Topic: GPS problem

[crazy cranker]

Over the past 18 months Humminbird has sent me (5) replacement units (788ciHdDICombo) due to various issues.  All of the units have utilized the internal antenna.  On the 5 local reservoirs that I fish the 1st and 2nd unit would acquire sufficient satellite fix within 1 to 2 minutes.  The forth unit could not get a satellite fix at all.  The 5th and current unit which was actually water tested by Humminbird before it was sent (supposedly) takes 15 to 30 minutes to acquire a sufficient fix.  All of the units were mounted on the driver dash on a Ranger Z118 in the same manner.  I have the Humminbird external antenna but I have read that it probably won't help the acquisition time so before I go to the trouble to mount and connect it I need an expert opinion as to if it will help.  Additionally, has Humminbird changed something in the receiver circuit of their head units or done some software update that may be causing this problem.  I have read posts from other guys that complain that they have to turn their unit on when they leave for the lake or they have the same acquisition time problem.  Doug Vanderberg claims that the Humminbird circuitry is superior to other brands but they Lowrence guys don't seem to ever post problems about satellite acquisition.  Any help would be appreciated.

[werethefugowee]

My 997 loads up in about 1 to 2 min. - everytime. Never a problem.

[ITGEEK]

My 2 cents is that I would never use an internal antennae if an external
will work with my unit.

It's possible that something is blocking the unit/internal antennae.
The human body (you), can block GPS signals, depending on where you
are, and the angle of the satellites.

I would mount the external antennae and go from there.

[4d-rock]

Are you always using it on those same local reservoirs?  And are they generally in the same area?  Or have you tried the units anywhere else (maybe another state)?
I'm just wondering if it may be the location that is not ideal for satellite reception, rather than the units themselves.  Even on our expensive GPS units ($5k each) we use at work can take a while to get full satellites if the conditions aren't the best (eg. heavily treed area, thick overcast, in a valley or somewhere where land blocks a good portion of the sky).

Just throwing another idea out there that's all.

[crazy cranker]

Same waters, same launch sites.  We even tested it against a hand held Garmin Etrex.  The hand held acquired the satellites with no problem.

[ITGEEK]

Have you thoroughly tested your power supply and
connections?
A bad/borderline battery will cause all kinds of problems.
Charge up your battery and load test it.
Check for tight connections and a good clean fuse
and holder.

I'll bet many an unhappy customer has sent a unit
back to Humminbird, thinking there was something wrong
with the unit, when the battery was the culprit all along.

[crazy cranker]

The main battery to which the locator is connected and the trolling motor batteries were recently tested with a $3k carbon pile tester.  As you may or may not know a carbon pile tester is the only accurate way to test the condition of batteries under load.  The $100 junk testers like those used at Auto Zone do not apply a load and cannot accurately measure condition under load. 

As it relates to the connections, they were cleaned and coated with NO-OX-ID "A-SPECIAL" which is the electrical contact grease of for new electrical installations and maintenance. NO-OX-ID is an electrically conductive grease that keeps metals free from rust and corrosion. This electrically conductive grease which has been used in the power industry for over 65 years to prevent corrosion in electrical connectors from low micro-power electronics to high voltage switchgear. NO-OX-ID electrical grease prevents the formation of oxides, sulfides and other corrosion deposits on copper, aluminum, lead and steel surfaces and conductors.

Clearly there is an issue with Humminbird's circuitry.  These issues seemed to crop up when the units were updated to contain the NMEA related visuals.

[Humminbird_Greg]

Welcome to the Humminbird Side Imaging Forums crazy cranker.

It’s hard to believe that you would have gotten three out of five units all with the same GPS problem but I guess that it could be statistically possible.  There has been changes to the GPS Receivers we have used over the years but I have no way of knowing if these changes were made on any of the units that you have had or have now.  The units should be able to acquire a GPS Fix in under a minute if they do not have to go through a cold start.  Even than 15 to 30 minutes is too long.  I would try testing your current 788ci HD DI Combo unit at your house to see if it works any faster/better.  Next I would try connecting up the external GPS Receiver and just placing it where you are thinking about mounting it to test it to see how well it works.

[crazy cranker]

Greg,

Thanks for your reply.  I'll try your suggestions.  When I received the last unit, that purportedly was tested on the water in Eufaula, I checked it in my driveway and it appeared to go through an initial start-up.  If the unit had been actually tested in Eufaula would it go through another initial start-up due to the change in geography (Alabama vs Arizona)?   

Actually only the last two of the five units exhibited the GPS satellite acquisition issue.  I'm sure Sharron Bates has a record of the serial numbers for the five units - is there any way to ascertain if the circuit change that you mentioned was related to the last two units?  Based on posts from other customers who have experienced the same problem it may be good if Huminbird could determined if their changes have negatively impacted satellite acquisition so a fix can be implemented.

[Humminbird_Greg]

Yes it would crazy cranker.  I think the rule is if the unit is more than 200 miles from the last position that it had a position fix at or if it has been more than 2 months since the last time it has a position fix; it will go through what is called a “cold start”.

Without seeing what the Techs found wrong with the last two units there is no way of knowing whether any changes made in the GPS Receiver or software have affected the satellite tracking or acquisition time.  Humminbird keeps pretty good track of the complaint and repair fixes for all of the units sent into us and review these on a regular basis to look for trends or new problems so that the Engineers can start working on any that are found.  So if there is a problem with the GPS Receiver or the software we should detect that and start working on a fix.

[crazy cranker]

Should I contact Sharron Bates to find out if anything was determined on unit #4 that was returned?  It sounds that based upon the variables (distance and time between uses) that the unit may have just been going through initializing each time.

[Humminbird_Greg]

I’m not sure that they can find out what was wrong with that unit cc.  Since it was replaced they may have destroyed it.

[crazy cranker]

Is there some way that the unpowered time duration that activates the initization mode can be re-programed to expand the time limit?  Possibly a re-program fix emailed that could be downloaded on a scan disc then loaded into the head unit.

[Humminbird_Greg]

I don’t know the answer to that but would guess not.  I’m guessing that this is preprogrammed into the GPS engine that we purchase.

[crazy cranker]

When I connect the AS-GRP antenna should I switch GPS Receiver Override setting from internal to external or automatic?

[Humminbird_Greg]

When you connect an external GPS Receiver the unit should automatically switch to using it.  You can make sure though by manually setting it to use the local external GPS Receiver.