In May 2021, we carried out test measurements of signal levels from the base station of the conventional radio communication system in VHF and UHF bands (145 MHz and 430 MHz) in suburban/rural and forest areas.
We took these measurements for:
1. Comparative analysis of real measured received power values with the signal levels predicted in RadioPlanner 2.1
2. Comparison of the attenuation in different clutter types obtained experimentally with the attenuation values determined for the corresponding clutter type according to the recommendation ITU-R P.1814.
Test base station: Baofeng DM-1701 radio station operating in analog mode with an output power of 2-2.5 W, OPEK UVS-100 dual-band OMNI antenna, RG-6 cable. The transmitter output power, antenna VSWR, and cable attenuation were monitored for each frequency band before testing with Supercom SW-102 power meter and NanoVIVA-F vector analyzer.
Transmitter power measurement
Measuring the SWR of the transmitter
Measuring cable loss
Mobile measuring station: SignalHound USB-SA44B spectrum analyzer/measuring receiver, USB GPS receiver, OPEK VH-1210 (for 145 MHz) and OPEK UH-411 (for 430 MHz) antennas, laptop with proprietary measurement software. During the tests, the antenna of the mobile station was placed on the roof of the car.
Measuring mobile station
UHF antenna and GPS receiver on the car roof
Measurement track recording
We did not have an opportunity to place the BS antenna so that it was at a dominant height relative to the entire clutter. The antenna phase center was at a level of 9 m from the ground. This somewhat violates the scheme adopted for calculations in RadioPlanner, when clutter losses are taken into account only on the mobile station side. But, given that in a radius of up to 400-500 m from the BS, almost the entire clutter was below the antenna height, we assumed that this should not strongly affect the result.
Measurement area - rural area near the Beloyarka, Novosibirsk region. This is a flat territory with absolute values of terrain heights from 90 to 200 m with dense forests and low residential buildings with a height of 4-7 m.
Typical local woodland
Typical local settlement
For each frequency band, several test runs were performed, then, for the convenience of analysis, the tracks for one frequency band were combined, and, as a result, two tracks were obtained - for the VHF and UHF, with several thousand measurement points in each.
The prediction of receive power levels in RadioPlanner 2.1 was carried out using the ITU-R P.1812-4 propagation model with the exclusion of the location and time variability component (percentage of location and time = 50%).
Propagation model parameters:
Screenshots comparing measured and calculated receive power levels:
The analysis results were summarized in two tables for each of the frequency band:
Our conclusions based on the results of comparison of measurements and predictions in RadioPlanner:
1. The standard deviation of the measured values of the signal levels and levels predicted in RadioPlanner 2.1 for different clutter types is in the range of 4.6-7.6 dB. This is a pretty good result for a predictive tool that also shows the relevance of the ITU-R P.1812-4 propagation model and the spatial datasets used - DEM and clutter.
2. The obtained absolute clutter loss values, typical for rural and forest areas, are practically the same for the VHF and UHF bands.
3. For forest areas - forest and roads in the forest, the absolute clutter loss values obtained as a result of measurements, with an accuracy of 1-3 dB, coincide with the corresponding losses calculated according to ITU-R P.1812-4.
4. On an "open space" type clutter, measurements show additional attenuation of 9-11 dB. This can be explained by the fact that this is an area surrounded on all sides by a forest, despite the fact that locally a clutter in them is identified as an "open space."
5. The measured attenuation in the suburban clutter is 3-6 dB higher than that determined in ITU-R P.1812-4. We believe that this may be the result of the fact that the BS antenna was located just in a suburban clutter at a height only slightly higher than the average clutter height.
The comparative analysis showed good agreement between the measured values and the values of the signal levels predicted in RadioPlanner 2.1 in the VHF and UHF bands.