Task

As GIS specialists, we are tasked by the commanding officer with the establishing deployment site(s) of a signal tower(s) that will act as a relay station in order to establish communication with the platoon. The signal mask has a frequency coverage of 12 km, when erected is 5 meters in height. In the accordance with the military doctrine, the signal towers must not be deployed with 2 kilometres of any residential areas or industrial areas. Develop a suitable model to identify the possible deployment and erection site(s) of the signal tower. 

Elevation Maps (2)

Figure 9: The elevation value

Figure 10: The elevation value

Elevation Maps

Figure 7: The elevation value

Figure 8: The elevation value

Town Buffering according to the constraints

Figure 4: Buffer zone around towns

Figure 5: The border of the Saldanha municipal with its buffered town

Map of area of interest

Figure 2:The Saldanha Bay Municipal border and its towns

Municipal Boundary

Figure 3: Saldanha Municipal Boundary

Conclusion

Based on the results of the spatial analysis used, between St. Helena bay and the HQ ( 4 Special Forces Regiment). There are several points that have higher elevation for the mast however some were not visible from the viewpoint of choice. A Spatial analyst tool was used to test for visibility and non-visibility. This tool among the other tools that were used, enabled us to identify the Possible deployment position. The criteria for such selection was mainly based  on viewshed and elevation. 

Types of Antennas

•In the Military, the following antenna are used:

i.Vertical Rod

ii.Sloping Rod Antenna

iii.Dipole

iv.Inverted V

v.Discone

Amongst others but we will focus on the Discone antenna

Discone

•When erected it is 6 meters long and it covers a range of 12 kilometers.

•It operates between a frequency of 2-30 MHz Conical Monopole.

•A field-deployable wideband vertical omni, which can be erected by two persons in a short time. Portable and can be used with the High frequencies radios such as the  A55, A43 and B46 radio.

Deployment Position

Figure 6: The several deployment points. These points were selected at random but after considering their elevation and viewshed. The figure 6(a) below illustrates the possible deployment points that does not violate the constraints.

Figure 6 a: Possible point where the antenna can be mounted. these points were chose based on their elevation

Recommendations

Military mast operates with the line of sight and it has a short range coveragee, so more than pme mast needs to be erected if covering long distances and unfavourable terrain. They are essentially potential target in any conflict. The depployment therefore has to be done in such a way as to conceal them from the opposition force,while getting the maximum operational use

As a GIS Specialist, after the spatial analysis of the area of interest. We have identified 5 best possible points where the antenna(s) can be mounted as relay stations. It would be on the Units' advantage to use all 5 points that we identified to ensure effective communication line between the platoon and HQ

Figure 16: The recommended points for signal tower erection

Viewshed

Figure 11: Viewshed of the Point 1 

Figure 12: Viewshed of the Point 2

Viewshed

Figure 13: Viewshed of the Point 3

Figure 14: Viewshed of the Point 4

Figure 15: Viewshed of the Point 5

Introduction

     The beginning of 20th century (until WW2) marks the boom in wire antenna technology (dipoles and loops) and in wireless technology as a whole, which is largely due to the invention of the DeForest triode tube, used as radio-frequency (RF) generator. Radio links are realized up to UHF (about 500 MHz) and over thousands of kilometres (1).

    The antenna is the transition between a guiding device (transmission line, waveguide) and free space (or another usually unbounded medium). Its main purpose is to convert the energy of a guided wave into the energy of a freespace wave (or vice versa) as efficiently as possible, while at the same time the radiated power has a certain desired pattern of distribution in space (1).

Problem statement

A group of poachers are in the St Helena town, the SANDF had an anti-poaching unit in the West Coast area. The unit has its HQ at 4 Special Force regiment, they have a platoon deployed 1 km outside St Helena. The HQ had a problem establishing contact with the platoon due to the geography of the area.

References

1. http://www.ece.mcmaster.ca/faculty/nikolova/antenna dload/current lectures/L01 intro.pdf, page 1 &3
2. Google earth
3. ArcGis

Signal Antenna Type

Introduction

A device capable of the transmission and reception of electromagnetic waves of radio

frequency, especially those carrying sound messages.

The antenna is the part of the device from which the energy is radiated into space. 

This radiated energy is in the form of electromagnetic radio waves which travel at a speed  

of about 300 000 000 m/s.

Type of signal mask

Figure 1: A 5 meter signal antenna.

Specifications

• 2-30 MHz Conical Monopole
• A field-deployable wideband vertical omni, which can be erected by two persons in a short time. Portable and can be used with the A55 radio, A43 radio and B46 radio.
• It has a frequency coverage of approximately 12 kilometers

Establishing deployment site(s) of a signal tower(s)

Constraints:
1. Deploy 1km outside St Helena
2. The signal mask has a frequency coverage of 12 km
3. Signal tower must be 5 meters in height
4. Signal tower must not be deployed within 2 km of any residential or industrial areas