Introduction

Field measurements were performed both at 144.360 MHz (VHF) and 445.900 MHz (UHF).

A vehicle was positionned at a fixed location and the other moved.

The fixed vehicle was transmitting periodic beacons.

A calibrated receiver in the mobile vehicle was used to measure the Rx signal.

The mobile vehicle was also equipped with a GPS receiver, so each measurement was associated with a lat-lon position.

Test setup diagram

Test vehicles

Path loss was calculated knowing Tx power and antenna gain.

The position recorded and system parameters were entered in Radio Mobile to compute path loss.

The Spot mode was selected to resume the probability of success to a single statistical percentage.

Forest or city percentage were used according to test conditions.

Spot percentage and forest/city percentage were adjusted to best fit the measured values.

Forest percentage of 30% corresponds to an eastern canadian low density pine forest.

City percentage of 30% corresponds to an average low density canadian city.

Test 1 - Rural flat terrain with no trees - Site 1 Poor siting

Photo of rural flat terrain used

Test 1 route

Test 1 VHF measured path loss

Test 1 VHF Radio Mobile predicted path loss with Spot at 50%

Test 1 VHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 1 VHF Radio Mobile predicted path loss with Spot at 90%

Test 1 UHF measured path loss

Test 1 UHF Radio Mobile predicted path loss with Spot at 50%

Test 1 UHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 1 UHF Radio Mobile predicted path loss with Spot at 90%

Test 2 - Rural Flat terrain with no trees - Site 1 Careful siting

Photo of careful siting on the slope of the mountain

Test 2 route

Test 2 VHF measured path loss

Test 2 VHF Radio Mobile predicted path loss with Spot at 50%

Test 2 VHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 2 VHF Radio Mobile predicted path loss with Spot at 90%

Test 2 UHF measured path loss

Test 2 UHF Radio Mobile predicted path loss with Spot at 50%

Test 2 UHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 2 UHF Radio Mobile predicted path loss with Spot at 90%

Test 3 - Urban flat terrain

Photo of urban flat terrain used

Test 3 route

Test 3 VHF measured path loss

Test 3 VHF Radio Mobile predicted path loss with Spot at 50% and City at 30%

Test 3 VHF Radio Mobile predicted path loss with Spot at 70% and City at 30% Best fit

Test 3 VHF Radio Mobile predicted path loss with Spot at 90% and City at 30%

Test 3 UHF measured path loss

Test 3 UHF Radio Mobile predicted path loss with Spot at 50% and City at 30%

Test 3 UHF Radio Mobile predicted path loss with Spot at 70% and City at 30% Best fit

Test 3 UHF Radio Mobile predicted path loss with Spot at 90% and City at 30%

Test 4 - Rural flat terrain with trees

Photo of rural flat terrain with trees used

Test 4 route

Test 4 VHF measured and predicted path loss comparison with Spot at 70% and Forest at 30%

Test 4 UHF measured and predicted path loss comparison with Spot at 70% and Forest at 30%

Test 5 - Rural hilly terrain with few trees - Site 1 Poor siting

Photo of rural hilly terrain used

Test 5 route

Test 5 VHF measured path loss

Test 5 VHF Radio Mobile predicted path loss with Spot at 50%

Test 5 VHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 5 VHF Radio Mobile predicted path loss with Spot at 90%

Test 5 UHF measured path loss

Test 5 UHF Radio Mobile predicted path loss with Spot at 50%

Test 5 UHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 5 UHF Radio Mobile predicted path loss with Spot at 90%

Test 6 - Rural hilly terrain with few trees - Site 1 Careful siting

Photo of view from careful siting location

Test 6 route

Test 6 VHF measured path loss

Test 6 VHF Radio Mobile predicted path loss with Spot at 50%

Test 6 VHF Radio Mobile predicted path loss with Spot at 70% Best fit

Test 6 VHF Radio Mobile predicted path loss with Spot at 90%

Test 6 UHF measured path loss

Test 6 UHF Radio Mobile predicted path loss with Spot at 50%

Test 6 UHF Radio Mobile predicted path loss with Spot at 70% Best fit, but a bit pessimistic

Test 6 UHF Radio Mobile predicted path loss with Spot at 90%

Test 7 - Urban hilly terrain

Photo of urban hilly terrain used

Test 7 route

Test 7 VHF measured and predicted path loss comparison with Spot at 70% and City at 30%

Test 7 UHF measured and predicted path loss comparison with Spot at 70% and City at 30%

Conclusion

Radio Mobile set to Spot mode at 70% is the best fit for all tests.

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