Installed a calc-an-acre II in the XR 3140

   / Installed a calc-an-acre II in the XR 3140 #1  

spruce Deere

Veteran Member
Feb 1, 2009
Northmost Idaho
John Deere 790 with loader LS xr3140h also with loader plus a cab
After using a not so accurate, frustratingly slow to get a signal off-the-shelf GPS speedo unit, I upgraded to a calc-an-acre II satellite unit.

Calc-an-acre is a device used widely in the ag industry for accurately measuring acres worked, speed, application rates being applied and other stuffs. You program you width of implement, it figgers out the rest.

The calc-a-acre can work off satellite signal or magnet sensors system mounted on tire rims for calculating everything it can do.

Magnet system is cheaper but has more wires to figger out were and how to run. The disadvantage to this cheaper system is if a tire is sliding or spinning, it throws everything off, or mud and other obstacles interfere with the magnetic reading.

Anyhow, chose the sat unit for a more simple install, less wires to fuss with. It is quick to aquire signal, even under a canopy of tree limbs and reads down a 10th of a mph.

Mounted the satellite 'puck' with a piece of strap metal welded to the light bracket for a completely clear view of the sky and used a round magnet to mount the calc-an-acre unit to the metal cross bar between the dash and right hand door.


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   / Installed a calc-an-acre II in the XR 3140 #2  
Interesting, What will u be planting ?
   / Installed a calc-an-acre II in the XR 3140
  • Thread Starter
We will be planting mostly blue spruce. Being able to know and keep constant speed greatly helps keep trees you are planting in consistent, even spacing... That was to slow for the first Speedo we tried.
We mark out the field with rows, but having a constant speed the transplanter operator likes 'the wife' GREATLY helps keep rows nice and even with each other. The calc an acre will be very helpful with that.
   / Installed a calc-an-acre II in the XR 3140 #4  
It would be good for spraying for fire ants I bet.
   / Installed a calc-an-acre II in the XR 3140
  • Thread Starter
Thankfully, there is no fire ants here... Plenty of other nuisance, crop destroying insects to deal with though.

Spraying for insects in the tree fields is where the calc an acre helps the most though. I can enter how wide of swath I am covering and it will tell me the acreage I cover and how long it took too do.

In doing custom tractor work, I will be able to tell how many acres I worked, not what the standard surveyed acerage figgers. Lots of long hills and deep draws here and you can figger actual acreage worked with the calc an acre....It would be like flattening out every square foot of all the hills and draws for a more accurate acreage count.
   / Installed a calc-an-acre II in the XR 3140 #6  
Nice addition. Sounds like it is going to work well for you and your planter spacing.