toggles between three different brightness levels. I am no longer disappointed. It looks great! A nice unit for the price I think. I am having a little problem with the unit losing position but a google search indicates that it takes a while for the unit to learn where the satellites are. I hope this will go away after a while. – Bud

davej14 posted 04-16-2006 11:54 AM ET (US)     Profile for davej14  Send Email to davej14     
Bud, Glad to hear you are no longer concerned with the brightness of the display. There are so.... many options for these new electronics devices we all feel dumb about the capabilities.

When you say you are having problems with the unit "losing position" can you elaborate? If you are talking about when you first turn on the unit, I would expect it to take a few minutes to get a lock on all the satellites. After that it shouldn't lose its way.

wwbach posted 04-17-2006 12:45 AM ET (US)     Profile for wwbach  Send Email to wwbach     
After being on for a couple of hours of use I start to get brief cycles of "lost signal" "aquired signal" type alerts on the screen. It doesn't happen at startup. I need to do some more research and call support. It could be an installation issue or something else silly. It hasn't been a priority to figure out as of yet but I need to do it soon. -- Bud
Chuck Tribolet posted 04-17-2006 08:54 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
When you loose signal, is there anything overhead? It doesn't
take much to block the weak signal from the satellites. Even
your hand will knock it down by about half.

And check the wiring.


davej14 posted 04-17-2006 09:51 AM ET (US)     Profile for davej14  Send Email to davej14     
This operation is not what I would expect. Once satellite links have been established, you should not experience a complete loss of signal in an open boat. If you are not experiencing intermittent power to the unit then I suspect something is wrong with it. For example, I have a handheld Garmin eTrex Vista that I have used for two years on my boat and I never experienced a similar loss of signal. I even use it in the car positioned in a cup holder in the center console and it still maintains a reliable satellite link.
wwbach posted 04-17-2006 01:24 PM ET (US)     Profile for wwbach  Send Email to wwbach     
Chuck, Nothing overhead. Mounted on the console of a 22 Outrage.

davej14, I agree this shouldn't be happening. I've never seen this with other units I've used (Garmin and Raymarine). I need to call but I won't have time until later this week.

I'll let you guys know.

-- Bud

Reckless posted 05-09-2006 12:16 AM ET (US)     Profile for Reckless  Send Email to Reckless     

I just bought the 334c today. I was concerned because I read some postings where people were having trouble with their units holding position even in open cockpit boats. Apparently early models have this problem but they have corrected the problem with their current production. This is straight from Lowrance tech support. Try this, if you keep the unit as close to upright as possible, it will help. If you send the unit to Lowrance, they have a simple fix to correct the problem (from tech support). I plan to simply take the thing back if I am having the problem. I got an open box deal from a local dealer, that is the only reason I bought it.

Hope it helps.

wwbach posted 05-09-2006 12:40 AM ET (US)     Profile for wwbach  Send Email to wwbach     
Thanks Reckless. Last time out I left it on in the driveway for a couple of hours and no issues and it was perfect for 8 hours on the water. If I have another glitch, I'll get serious and call to see what's up. I see they have a software update I'll probably grab too. -- Bud
davej14 posted 05-09-2006 09:26 AM ET (US)     Profile for davej14  Send Email to davej14     
As an experiment I took the LMS-334c for a ride in my car along side my handheld Garmin etrex Vista. The LMS-334c had slightly less capability to maintain satellite lock but it was very similar to the etrex. I could be that the position accounted for the slight difference. Both units were sitting on the center console of my Volvo V70 wagon with all windows and the sunroof closed. This is a pretty extreme test so I do not anticipate any issue on my boat.

Did Lowrance give a serial number cutoff for their "improved" antenna ?

Reckless posted 05-09-2006 11:39 PM ET (US)     Profile for Reckless  Send Email to Reckless     
I asked Lowrance about serial numbers and they told me there is no way of determining which unit you have. You just have to test it out and see.

Thanks Bud for informing us on your experience. I would likely have seen it loose lock the first few times and taken the unit back. This time, I will leave it on for a while before judging.

