Is there any advantage to being farther ahead or back when mounting dual antenna’s? Otherwise from what I have read the advice would be as wide as possible on top of the cab, correct?
I believe you enter dimensions in program and it will calculate what is needed. I think there is relation between hight from ground and width between antennas. Tractors are not that tall so that 10…20 cm affect anything. Did you see you have to use reflecting metal plates under antenna? That will limit how wide you can have it on tractors roof.
Without imu it won’t know if your front wheels are in low or high ground so there will be rounding errors anyway. You would need 3 antennas to measure 2 axis.
My kit is in shipment but I think I’ll place near roofs back so it would be closer to rear axle. Placing in front will smooth out rough terrain better. You need to experiment to find best place. Maybe front is more clean from dust too. Also take into account tree branches you may encounter.
Thanks for taking the time to respond. I put together my dual antenna set up a few weeks ago. It is working really good. I made a bar to go across at the cab lifting bolts. I used survey antennas, so I did not need ground planes. I have been very happy with it. Single IMU is good, but dual still has that little performance edge.
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How much is it over edge? I would be afraid to knock them down when mowing near trees. I would also add rubber strip between two metals. You will scratch roof paint and another thing it will start to rattle after some time.
Did you try with those small black antennas? I ordered kit with those small antennas. Wondering how big difference it is. Two large antennas are quite expensive if sum up. Are they very big? I somehow like idea them to be flushed into roof. Lower part isn’t actually very functional. I don’t need neighbours to see “big business here”
Found interesting point in another thread
Brian Tee, [07.11.19 01:33]
There are 2 errors for guidance. A heading error and a disctance error. Putting the antenna right over the pivot point really limits the feedback for distance off the line since as the tractor turns, the distance takes a long time to change as the tractor turns toward the line, and will tend to overshoot the line. So it is a balance between moving the antenna farther ahead for distance and the errors associated with heading.
The antennas are about even with the edge of the cab. Yes, they would be more prone to snag on trees, but we keep our field edges trimmed up and occasionally when I do custom work I go around trees on field edges. I am not going to risk ripping off mirrors, lights, or GPS antennas to plant some corn in the shade under the tree.
In my experience the white antennas perform slightly better than the black patch antennas. This spring I had a field drive that had a couple tree branches hanging over the edge. I drove the sprayer in which had the white survey antenna. It never lost RTK fix. An hour later I went through with the tractor which had the patch antenna before I installed dual survey antennas. It lost RTK fix for a few seconds. The difference in performance is very small. I used the patch antenna for a long time with great success.
The bar is mounted with spacers, so it does not contact the roof panel or rattle.
(The picture in the first post was automatically cropped, so it cut the ends of the picture off)
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I’m reading people get better results by placing antenna in front part of roof.