MFD transmitter antenna

[Napsterce]

What's the best type of antenna to be used to transmit signal from function generator to the earth? I have seen a lot of MFD devices that use two ground probes but i have also seen a lot with a coil antenna built inside the box of the transmitter without probes or anything. Any opinion on this?

[UltraLRL]

Just Look for the best antenna radiation pattern for your design.

http://www.antenna-theory.com/antennas/norm3D1lam.jpg

Also antenna gain and length is matter.

See the PDF for more info.