Also, I read the manual and it appears that you can change the setting from internal antenna to external antenna and you effectively have the same unit as the LMS-332c but with the option of being able to take it with you. Problem is those LCG-2000 antennas are about $200.


duckear posted 05-11-2006 08:17 PM ET (US)     Profile for duckear  Send Email to duckear     

I recently bought a 334C IGPS with transducer for $567 with free shipping. I spoke with Lowrance about the dual freq/ single freq transducer and he told me the narrow angle at 200kHz on the dual freq 'ducer would be nearly worthless in most freshwater is just too narrow.

montauk steve posted 05-11-2006 10:26 PM ET (US)     Profile for montauk steve  Send Email to montauk steve     
I just bought the 332c for a bit more.

Since I opted for the external gps ant. what can i use to attach the ant. to the rail above the helm??

I plan on installing it this weekend.

duckear posted 05-11-2006 11:49 PM ET (US)     Profile for duckear  Send Email to duckear     
I also picked up a ACR Aquafix with GPS for $540

Chuck Tribolet posted 05-11-2006 11:55 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Most GPS antennas have a standard 1-inch thread like a VHF
antenna. If it does, the electronics section of your
favorite chandlery will have several options to bolt it to
the rail.


jimh posted 05-11-2006 11:58 PM ET (US)     Profile for jimh  Send Email to jimh     
A good way to locate on-line sellers (of anything) is to use FROGGLE.COM
JBG777 posted 05-14-2006 08:16 AM ET (US)     Profile for JBG777  Send Email to JBG777     
After reading through this thread I'm still not sure if I made the right decision purchasing the 334c. I have a Montauk 170 and will fish no deeper than 100ft in Saltwater.
The dealer told me that the dual freq. would not be beneficial to me. I was ready to buy the 339c and he talked me out of it. Any thoughts?
highanddry posted 05-14-2006 01:39 PM ET (US)     Profile for highanddry  Send Email to highanddry     
My dealer told me the opposite concerning the DF, I am sure there is an expert here. I cannot answer your question regarding the DF but he told me that in saltwater the water column can often be highly aerated and ful of plankton and other such things that the higher frequency will be almost totally absorbed. The lower frequency has more penetration to get through this stuff.

Why would you not want t opay the extra 50 bucksand get the DF? Is there something I am missing here--just in case you need it.

I am pretty sure my friend with a Trophy CC we met last summer is running two transducers on his boat for one unit. I am not sure if he has a switch to select one or the other or if he reaches in the console and plugs and unplugs.J

JBG777 posted 05-14-2006 02:36 PM ET (US)     Profile for JBG777  Send Email to JBG777     
No you are not missing anything and I was totally prepared to buy the 339C. It is just going to be a challenge to exchange the unit. If I really don't need the two freq. then I would concider keeping the unit that I already purchased.
davej14 posted 05-15-2006 09:54 AM ET (US)     Profile for davej14  Send Email to davej14     

The 200 kHz transducer will give you better resolution than the 50 kHz transducer. The dual frequency transducer of the LMS-339 has a 200kHz cone angle of 12 degrees while the single frequency transducer of the LMS-334 has a cone angle of 20 degrees. You will get more "visible filed" with the single frequency 200 kHz transducer and if you do not need to go beyond 100 feet or track down-riggers with the 50 kHz cone angle of 35 degrees you probably have the right unit.

JBG777 posted 05-18-2006 09:49 AM ET (US)     Profile for JBG777  Send Email to JBG777     
I spoke with Lowrance customer service and they confirmed that I made the right decision with the 334 based off the fact that I will be in depths less than 100ft with no downriggers.

