GPS Repeaters

[reeac]

Our Garmin GPS 128 has a nice "compass-style" display which enables you to sail towards a waypoint but it's at the chart table. We'd like to have a repeater above the companionway but all the repeaters that we've seen have what I can only describe as "inverted setting sun" or shallow road style displays which are nothing like as clear. Does anyone know of a GPS repeater that gives a compass style display?
Reeac.

<hr width=100% size=1>

 

[Moose]

Another Garmin 126 or 128???
The handheld Garmin 12 does (in fact its operation is identical to the 128 and 126 except its smaller)


<hr width=100% size=1>

L' Moose

 

[pvb]

Just a thought...

Why not put the Garmin 128 in the cockpit and have a repeater at the chart table?

<hr width=100% size=1>

 

[Rich_F]

I'd second Moose's suggestion of getting a GPS12 to use in the cockpit - that's what we do.

Also, I'd recommend looking into using the rolling road display. It isn't as obvious when you first use it, but in my experience is far more useful than the compass display once you've spent some time with it.

Rich

<hr width=100% size=1>

 

[roger]

I like having the GPS below decks. Its much easier to input routes and waypoints with the chart nice and dry.
We use a Navman repeater. Its vestigial in the rolling road department but very handy for letting you know how long you have to go etc. It also gives you system voltage which is very useful.
The most useful thing about a repeater is that it tells you when to change course (reached a way point - make for the next). It can be a real pain having to sentd someone down below to tell you when to turn.
If you are fitting to a bulkhead or similar, do check on the hole you need. Some instruments need a very large one which will take a lot of filling up when you change - as you will after a few years.

<hr width=100% size=1>Roger

 

[milltech]

Do you not think that the addition of a second GPS doubles the potential for data input problems, and if not charting from the same instrument as steering the situation might go unnoticed for a dangerous period of time?

Speaking as one who once tried to sail to the Val de something-or-other mark about 7 miles off Normandy but actually had entered the Point de something-or-other on shore.

<hr width=100% size=1>John
<A target="_blank" HREF=http://www.allgadgets.co.uk>http://www.allgadgets.co.uk</A>

 

[Rich_F]

Good point, about problems of having dual GPSs. To answer the point directly, though, I think that having 2 GPSs could be a positive help. If the GPS controlling the steering is different from that doing the charting, then you will probably notice from the charting GPS if they are not in sync, because the boat will be steering away from the programmed track.

However, I enter my waypoints, etc via a PC, and I can switch the output of that PC to either the fixed GPS128, or a cable that plugs into the handheld GPS12. So my route planning involves programming the PC, then dumping the same information to both GPSs.

A non-PC alternative would be to program one GPS, then dump the waypoints and routes to the other.

On my boat, the fixed GPS provides me with NMEA data for the PC and (occasionally) autohelm, and a repeater next to the VHF for maydays, etc. The handheld is my main GPS; I often don't bother dumping waypoints on the fixed GPS unless I plan on using the autohelm for waypoint navigation. (Normally I just use the autohelm to maintain a course, so NMEA input is unnecessary).

Finally, a useful tip. If you use a PC application like Oziexplorer, it is possible to input your own track on the PC. If you use this facility to create a track by "tracing" round your local coastline, you can then dump that coastline to the GPS, making it into a simple plotter. That at least makes it clear when you're sailing for a landlocked waypoint. I'd be happy to suply rough-and-ready Oziexplorer track files for the Solent or Clyde coastlines to anyone that's interested.

Rich

<hr width=100% size=1>

 

[circumnavigation]

Hi:

We have the 128 at the Nav Station, using a NASA repeater. The repeater is, as all will know, a device to repeat all the information you wish to know, thus sitting in the cockpit, but not compass style.

We also have the Garmin 12 and 48 as back-ups, with compass and rolling road sreens, which is all they are; back ups when the 128 goes down, which, as yet, has never failed. For what I believe you are requesting, the NASA Repeater will be ideal for you.

I would say, vehemently, that many contributors to this Forum in general, are not global navigators and some of the advice given is dangerous, especially given to those starting out with boats are really would like genuine information. Take the advice given absolutely, but check it out with professional expertise if not totally understood.

Good luck

<hr width=100% size=1>http://www.mpcee.co.uk/katoema.html

 

[BrendanS]

I'm starting to become quite troubled about the idea of repeaters up top, when the actual system is down below.

Do you know how your systems hands off a new leg, ie when it thinks you've reached a waypoint, and transfers you to a new leg/

Is your system using a bisect between legs along the waypoint, or proximity to waypoint. I know how mine works, but it seems many don't

<hr width=100% size=1>

 

[circumnavigation]

Hello:

I am from the old school and every aspect of my navigation IS manual. However, Katoema was completey refitted for her circumnavigation. With a 3/4 covered doghouse, offering protection from the forward and side elements, there are now backups to the vast array of electronics and communication equipment to verify what is happening around her. Without going too deeply into the equipment that I have on her, because of my profession, some of which will only be found on certain types of vessels under the IMO. Consequently and not being indifferent, I refer to the repeater as it is available commercially and, in essence, should be checked against the paper or electronic ARCS charts. Other commercially available electronic charts are suspect, as paper charts can be through Chart Datum differences when used with electronic equipment, especially GPS.

<hr width=100% size=1>http://www.mpcee.co.uk/katoema.html

 

[pvb]

Well, that\'s cleared that up, then!

Or not.

<hr width=100% size=1>

 

[BrendanS]

So, does your primary system use bisection, 90 degrees or proximity? and what does your secondary system use

did you even understand my first question

<hr width=100% size=1>

 

[Strathglass]

I have a 2nd hand 128, and have just purchased ( from John at All Gadgets) a NASA repeater and also an XM DSC VHF.

