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Australia | Mike,
I agree Rick (crh) has been doing a great job answering mojoRTK questions on this forum for those interested in mojoRTK. I would like to clear up one thing that looks to be getting some incorrect press in the forums regarding the RTK correction options mojoRTK supports... to build on what Rick has said. This is a complicated area so here goes.
1) mojoRTK base in portable mode (available online or via resellers)
A simple option for operating close to the field. Can run multiple machines off the base but 900Mhz range issues come into play as the antenna is only at ground level. Good for contractors or smaller operations. Again, as soon as you start running more than one machine, the subscription services begin to get expensive in comparison to owning your own RTK base station.
2) mojoRTK base in fixed mode (available via resellers)
You can buy a mojoRTK base and separate the antenna from the bottom housing (6 screws). You then mount the bottom in your workshop or in an outdoor enclosure of some type and hook it up to mains power (or solar). The GPS antenna gets mounted outside in clear sky; the 900Mhz whip antenna goes up a mast, a roof, or grain elevator. The internal batteries now become battery backup for the mains supply giving you 8 hrs if you lose mains power.
If you want to have a mojoRTK in many machines then this is a very economical option and a high 900mhz antenna can give you huge range. It beats paying a subscription for each machine. A 16 mile radius covers, in theory, 1/2 million acres but radio repeaters (as Rick said $500 a piece from Maxstream) may be needed to take advantage of this coverage. mojoRTK baseline range upgrades will be needed as well.
3) mojoRTK in Simple Network mode (released via resellers)
You can buy a mojoRTK console unit alone ($6,990) and upgrade it ($2,990) to receive CMR or RTCM corrections from many of the simple RTK networks being installed by precision ag dealers around the country. This option is mildly complicated as you will need your local reseller to configure the Trimble, or Freewave radio to plug into the back of the mojoRTK unit using RS232. CMR or RTCM is a standard so this should not be too difficult for a reseller who knows their stuff. The advantage here is that the mojoRTK base station is not needed which saves $5,990. The individual private network fees vary a lot around the country ($800 - $2000 yr) as do the external radio costs (some up to $3500 a piece!) so look at the economics first, particularly if you need to autosteer more than one vehicle.
4) mojoRTK in CORS Network mode (not released)
As discussed in these forums, there are many state run CORS RTK networks operating or under construction. Leica and Trimble build these networks mainly for DOT's. The mojoRTK has a built in CDMA modem we use for Virtual Wrench when service is needed, but when its not, we can use it to connect to a CORS network (Trimble or Leica). If your local network is free to connect to, then all you will need is a CDMA dataplan from Leica (via Aeris) to access the network. In this mode the mojoRTK does not need a base station so the price to $6,990 plus CMR or RTCM upgrade for each tractor unit. This option will be cost effective for those who can take advantage of the DOT infrastructure. Coverage of the CORS network, dataplan costs, and CDMA coverage issues will influence your decision here.
I hope this clears up the misconception that mojoRTK can only use a portable base station. There are many options with varying costs which most serious GPS companies support; you just have to do the math for your farm to get the right solution for you.
Regards
John
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Thank you guys