Jimbob posted 06-01-2006 11:35 PM ET (US)     Profile for Jimbob  Send Email to Jimbob     
I purchased a LMS-334iGPS on April 2, 2006. About the third time out, I started losing satellite lock. After about three times of this, I sent it off to Lowrance, and they sent me a new unit. Took the new one out yesterday and guess what??? Same thing happened with the new unit. My
$100 Garmin GPS 12 locks on to position in 45 seconds in my front yard under my huge live oaks. The Lowrance will not even lock onto position in the same area. In the open part of my yard, the Lowrance takes 5-10 minutes to lock, and will not stay locked on. I've only been able to acquire position in the wide open with no obstructions.
jimh posted 06-02-2006 12:02 AM ET (US)     Profile for jimh  Send Email to jimh     
The signals received by a GPS are transmitted with a spread spectrum technique, and, as you mention, it is crucial that the demodulator obtain and retain synchronization with the desired signal. Because there are so many satelllites in the constellation of GPS orbits, the receiver needs some help in determining which satellite to look for. There is generally an ephemeris built into the receiver which knows the satellite orbits. If you seed the receiver with the approximate time and location, it will be able to look up the satellites in the ephemeris and deduce which ones might be in view. It then tries to acquire the signals from those satellites.

When a receiver cannot obtain lock, it could be caused by many things. The fundamental problem could be received signal levels are too low. If the receiver does not have good time and current location data, it may be looking for the wrong satellites. This will increase the time to find and lock onto the satellites that actually are in view.

The GPS device is able to bootstrap itself into greater precision. Once it has acquired a couple of satellites, it can deduce the time with very high precision. Once it has three satellites it can deduce its position with very high precision. And from there it can look for and acquire more satellites as their orbits bring them into view, all as predicted by the ephemeris. With four satellites in lock it can deduce its elevation. Even more satellites can be acquired and tracked in case a signal is lost from one of the others.

This is all a quite astonishing process that we have come to take for granted, until it goes wrong. There is likely some defect in the LMS-334iGPS which is inhibiting this from operating properly. It sounds like time for a call to the manufacturer.

The technique of spread spectrum communications was first patented by movie actress Hedy Lamarr and her composer friend George Antheil in the 1940's. See for details. Their story is equally as amazing as the GPS itself!

wwbach posted 06-02-2006 04:04 PM ET (US)     Profile for wwbach  Send Email to wwbach     
My LMS 334c iGPS is on the way back to Lowrance after a call to them yesterday. I hope I don't have the same experience as Jimbob. -- Bud
Jake1 posted 06-11-2006 12:53 PM ET (US)     Profile for Jake1  Send Email to Jake1     
I have had the same trouble with my new 334c loosing position in the last week since installation. I have it mounted on the bow and use it on my electric trolling motor so I didn't want to mount another external GPS antenna. It may work for 2 or 3 hours and then loose position and become unusable for over an hour! At the same time. I have a LCX 19c with an external antenna that never looses position and is mounted on the console. The antenna is mounted less than 6 feet from the 334c. I have owned 9 different Lowrance units over the years and they have been really good with tech support, but I must say that this unit disappoints me and I would buy a 332c with the external antenna if I had it to do over again.
reitzcd posted 06-12-2006 10:47 PM ET (US)     Profile for reitzcd  Send Email to reitzcd     
Just tried out a 339i from Lowrance. Totally worthless. Could not find satellites if they fell out of the sky and landed on this piece of garbage. Garmin unit 100% reliable - same day, same boat.

Lowrance Phone support told me to take it back to the store and try to get one with an external antenna ..... Cabela's told me to call Lowrance.

Wish I had read this website before I purchased.

davej14 posted 06-13-2006 12:45 AM ET (US)     Profile for davej14  Send Email to davej14     
Thanks for all the inputs. I have the LMS334 ready to install in the next week to ten days. Now I am wondering if it would be a mistake. I guess I'll call Lowrance and discuss this problem with them while I can still return the unused unit. I'll post the remarks I get from Lowrance.

