iGage
iG8 User Manual
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The ‘BaoFeng UV-5R’ is available from Amazon for less than $25 and is a good-enough choice for monitoring frequencies:
Become familiar with what it sounds like if you are the only user on a frequency and what it sounds like if there are more
than one user on the same frequency.
Sources of interference include:
other surveyors and engineers
voice users (truckers, businesses, railroads, schools, service companies)
wireless microphones
SCADA equipment (like water or oil pipeline infrastructure)
control backhauls on com links
nearby AM or FM radio transmitters
nearby radar systems
The radio frequencies that are generally assigned (by the FCC in conjunction with frequency coordination) are not
exclusive and are assigned to multiple users in the same area.
By FCC rules, even unlicensed voice transmissions have a higher priority than licensed data transmissions. Your radio (the
radio built into your base) will wait for other users before it transmits (this is called CSMA: collision sense multiple
avoidance.)
If you find that the frequency that you were going to transmit is busy, you can change the channel/frequency of your
base and rover to an alternate frequency. The radio frequency is set on the Rover is under “Equip: GPS Rover: RTK (tab):
Internal UHF Radio Settings”.
Base Output Power Setting
You probably will want the radio in your base to output as much power as possible. The setting for the base output
power is under “Equip: GPS Base: RTK (tab): Internal UHF Radio Settings”.
If 1-watt is not sufficient, then we recommend purchasing a high-power repeater.
Minimize CSMA
Your base radio is required to not transmit when there are other users on the same frequency: Collision Sense Multiple
Avoidance.
This is an FCC requirement and cannot be disabled. However, the FCC does not specify how carefully we need to listen for
adjacent traffic. So we set the receive sensitivity on the base to ‘Low’.
The setting for the base output power is under “Equip: GPS Base: RTK (tab): Internal UHF Radio Settings”.
Bad Antennas
The UHF antennas on most GNSS equipment get beat around quite a bit. The antennas on the base and extension pole
get whipped around in the wind a lot.
If you suspect that you have a bad antenna, we recommend that you purchase two spare antennas and change out both
your base and rover. If the problem goes away, then you know that one (or perhaps both) of your original antenna have
failed.
Call iGage for ‘Original Equipment’ antennas (the black ones) and special extended range models.
