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Selecting The Optimal 700MHz LTE Antenna For Public Safety Communications Part Three

The requirements for higher speed communications links continue to grow as police fleets accelerate their data communications use.  This presents a constant challenge for network designers and systems designers for fleet antennas.  While 4G LTE fleet antennas are currently being deployed, talk of 5G is just on the horizon.  Therefore, deployment of multi-frequency MIMO antennas that support LTE, WiFi and GPS bands public safety industry is necessary.  Offering a low V.S.W.R., robustness and a sleek design is equally as important as combined, these capabilities will ensure reliable, quality and secure communications within the 4G LTE band and beyond.

In three parts, Mobile Mark discusses the major trends and challenges facing the public safety industry and provides solutions to emergency responders’ communications obstacles:

Part One of Selecting the Optimal 700MHz LTE Antenna for Public Safety Communications discusses, in detail, the key challenges facing the public safety industry.

Part Two of Selecting the Optimal 700MHz LTE Antenna for Public Safety Communications delineates how an antenna which accommodates several frequencies can enable emergency responders to seamlessly transition between communication systems.

Part Three of Selecting the Optimal 700MHz LTE Antenna for Public Safety Communications highlights the importance of using an antenna with low V.S.W.R., ensuring the mechanical quality of the antenna is robust and, concurrently, sleek in design.

Low V.S.W.R.
The voltage standing wave ratio (V.S.W.R) for fleet antennas should be tested by the manufacturer with one foot of cable to ensure that the true characteristics of the antenna have been measured and not masked by the effects of the coaxial cable.  Antennas that are characterized with long lengths of cable tend to corrupt the true measurement by flattening the V.S.W.R. curve because of loss in the cable itself.  If the antenna is not truly tuned, extra losses will occur in the system.  A V.S.W.R. of 2:1 or less is required for optimum system performance.  A high V.S.W.R. number can reduce antenna efficiency by 10 to 20 percent.

Review the published specs carefully and be cautious with vendors reporting V.S.W.R. higher than 2:1 or those not stating the cable length that was used during testing, as this can be indicative of performance issues.

Robustness and Design
Police fleet vehicles necessarily operate at high speeds, over long distance and in harsh weather conditions, making it important to choose an extremely robust antenna solution.  Using a vendor with experience developing fleet antennas for mobile installations guarantees durability in the field.

Modern fleet antennas should also feature a design that matches the sleet look of new public safety vehicles. Aside from being aesthetically pleasing, a fully encased antenna design will be more reliable in the field. Traditional, large whip antennas are susceptible to damage and accidental impact and should be replaced by antennas with low profile, contoured characteristics.

At this point, no decision has been made about what frequency bands 5G will use but the decision will likely rely on current bands while using newer technologies such as 6X or 8X MIMO to double current data rates. Anticipating this scenario, LTE antenna designers are studying methods to add more MIMO elements into designs for next-generation fleet antennas.

Emergency response vehicles, appropriately equipped with these advance fleet antennas, will remain on the cutting edge of communications.  Mobile Mark is prepared to assist with your public safety industry needs to integrate fleet antennas into communications systems.  Contact Mobile Mark at, 1-800-648-2400 or 847-671-6690.

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