Is anyone out there having success with the Lowrance units with internal GPS antennas?

duckear posted 06-13-2006 07:56 PM ET (US)     Profile for duckear  Send Email to duckear     
I put the 334 on my Dauntless and have had it out for one full day. The cold start at the beginning of the day took about 2 minutes for a fix and never lost the signal all day. And my bimini top was up all day as well. Happy camper here for now. Hope you get it sorted out soon.

davej14 posted 06-15-2006 02:14 PM ET (US)     Profile for davej14  Send Email to davej14     
For those having trouble with the internal antenna on the LMS334-igps and LMS339-igps units there appears to be an alternative. If you cannot return the unit for replacement or receive satisfaction from Lowrance or the retailer, it is possible to add an LMS-2000 external antenna to these units via the Lowrance bus. Cheetah_NMEA2000Devices_0154-561_011206.pdf

Please keep us aware of your progress.

JMARTIN posted 06-15-2006 02:49 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
The LMS 337 CDF that I have with an external antenna, has never lost signal once it aquires it. Takes about a minute when you first turn it on to get the signal.

Sorry to hear that the internal antennas from Lowrance seem to have some hook up problems. John

Screamer posted 06-21-2006 10:14 AM ET (US)     Profile for Screamer  Send Email to Screamer     
I'm looking to buy the LMS339 unit. I have a center console, so i'm leaning towards the internal antenna. I'm a little weary of it after reading some of the posts. Above Davej14 posted a web site to set it up to link the LMS-2000 external antenna. Has anyone tried this yet? If so, how did it perform. Thanks!
bubblehead posted 06-21-2006 04:49 PM ET (US)     Profile for bubblehead  Send Email to bubblehead     
I installed a 332c last summer. It works great. Very fast fix on satellites and very reliable and repeatable. I fish in the mid atlantic and am also never over 100 feet deep. The single 200 mz transducer is fine. I fish 100 days a year in all kinds of conditions and have never had a problem with the signal not getting to the bottom due to plankton etc. Plus the cone angle on the 50 mz is so narrow like 8 degrees that in shallow water youre looking at about a 8 foot wide circle on the bottom.
wwbach posted 06-23-2006 04:21 PM ET (US)     Profile for wwbach  Send Email to wwbach     
Got my LMS-334c back today - 3 weeks to the day after I shipped it. It is actually a new or refurb as my favorite scratches in the case are missing. I had hoped for quicker turnaround but I haven't been in the boat since then anyway. I'll report back Monday with results. -- Bud
JBG777 posted 06-25-2006 09:01 AM ET (US)     Profile for JBG777  Send Email to JBG777     
For those of you that have this unit, I am experiencing a lack of detail with my navionics mid atlantic gold chip.
I have some detail but not nearly the level that I saw when I purchased the unit. I have played with the maps but I'm assuming it's a settings issue. Thanks for your help.


davej14 posted 06-25-2006 10:16 AM ET (US)     Profile for davej14  Send Email to davej14     

Did you "load" the map data after installing the chip? You need to do this to access the data on the chip.


rumn8r posted 06-25-2006 11:15 AM ET (US)     Profile for rumn8r  Send Email to rumn8r     
I just purchased a 150 Montauk and I am trying to decide among the Lowrance 332, 334, 337, and 339. I will be fishing fresh water only and will only occassionally fish for salmon and lake trout with downriggers but I would like to see the weight drop. I would prefer an internal antennae so I don't have to deal with mounting the external but also don't want to deal with poor reception. Should I choose dual frequency or single? What about internal vs. external?

I'm confused about the temp and speed sensors. Does the paddlewheel come with all units or just the dual frequency units? Is the temp sensor in the paddlewheel unit or the sonar transducer?


davej14 posted 06-26-2006 02:05 PM ET (US)     Profile for davej14  Send Email to davej14     

It is impossible to find the P/N of the transducers that come with these models on the Lowrance web site. I called Lowrance and here is what I determined:

LMS337C-DF and LMS339C-DF-iGPS both come with a Lowrance dual frequency transducer P/N 106-77 (HST-DFSBL). Lowrance does not recommend the dual frequency transducer for fresh water because the high definition 200 kHz element has a very narrow cone angle of 12 degrees. This makes it pretty useless in shallow water. While the 50 kHz transducer has a much wider cone angle it lacks definition. This transducer is recommended for deep water only.

