A tall tripod when you need it
There are not many users of borehole antennas that would say they don't need a survey tripod. At the same time there are not many users of tripods for borehole antennas that would say they need 1.5 meters clearance under the pulley for the cable, and rightly so. None the less, there are those who do need that clearance because the borehole housing is protruding from the ground quite a distance. We got such a request from one of our partners in Germany and were very surprised at first, then started to work and the project became much more interesting than we would have thought.
A tripod model that we designed a few years ago for another company had a fixed junction point at the top. In this particular case we could not go with that option simply because the customer might want to use the tripod closer to the ground and then the radius of the spreaded legs would have resulted impractical. A movable joint at the top was the solution we came accross. The carriage for the pulley and the rest of the construction was an easier task and when we finally got everything together were very pleased with the aesthetics of the unit as well as the mechanical properties of it. We highly disagree with the notion that rugged equipment has to be ugly by definition. The GTP-901 is not only rugged and reliable, but also nice looking and very light.
All the parts of the GTP-901 are made of fiber glass, sturdy plastic joints and custom milled POM parts. This makes a very lightweighted unit and at the same time avoids unnecessary use of metal parts in the unit. We were forced to use metal in some parts of the unit like the feet, main shaft, anti spread chain and securing bolts.
The pulley also counts!
In the pulley for the borehole cable there is an embedded magnetic ring that works with the encoder ENC820 to provide the customer with distance information. This is extremely nece ssary since no wheels can follow the antenna into the borehole and precise positioning of the antenna is vital many times during ground penetrating radar surveys.
What else do you need?
Obviously you need a cable that can connect to our encoder, but that you can find in the cables section of this website. Another thing that is recommended while not entirely necessary is display unit ECU901 to visualize the distance the cable has gone into the borehole.