The Topcon DT-207 and the Topcon DT-207L are part of the Topcon DT-200 series of theodolites. They have remained unchanged for a number of years, testament to the design of the theodolite.
These theodolites are straight forward to use and fast to setup, ideal for busy construction sites. The screen and interface on the Topcon DT-200 series is simple to use and easy to see thanks to the large display that is a backlit LCD screen. The large display shows both horizontal and vertical angle in the degrees, minutes, seconds format and also displays the battery status. The Topcon DT-207 and the DT-207L come with displays on both faces as standard.
Every theodolite in the range comes with an integrated optical plummet, making setting up over know point a doddle. Read this guide to setting up a theodolite above a known point for easy and quick setup of a theodolite, Theodolite setup guide.
The Topcon DT-207 has 30x magnification along with a very short minimum focusing length of 1m (or 3 foot). Opt for the Topcon DT-207L and you get a red laser pointer (class II) that emits directly from the lens. This can be seen in direct sunlight about 50m from the theodolite. This is a very handy feature when trying to line in bolts or measure offsets from a line.
The Topcon DT-207 and the DT-207L are powered by 4No. AA batteries which last up to 150 hours in continuous angle measurement mode. With the Topcon DT-207L, the batteries will last up to 45 hours with the Laser pointer in use. This is still a full week of work on most construction sites. For best results we would advise using alkaline batteries instead of NiCad rechargeable batteries.
The Topcon DT-207 and the DT-207L has an IP66 rating, which means it protected against dust that may harm the instrument and is protected from low pressure water jets. It also has an operating range from minus 20 degrees Celsius to 50 degrees Celsius.
The Topcon DT-207 and the DT-207L are accurate to 7 seconds, a unit of angular measurement. In the real world at 200m away from the Topcon DT-207 you would could expect to be sighting within 4mm, either side, of your desired point. If you use both faces when taking measurements then you can reduce this error.
The Topcon DT-207 and DT-207L are the mid level theodolites of the Topcon DT-200 Theodolite range. The other Theodolites in this range are the Topcon DT-209, Topcon DT-209L, Topcon DT-205 and the Topcon DT-205L.
Selecting the right theodolite for you is just the first step in getting accurate results, you need to know how to set up, check and use the theodolite. Read these handy guides on how to set up a theodolite above a known point and how to check a theodolite.
If the Topcon Theodolites are not for you, then you can always check out these alternatives and check out the latest prices.