LMS-332C and LMS334C-GPS both come with a Lowrance single frequency transducer P/N 106-72 (HST-WSBL). The 200 kHz element in this transducer has a cone angle of 20 degrees but it also has a secondary lobe that can provide upo to 60 degrees of coverage.

Both the single and dual frequency transducers come with a built in temperature sensor.

Only the dual frequency units (LMS337C-DF & LMS 339c-DF iGPS) come with a paddle wheel speed sensor.

When I talked to Lowrance technical support they would not admit to any problems with the internal antenna. This is in conflict with what has been reported on this site and customer reviews I just read on the Bass Pro site. It will be interesting to read wwbach's report on his replacement iGPS unit.

I have decided to return the LMS-334C-iGPS I have (not yet installed) and exchange it for the LMS-332C with the external antenna, which has excellent reviews.

Another reason for going with the unit having an external antenna is that GPS data from the internal antenna is NOT available to a NMEA-2000 data bus, while the LGC2000 external antenna is already on the bus. The external units also come with the start of a NWEA-2000 bus to interface to the LMS2000 external antenna, while these are items you would have to purchase to hook a unit with an internal antenna to the bus. Both units do have a single NMEA-0183 I/O interface.

wwbach posted 06-26-2006 05:42 PM ET (US)     Profile for wwbach  Send Email to wwbach     
LMS-334c iGPS is back in the boat. Quick to aquire signal and no lost signals (yet). Put me on these nice fish off New Buffalo, MI:

Sorry, no pictures of the gps/finder. For what it is worth, the unit holds bottom very well as deep as I have been - about 140 feet so far - and seems to mark fish and bait well in automatic mode. That said, this is the only fish finder I've ever used. Overall I like the unit for my purposes. Obviously I'd prefer that they not ship a bad unit in the first place but stuff happens.

BTW, I bought the Standard Marine PS-1000 VHF and the LMS-334c sends it position data no problem. It also send the time but I think it is UTC time. Any idea how to change this to show local time? I suppose I should read one of the manuals (not to say I haven't)...

-- Bud

rumn8r posted 06-26-2006 06:46 PM ET (US)     Profile for rumn8r  Send Email to rumn8r     

Thanks for the info. I called Lowrance today but couldn't get through to a real person. You wrote:

The 200 kHz element in this transducer has a cone angle of 20 degrees but it also has a secondary lobe that can provide upo to 60 degrees of coverage.

What is the deal with the secondary lobe? I did manage to find someone very knowledgeable about these units (at Jays Sporting Goods, Clare MI) and he said that the 200 khz transducer on the single frequency unit can "see" a downrigger weight up to about 3 mph. If the secondary lobe is 60°, then that is more than the 50 khz transducer and should see the weight all the time.

For what its worth, he recommended the internal antenna over the external although he didn't have any internal antenna models in stock.


rumn8r posted 06-27-2006 09:37 PM ET (US)     Profile for rumn8r  Send Email to rumn8r     
Has anyone with a 337 or 339 tried it with the Lowrance single frequency transducer P/N 106-72 (HST-WSBL)? I got through to Lowrance today and was told that it would work and there would be the benefit of higher power (4000 vs. 2400 watts) for a modest extra cost of ~$60 and the ability to switch to the dual frequency transducer at some point in the future (if needed).

I'm still undecided about internal vs. external antennas. Has anyone had reception probelms with a 332 or 337 with external antennas?

davej14 posted 06-28-2006 04:03 PM ET (US)     Profile for davej14  Send Email to davej14     

I am beginning to wonder about Lowrance customer support. It seems that you get different answers to the same question depending upon who you are talking to.

Regarding the single frequency 200 kHz transducer, if you look up the specifications it says it has a cone angle of 20 degrees. The marketing points printed on the box say "fish identification area up to 60 degrees when using high sensitivity settings". This was explained to me by Lowrance as due to a "secondary lobe" on this transducer. Lowrance also said that the 200 kHz element of their dual frequency transducer has a cone angle of just 12 degrees and that is as good as it gets.

