Obviously the higher, the more distance error caused by angular error.
So far so good.
I usually say it depends a lot on your surroundings. There are some questions one could ask before placing the base:
- does 1-2 meters more elevation help me get a better signal?
- by extending the pole 1-2 meters, will the receiver start to sway so much that the increase in sky-view is nulled by the imprecision caused by the swaying?
- if mounted on tribrach, can I find a suitable measuring point for instrument height? (expeically true when using extension rods)
- do I trust my extension rod+adapters to be perfectly straight?
In answering all these questions for my self, I find that for the RS2 I do the following:
- setup a tripod with the usual recommendations for when setting it up for a total station
- assemble RS2, 15 cm Emlid extension rod, 5/8" to 20 mm tribrach adapter and tribrach.
- put it on the tripod
- level and align tripod/tribrach
- measure height to bottom of the RS2
- add 0.134 meters (this usually totals an antenna-height of just under 2 meters)
- good to go.
This I use in most situations, but I also have 0.5 and 1 meter extension rods for use in heavily vegetated or build-up areas. However, I’d rather move my base than use the rods, if possible.