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mast repeater speed


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#1 Mike P

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Posted 15 May 2014 - 06:31 PM

I am looking for a simpel repeater ro stand alone instrument that will give my crew SOG.  

It seems to me the most simple solution is a GPS that displays speed with nice big numbers, runs on solar power or batteries and attaches to mast with Velcro straps.

I don't need start line pinging or heading or tacking info, just speed so my crew can see if they are making a difference when they trim sails and I can pay attention to heading and avoiding other boats.
Is there really nothing out there that is this simple???
Maybe I can make some money if a build and market one myself???smiley2.gif


#2 allen

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Posted 15 May 2014 - 06:59 PM

Sounds like a Garmin 152H.  It has many modes for the display one of which is a single display with huge letters.  It is discontinued but I see several on ebay.

 

Of course, many of the gps based boxes like the Rock Box Blue will do that as well and they have mast mount brackets available.  Some of these used Garmins look to be a little more pricy that I would expect so the marine boxes might not be that bad price wise.  Personally, I would try getting a used 152H at a reasonable price.

 

http://www.ebay.com/...cat=0&_from=R40



#3 Reht

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Posted 15 May 2014 - 08:36 PM

Thing is that the hardware in those (the GPS in particular) is pretty expensive. Unfortunately the average consumer wants to see more practical features which are mostly just different interpretations of the data. The average consumer would want to pay a small fraction for a device as you describe compared to the Velocitek stuff, but the bulk of the per-unit cost (the hardware) is the same for both units, thus the demand at a price-point where they could be manufactured is not really a viable source of income.

 

Get a second-hand something and you'll save a reasonable amount. When you have a box that has all the features you'll try them out and probably find that you really like them...



#4 Mike P

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Posted 20 May 2014 - 03:57 PM

Yay that's what I thought but no harm in asking for the collective wisdom

Thanks guess I will buy a Velocitek or Rockbox or ?????



#5 TheOffice

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Posted 20 May 2014 - 04:59 PM

a smartphone with iRegatta and a rockmount bracket and a waterproof case.  Run  a charging cable to it.

 

Cheap, effective



#6 allen

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Posted 20 May 2014 - 06:15 PM

If you want a smartphone application for racing mine is better :-)  It's free if you qualify.  I don't sell it.  If you want an app for playing around or cursing, iRegatta is better.  I didn't mention it because the op said they wanted only SOG and no starting so the Garmin 152H would be perfect.  I don't know why he dismissed it as a solution as it does exactly what he asked for.  But for a total race solution with starting, waypoints, calculations of AWA for the various legs in the race, compensation for current, I have StartLine4.  It is not simple however.  But in racing, it does all the switching of waypoints automatically and calls out the layline.  You never have to touch it during the race, only in the pre-start.

 

Allen

L-36.com



#7 Schnick

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Posted 20 May 2014 - 06:23 PM

If you just want SOG get an old unused iPhone or Android, stick it to the mast, connect a cable, or don't and just charge it between races.  There are many many 'speedometer' apps out there for free that will read in knots.  Easy Peasy.



#8 Mike P

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Posted 21 May 2014 - 07:02 PM

O.K. I am lazy and I don't want to run 12 v power up the mast that is why I asked about solar powered or battery.



#9 Moonduster

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Posted 22 May 2014 - 05:21 AM

Reht,

 

What do you mean when you say expensive? A GPS/GNSS receiver is less than $10 in quantity 1000. In volume, I'd guess less than $3.



#10 Reht

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Posted 22 May 2014 - 02:04 PM

Those are the cheaper variety. It's when you're looking into the high-accuracy units (the ones that will have your location to within a few inches rather than a few meters) get expensive. I guess for most applications the lower accuracy ones (which are as cheap as you mentioned) will do, but many of the higher-end (ie not just generic GPS devices) products need that accuracy...



#11 allen

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Posted 22 May 2014 - 02:56 PM

I am aware different levels of GPS accuracy.  Normal GPS accuracy is quoted at the 50% confidence level.  That means if you use the number displayed on your GPS, you will be within that half the time. 

 

Systems that get inches of accuracy are using external data either from another radio or off the web.  I am not aware of any marine systems that would be more accurate than a WAAS GPS.  

 

My measurements, which are more or less worst case error in an hour, show WAAS level GPS error between two measurements (like a boat and a starting line that was pinged) to be about 30 feet or 10 meters.  A phone GPS would be about twice that.

 

But the op wants speed and that cannot be augmented except by averaging several runs which is not relevant here.  Speed seems to be within a few tenths of a knot.

 

If anyone knows of systems for marine use that would be more accurate I would love to know about it.



#12 TheOffice

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Posted 22 May 2014 - 04:43 PM

Allen,

 

is StartLine available for iOS?



#13 allen

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Posted 22 May 2014 - 04:56 PM

^^ StartLine is Android only.  Sorry.  It will run on an old phone or any Android tablet.  The phones I have used to not need to have sim cards so they are really just small tablets. 



#14 allen

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Posted 22 May 2014 - 07:27 PM

@TheOffice

 

Here is a sample of the check screen readout after my last race. 

 

temp.png



#15 Velocitek

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Posted 22 May 2014 - 08:11 PM

@Mike P - It sounds like the Velocitek SpeedPuck with a Mast Bracket is exactly what you're looking for!






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