I am trying to find a good place for the RS2 to be used as an NTRIP base. Roads are surrounded by buildings on both sides. We have access to a building where we can place the RS2 on the roof itself. The problem is the roof is made of steel sheets. Will this help or add to multipath errors?
Probably mostly add, as the roof will reflect more than absorb.
However, elevation over the roof will help a lot, the more the better, but you then have to mitigate the potentiel error from the mechanical component (pole that sway in the wind, temperature variations etc).
I know with other manufacturers, they recommend at least 10 feet above a metal roof to minimize multipath.
I put a base antenna on a roof at about 5m from ground level.
Even the Trimble base would only allow a max height of 4m to be entered, so i just entered the max.
How will this effect measurements of rovers from this base?
Since its used for guidance I have not noticed any problems as measurements are relative. But would it throw out measurements if used for survey?
Did you “survey” in the base with either post process or using NTRIP? Elevation shouldn’t hurt you for two reasons. First, everything you record is relative to your base as long as you are using the same base. If you “survey” with the permanent base and use another base and it has actual height, your elevation will be off. This would cause problems in my application where I am installing drainage tile or waterway ditches which elevation is extremely relevant. If you are just steering and or creating a topo map again everything is relevant to your base. Your elevation from Sea level is off by XX amount.
Second, antenna height if surveyed should be zero because when you survey it in you get the stated Lat/Lon/Alt. It doesn’t matter if it is on the ground or 10 meters up.
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Don’t bother with entering the height over ground. For a fixed installation, you will be able to pinpoint its location very well over say a 24-48h obs-time.
And if it is for relative measurement anyhow, then no problem at all.
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Thanks that makes a lot more sense.
Use it for guidance mostly. So just used the timed average position it came up with.
Did some field drainage with it too, but all measurements were relative to themselves and it worked. I am 2200’ feet above sea level, so drainage works really good if you find the right edge, Haha 
But always looking to get it dialled in even more.
If I am setting up a permanent base, most states have CORS network that I NTRIP to and let it average for about an hour. Since their base stations are surveyed in, mine basically are. Works well.
For most of our grade work, we only do a 5 minute average as the job is all relevant to that base LLH
I am from Alberta Canada, we pay twice to three times for everything.
The only two RTK corrections networks that are available in my area are Cannet run by Trimble, and CaseNewHolland also run by Trimble. You can see the competition is just massively effective. Just the cell modem they sell that is mandatory to access either network (its the same base) is worth more than an M2 by almost double. In Southern Alberta there is one dealer running their own private network and the costs are high but not insane.
Deere offers the buy it all yourself Navcom $30k RTK, or the cellular base 300km away from you package, or the double stack unlock fee of about $5000 to use MRTK. Mobile RTK allows using RTCM3.0 corrections with Navcom. There are a few Deere RTK stations run by a private company in Alberta.
Needless to say why i figured out how to run my own RTK. Hopefully I can Integrate EMLID into all my equipment to sidestep these brutal unlock fees for everything.
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My first guess would also be it will add to the number of multipaths.
But I wonder, if you’re using a separate antenna, wouldn’t it be possible to make a custom ground-plate with small border so that roof-reflected signals are always blocked, and that groundplate-border-reflections always come from sats with an elevation which is already filtered anyways?
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https://kb.igs.org/hc/en-us/articles/202094816-Monumentation-Recommendations
https://kb.igs.org/hc/en-us/articles/202014573-New-Site-Checklist
Appreciate the replies and links. Will read up on them. The reason why I wanted to place it on the roof is because of the ground plate comment. The entire roof could be used as a ground plate for the antenna. Am I making any sense? Just trying something new.
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I welded together a mount for my friends shop roof. It seems to work pretty good.
It mounts right on the front of the shop at the peak. Have not had multi path issues i know of. The roof is corrugated metal.
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You were able to get repeatable values for that point? That is similar to the steel roof that I plan to place my base.
The steel bracket is about 3x the diameter of the antenna.
It is used for ag guidance, and we have not had any problems running the equipment as tight as 1” overlap.
Ive also used this for ag 30km away without any issues either.
Unfortunately I am not a surveyor so I cant really give any good numbers for proof. But it has never made the tractor steer with any error larger than 1”
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The sloped and corrogated roof should help mitigate some of the multipath issues compared to a flat, smooth steel surface.
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We don’t seem to have any trouble either with this . At first we had a RS+ up there and now I got the M2 working day and night no problem. Its sitting on a pole 3 feet off the roof ridge
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How are you liking the M2’s Dave?
Awesome not waiting for fix, eh. 
I am currently in a Case combine trying to figure out what i have to do, to get Emlid to talk to it. Wheats dry enough a guy can get a little work done in the cab, lol.
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I use it for a permenant base only , Its perfect
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