You pose an interesting question about using the single frequency transducer with the LMS339C to achieve higher power. I don't know why you would need this since the LMS332C is good up to 900 ft in fresh water. I also wonder if more power could actually degrade the system performance if it is not matched to the transducer properly. If you decide to try it let us know how it works out. I would recommend you get an approval in writing from Lowrance.

On the antenna lock issue, I have it on pretty good authority that some of the internal units are just problematic. Some work fine and some do not. There is no serial cutoff or date code that will predict their performance. I returned my internal unit without trying it for an external unit. Now if I can get some time this weekend I'll have it running and report on the results after the holiday.

wwbach posted 06-29-2006 03:24 AM ET (US)     Profile for wwbach  Send Email to wwbach     
As a point of reference, I seem to lose my downrigger balls at about 60' trolling at 2-3mph with the LMS-334c (Lake Michigan). -- Bud
rumn8r posted 06-29-2006 05:49 PM ET (US)     Profile for rumn8r  Send Email to rumn8r     

Changing the sensitivity increases the effective cone angle (at a loss of resolution). Can you change the sensitivity to see the downrigger weights at a faster speed? I don't think depth should matter.

PeteB88 posted 07-01-2006 02:26 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
I spotted on on sale - should I buy it? Bottom line - great price. Whaddaya think?
wwbach posted 07-10-2006 07:27 PM ET (US)     Profile for wwbach  Send Email to wwbach     
rumn8r, I think that the deeper the depth, the greater the blowback so they seem to get out of the cone. You can crank the sensitivity up and see them a a greater depth though. I've only been to 85' now and I was able to see the balls. The lower ball is more difficult to see but you can make it out.

Also, no drops in two weeks with the new unit except going under a low bridge just as the unit had acquired its initial position. It also seems to lose position immediately before it acquires a WAAS signal -- almost like it is switching modes. Rock steady after that. -- Bud

Marsh posted 07-10-2006 08:03 PM ET (US)     Profile for Marsh  Send Email to Marsh     
My Lowrance 334 holds on to my GPS position even with the bimini top raised. How does it do that?? Can the satellite signals shoot thru the canvas top? Must be, but it sure sound crazy to me.


davej14 posted 07-12-2006 12:58 AM ET (US)     Profile for davej14  Send Email to davej14     
After mounting my LMS332C with an external antenna I have come to the conclusion that the Lowrance antennas are just not very good. I originally intended to mount the "hockey puck" on the top of my console. In this position, the antenna could not establish a position with the Bimini down. By raising the antenna up to the top rail on the console I can lock in multiple satellites and get WAAS correction information. As soon as I lower it to the top of the console I lose position. The plastic windshield significantly attenuates the satellite signals. Putting up the Bimini makes no difference in either location so it must be pretty transparent to the sat signal frequency.

As an aside, the Lowrance NMEA2000 network works great to interface the sonar/gps unit to the antenna and a fuel flow sensor. It was also very easy to interface the NMEA 0183 port to my new Standard Horizon PS1000 VHF.

In a couple of days I will post some pics of the completed project.

bsmotril posted 07-12-2006 04:29 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
I've got the same external puck antenna mounted on about a 6 inch mast in the front port corner of the console top, right behind my LMX-20C. I have no problems locking onto signals, top up or top down, and WAAS works fine too. Maybe the key is getting it up a few inches so it gets a better picture of the horizon. Here's some pictures:


JMARTIN posted 07-12-2006 06:54 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
I figured an antenna to the "stars" should get a good shot at them. Here is a picture of where I mounted mine. I wanted a spot where nothing would cover it up and a spot where it would not get in the way. It still is in the way, sort of. Lowrance 337 CDF, takes a minute to lock on then she works great. It is on a little post do-hickey.


davej14 posted 07-14-2006 02:29 PM ET (US)     Profile for davej14  Send Email to davej14     
My installation is complete. Here are some pics:

1. Here is the finished console with the LMS332c mounted on a RAM mount. I really like this arrangement. I can easily adjust the angle for any sitting or standing position.

