Antennas, much like speakers, are transducers. They convert Electrical energy to Electromagnetic energy. And just like some speakers are made for specific frequencies (Woofer, Mid-range, and Tweeters) so too are antennas. HF / VHF / UHF / SHF etc..
Know your Frequency.
Most radio systems used for long range communications in the Survey industry are in the UHF band. Some manufacturers use SHF (900MHz) radio systems. An antenna designed for 450MHz should NEVER be used on a 900MHz radio and vice-versa. The miss-match of frequency can damage the radio beyond repair.
Check your equipment manual specifications for the radio to determine what frequency you need.
Which connector do you need?
There is no industry standard for connector use. The result is that any given UHF antenna can have any number of connectors on it!
Picking the wrong connector is a show stopper.
Pay attention to the photos below. We point out specific areas to look at in order to identify the correct connector.
Antenna Connectors
RFT-Female Connector typically found on the Radio, GPS receiver or Robotic total station. The antenna that fits this has the RFT-Male connector and screws onto this connector. Note the center “socket” pointed out above. O.D. of the threads is 0.435″.
RFT-Male Connector. By far the most popular antenna connector in our industry. Note the center “pin” that fits the socket on the RFT-Female connector. If you are looking for an antenna for a Topcon GPS radio pay CLOSE ATTENTION to this center connection. Some Topcon receivers use a “reverse polarity” connector that looks similar but have the “socket” in the center of the Male connector. We will have a solution for those antennas in the near future.
RFB-Female connector. These were typically used on the Radios, and older GPS receivers, not Robotic total stations. The antenna that fits this has the RFB-Male connector and mounts via a 1/4 turn motion. Note the center “socket” and side “pins” pointed out above. O.D. of the smooth section is 0.477″.
RFB-Male connector. These were typically used on the Radio antennas and extension cables. RFB-Male connector mounts via a 1/4 turn motion. Note the center “pin” and side slot latch pointed out above. Most mfg’s have switched to the RFT connectors for better long term reliability.
RFS-Female connector. These look like the RFT connectors above but are much smaller, only 1/4″ O.D. These are normally found on WiFi devices and 900MHz systems.
RFS-Male connector. This would be found on the antenna or extension cable and we are seeing these appear on “dual band” radios. We will offer these as more information arrives about their use.
RFN connectors were used in the early days of GPS. We see them now mostly in the Machine Control systems.
RFN connectors were used in the early days of GPS. We see them now mostly in the Machine Control systems.