Topic: 2nd Unit Advise?

[PAH]

I have a 14 foot aluminum boat with a 797c2 SI mounted close to the stern (tiller steering for the gas motor).  Transducer is on the transom.  I'd like to add a 2nd unit on the bow/trolling motor, but I have a couple concerns:

1) interference between the two units.  With only 14 between the transducers, I suspect I'll have some issues.  The 60 degree cones will intersect in about 12 feet of water, so that would happen a lot.  I'm OK with turning off the 60 degree/83Hz on the bow unit.  The 20 degree/200Hz cones don't intersect until about 40 feet of water, so I might be OK there.
2) synchronizing waypoints between units

I have 3 different ideas for how to do this, but am not sure which way to go:

A) The ultimate solution - add a 798ci HD SI to the bow and interlink the two units.  I'd run separate GPS receivers, so they are as close to the corresponding transducer to minimize differences between units, and I'd share my weather sense device through the interlink.  Unfortunately, my 797c2 SI is no longer listed as supported on the interlink page.  I asked Humminbird support about it, and they said these two units used different data formats and could not be sync'd with the interlink.  If this is true, this is seriously lame on Humminbird's part.  Anyone know if this is really true with the latest firmware?

B) Add a 798ci HD SI onthe bow, but don't interlink them.  Again separate GPS is preferred, but waypoints synchronization is an issue.  I don't mind if the weather sense is only on one unit.  Can the Humminbird PC application convert waypoint formats between these units?  Anyone have any success manually syncing waypoints via the PC app?

C) Add a mount and transducer at the bow, and interconnect the two mounts with a custom cable so they can both connect to the GP16 and the weather sense.  I'm not sure this will work with such a long cable stub going to the empty mount, but I can test this before buying the extra mount and transducer.  It has the downside of needing to move the unit back and forth while on the water depending on whether I'm fishing from the bow, or firing up the gas motor to head to another part of the lake.

I'd welcome any suggestions.

Thanks,
Pete

[FuzzyGrub]

A couple things to think about:

- Where will you be sitting while doing most of your SI searching?  That's where the slightly larger 798 screen should go.  The 798 should be your primary navigation unit if you plan to have lake maps.  ie only one SD slot on 797 to save waypoints and images to.

- Not sure if you have casting platform or not, but make sure you will utilize SI on the bow.   The screen will most likely be further away from your eyes and all the harder to view, add to the fact if you do frequent bow position changes/direction, it will smear the SI display.   You can estimate and test the viewing distance with your current unit. 

- The 798 will have internal gps, and will require a 2nd recever to place it directly over the transducer.   Given your style of boat, I would think we are only talking about 3' from ideal.  Make sure you need that level of accuracy, and at the minimum, could be a purchase that gets moved out to future.

Anyway, a couple of things to be thinking about.

[Humminbird_Greg]

Good points FuzzyGrub.  I’ll try and answer his questions and ideas:

1.) Sonar-to-sonar interference is not that easy.  First off: the quoted transducer beams were measured in a laboratory environment and may not reflect the actual transducer beam width or pattern you experience in real life (which can change as environmental factors change).  That 60 degree sonar beam which is about 1 foot wide for ever foot of water depth reflects off of the bottom at that same angle (I am assuming a perfectly flat lake bottom as well as the transducer being mounted parallel to the water surface here) and so when in 12 feet of water the beam is about 24 feet across when it makes it back to the surface of the water.  Also, the sonar beam may not stop there but have enough energy left to reflect back down to the bottom and back to the surface of the water several times…  Same thing happens with the 20 degree 200kHz beam as well.  There are a lot of factors that can increase or decrease the likelihood of getting sonar-to-sonar interference and most of these are out of your control.  If you do get sonar-to-sonar interference you could try turning on and up the Noise Filter menu.

2.) Waypoint synchronizing: if you want this to be done instantly/automatically than the InterLink is the only way to go.  Your 797c2 Si unit can use the InterLink.  I wonder if the person you spoke with got this confused with the Ethernet linking of the 797c2 unit which it cannot do.  Just make sure that you update the software in your 797c2 Si unit (and new 798 unit) before connecting it to the Interlink or your WeatherSense accessory.

If you do not need instant/automatic waypoint sharing than you can save some money by using an SD memory card between both units.  You do not need a computer or the HumminbirdPC program for this.


A.) You will not need a GPS Receiver for the 798ci HD Si unit as it has its own built-in GPS Receiver unless you need to do as FuzzyGrub stated.  Read my comments about the 797c2 Si and InterLink above.

B.) You only need an SD memory card to keep the same waypoints on each unit as stated above.

C.) No custom cable is needed to share the GPS Receiver between two mounts.  Just buy the AS-SysLink cable.  You will still need the unit mount, power cable and transducer though (MS-M, PC-11 and XTM-9-Si-180-T).

[PAH]

@FuzzyGrub - Thanks, those are good points.  I'll keep them in mind and fine tune my plans.

@Humminbird_Greg - Thank you.  If the interlink really does work with between the 797c2 SI and the 798ci HD SI (latest firmware in both), then I'm sold.  The support email that concerned me was:

--- start of paste --------------------------
Dear Mr. Hawkins,

Thank you for contacting Humminbird. We appreciate your support of our products. Please note it is not recommended to use the 797c2 SI with the Interlink accessory with the newer models since the software is conflicting
between the two systems.

If we can assist you further on this subject or any other Humminbird related questions please feel free email us again or contact our Customer Resource Center at 1-800-633-1468 to speak with a Customer Service
Representative. Our hours are Monday thru Friday 8:00 a.m. to 4:30 p.m. and Wednesday 8:30 a.m. to 4:30 p.m.

Good Boating and Fishing!
Jennifer-CRC

--- end of paste ------------

I interpreted "the software is conflicting between the two systems" to mean they won;t work together.  Can you please confirm whether or not there is a conflict between them when interlinked?

Thanks again,
Pete

[Humminbird_Greg]

Pete,
When did you get this message?
At one time there was no software for some of the units that would allow them to work with the InterLink with the newer units.  We now have software for some of them - like the 797 units.  Let me know when you received that response and I will check up on it.

[PAH]

Thanks Greg.  I got that response on May 4th, this year.

Pete

[Humminbird_Greg]

Pete,
I spoke with Jennifer this morning.  This may have been as I thought: a hold over from when we did not have software for the 797c2 units that would support the InterLink and a newer unit.  I will caution you though that we still have some folks who have InterLink connection issues between units but most do not.

[PAH]

Greg - Thank you so much for looking into this.  I'm going to go ahead and get the 798ci HD SI and an interlink.  I'll probably start with the 798 at the bow and the 797 at the stern, since I spend most of my time at the bow, but it should be easy enough to swap them if I change my mind, given they use the same transducer.

Thanks again.

[George]

Hi Pete

I have a 16 ft aluminum boat with an 1197 unit.  My HB unit is in the center of the boat, I can see it will running the gas motor and I swing it forward to see it when running my trolling motor.  I have the SI transducer on the stern and a QuadraBeam transducer on my trolling motor (reinstalled it today), using a switch to go between the 2 transducers.

I should state that my boat originally had 5 seats which I converted to two casting decks and made a plywood console and installed a steering system.  I have used this boat for appx, 10 years and it works great.

George

[sonar2000]

George, we need pictures of this.  Really......it would be nice to see your setup...
Chuck