2. This view of the console front shows the GPS antenna mount I purchased from We$t Marine. It also shows that when mounting to anything higher than about 6 inches, you have an unsightly connector that is hard wired to the antenna. It would have been better if Lowrance put a connector on the base of the antenna rather than a pigtail. I tried the antenna inside the plastic windshield but it didn't work at all on top of the console and the signal was greatly reduced if it was below the horizontal grab rail. In the final position I can get a position fix with the Bimini up and the boat in the garage!

3. In a NMEA2000 network, devices attached to the network draw power at all times. Unless you provide a means to switch off the power you will drain your battery during idle periods. To accomplish this I purchased some miniature toggle switches and a small utility box from radio shack. There are two switches because I also needed one for the light I added to the inside of the console.

4. Here you can see where I mounted the switch box and the NMEA2000 connection for the Fuel Sensor and GPS antenna. You can also see how I mounted the PS1000 Standard Horizon black box VHF which is interfaced to the GPS.

Overall I am very pleased with the results.

JMARTIN posted 07-20-2006 01:13 PM ET (US)     Profile for JMARTIN  Send Email to JMARTIN     
The thread that will not die.

I originally posted that I had no troubles with my external hockey puck antenna, Lowrance 337 CDF. Well, I had a "GPS Module not responding" or something like that last time out and lost my GPS for about a couple of hours, then it came back. First time that has happened in 2 years. I was in familar water and had the chart so no big deal, but I had forgotten that I have a couple of other electronic devices that use the GPS.

I also found that I have become quite dependent on the GPS to mark rocks, shoals, kelp, and what depth of water I am about to enter. It was a good wake up call for me to not depend on it too much when I am in unfamilar territory. John

jimh posted 07-20-2006 09:06 PM ET (US)     Profile for jimh  Send Email to jimh     
At over 70 articles in this discussion, I think we need a summary. Is the LOWRANCE LMS-334C-iGPS a good buy or not?
davej14 posted 07-22-2006 12:55 PM ET (US)     Profile for davej14  Send Email to davej14     

Sorry to hear of your latest problem. I found that I also get the "GPS module not responding" message with my LMS 332 external antenna occasionally on start up. The first time it was disturbing but since I have the antenna installed on the NWEA bus, I found that by turning the power to the bus off and on the GPS module is reset and it works fine. I have not experienced a failure during operation which would be more serious. Obviously with an internal antenna there is not much you can do but return it to Lowrance with an appropriate message.


I would offer the following for your summary. I strongly recommend against the LMS334 or the LMS339 which have the internal GPS antenna. The internal Lowrance antennas are inadequate and will be a disappointment in most installations. I would recommend the LMS332 and the LMS 337 which have external antennas providing the antennas are mounted above the plastic windshield and surrounding hand rails.

baron2744 posted 07-14-2008 04:10 PM ET (US)     Profile for baron2744  Send Email to baron2744     
I have owned and operated a LMS-334C-iGPS for over 2 years. The resolution is fantastic and the features outstanding. Until last week I was ecstatic about the unit, but my last trip out I had a problem. The bay was very rough, and the unit began tripping off when I would hit any serious wave. The power was still on as evidenced by the backlit keys, but the screen would go blank. After all Lowrance's troubleshooting suggestions, I still have the problem. Sitting still, the unit stays on, but if I apply pressure to any part of the housing, it blanks out again. Lowrance wants $200 + shipping and 3 weeks to repair it. I am not sure I want to spend the money to repair it. Instead I am considering moving to a different unit, not necessarily a different brand. If you want more info, you can contact me directly at If you are not going to be in any rough water, the unit would probably be all you could ever ask from a GPS/Plotter. The only thing I cannot tell you is how the depthfinder works at displaying fish. I rarely am in water deeper than 7' while fishing, and primarily use the unit for GPS and depth while running in shallow bay areas. I should also mention [here the topic was changed to a discussion of the accuracy of global positioning systems. We are keenly interested in expert or well-informed opinions on the accuracy of global positioning systems, and we invite all experts or other well-informed persons to discuss the accuracy of global positioning systems in a separate discussion.--jimh] You might also check out the cost of the after market charts. They can be quite expensive.

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