1. Transmission Frequency
The NRP transmitter is continuously tunable over the range 5450 Mhz to 5825 Mhz
Operational fixed frequency of 5625 Mhz is preferred
Recall : c=nl
Thus, 5625 MHz corresponds to a microwave wavelength of 5.33 cm (C band)

2. Weather Radar Bands
The more common weather radar wavelengths and letter designations are:

3. Frequency
The choice of frequency is important for a number of reasons:
attenuation in precipitation is stronger at shorter wavelengths and is especially strong below 5cm
the antenna size must scale with the wavelength to provide the same beamwidth: e.g. an antenna for an S band radar must be twice as big as for a C band

4. Pulse Repetition Frequency (PRF)
The pulse repetition frequency (PRF) is the number of pulses emitted by the radar per second (pps)
A pulse travelling to a target at range rmax and back will cover a distance 2rmax
The pulse will make it back to the radar before the next pulse is emitted if:
2rmax=c/PRF

5. PRF and radar range rmax=c/2PRF
Or….
rmax=c/2PRF
Thus, the higher the PRF, the lower the effective range (ignoring second-trip echoes from objects located beyond rmax)
But the lower the PRF the fewer samples the less reliable.

6. Rmax vs PRF

7. Rmax in selected modes
We will see in a little while why we have to use higher PRF’s for Doppler