I was really pleased when, connecting them all together (without refering to the GPS handbook) on the kitchen table that they all immediately comunicated with each other.

The repeater displayed the GPS info and the VHF showed the time as well as the position.

My intention is to use the GPS internally at the chart table (at the foot of the companionway steps). The VHF near the hatch, accessable both from the chart table and the cockpit. Then the GPS repeater in the cockpit as a secondary aid to navigation, probably mainly using the rolling road.

Everything is a compromise, especially on a boat, just decide what will best suit your own style of sailing.

Iain

<hr width=100% size=1>

 

[reeac]

Thanks, everone for your replies to my query. It does seem, however, that there is no repeater available which gives a compass-style display which we feel is by far the clearest type when sailing to a waypoint. I fitted an MLR GPS to our previous boat - chose it because it was the only one with an proper alpha-numeric keypad which makes life so much easier. It had a compass-style display which I recall as being clearer than that of the Garmin. We may buy another MLR if it can be installed above the companion way but it would have been preferable to keep the main GPS down below in the dry and have only a repeater out in the cockpit.

<hr width=100% size=1>

 

[circumnavigation]

Hello Brendan:

Sorry for the delay in getting back to you. I do not use any of the electronics on board for taking precedence in making decisions like making course changes etc. They are an aid to mental calculations, when taking into account what is happening around me by way of the elements affecting my vessel's known characteristics. The challenge is making those calculations, without electronic assistance, then checking one against the other.

How a piece of electronic apparatus applies its own logic when deciding a course change at a waypoint is of no real concern to me, but it should to someone that relies heavily on electronic navigation. In a fast moving race environment, the navigator/statistician may well need to know how a piece of equipment calculates what is required, to have that leading edge, but I am travelling at a pace that is conducive to my requirements, knowing that with a draft of 2 metres and a long keel, it will always be necessary to use electronic waypoints with caution.

On a personal note, as a onetime professional navigator in the 60's and early 70's, I originally took my Yachtmaster Offshore in the early 80s, but resat it 20 months ago to be up to date with electronic navigational aids. It is still a case that I continue sailing by eyeball and manually plot on UKHO standard charts, but as I say, the electronics are there and used in harmony with traditional methods.

The debate was about GPS Repeaters and I chose the NASA for my particular requirements and it sits there, along with an array of instruments, bone dry in the doghouse next to my own calculations and appropriate chart.

Martin

<hr width=100% size=1>http://www.mpcee.co.uk/katoema.html

 

[BrendanS]

Martin,

Given your original comment:

>>I would say, vehemently, that many contributors to this Forum in general, are not global navigators and some of the advice given is dangerous, especially given to those starting out with boats are really would like genuine information. Take the advice given absolutely, but check it out with professional expertise if not totally understood.<<

Given your comments on your background and experience, I'm rather disappointed that you are still hedging, and obviously don't know how your own systems work.

I take your points about manual working, and keeping everything plotted on a paper chart (though your own posts suggest you have quite a heavy backup of electronic aids) , and I totally agree, but my original point was about having GPS repeaters up top and people relying on them, if they are handing you off to a new leg without people understanding that they could be 20nm off the waypoint, they could be setting a new course across a headland or rocks.

<hr width=100% size=1>

 

[circumnavigation]

Brendan:

See PM

Martin

<hr width=100% size=1><<http://www.mpcee.co.uk/katoema.html>>

 

[webcraft]

Compass display vs highway

The bearing to a waypoint is not the critical piece of information to watch when using GPS waypoints as your primary navigaton tool. You should be more concerned with the cross track error (XTE on most GPS displays).

If making leeway due to wind or tide the bearing to your waypoint will obviously change. If you merely steer the new course as shown by the bearing to the waypoint displayed on the GPS then you do not necessarily know if you are off your planned track, and your new track could easily take you over dangers that now lie between you and your waypoint.

The 'highway' display on a GPS shows whether or not you have strayed from your intended track, by how much you are off it and which direction you need to head in to get back on tack and so into safe water. It is virtually foolproof assuming that the waypoint has been put in correctly and IMHO is infinitely preferable as a steering device to the compass display.

Please accept my apologies if I am stating the obvious . . . I just find it hard to understand why anyone would prefer the Compass display to the Highway screen available on most GPS sets and repeaters.

- Nick




<hr width=100% size=1><font size=1><A target="_blank" HREF=http://www.bluemoment.com>http://www.bluemoment.com</A></font size=1>

 

[paulplatts]

Re: GPS Repeaters - alternaive

You could consider an ICS Navtex 6+. Might seem a bit of an odd choice at first, bit I use this with my GPS Garmin 128. Works well as a GPS & instrument repeater as well as the obvious dual frequency Navtex.

So you get all of this extra capability as well as a larger display repeater than most other repeaters.

Please note I have no connection with ICS, but I am a satisfied owner.

<hr width=100% size=1>

 

[Oldhand]

Re: Compass display vs highway

Are you suggesting that when crossing the English Channel navigators should keep cross track error minimal? If so, those of us who only use XTE as an input for a mental curve fitting exercise on such a voyage will arrive at the destination long before you, given the same speed through the water.

There are numerous inputs required for efficient navigation, i.e. ship's heading, COG, ship's speed, SOG, bearing to waypoint, distance to waypoint, set & drift and leeway. A graphical display is only any use in constant conditions, i.e. when none of the above inputs are changing significantly. What is very useful in changing conditions is noting the curve of the track already covered and then predicting what its going to do for the remainder of the leg.

<hr width=100% size=1>