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FOLDED UNIPOLE FAQS

Hundreds of AM broadcasters across the US and worldwide have found the installation of a Tunipole™ and Combipole™ Antenna Systems to be a first-class benefit for their stations. The overwhelming choice of these broadcasters is the LBA Technology, Inc. Tunipole™! Unique in the broadcast industry, the Tunipole™ is an approach to total folded unipole system design, engineering, manufacturing, and installation support. We at LBA Technology, and our qualified dealers throughout the world, will work with you to ensure that your Tunipole™ folded unipole antenna gives your station the best performance in the market!

Which Tunipole™ Folded Unipole Antenna System should be specified?

LBA Technology research and development has produced four standard models to suit virtually every application. The Tunipole™ folded unipole can be installed on self supporting towers, and towers of unusual design, so be sure to call us to discuss your requirements. We will help you make the right choice for your station. 

Standard Models Available

UP-311

3 foldwires, maximum height 600 feet (180m), power to 5kW

UP-352

3 foldwires, maximum height 600 feet (180m), power to 25kW

UP-611

6 foldwires, maximum height 600 feet (180m) power to 10kW

UP-651

6 foldwires, maximum height 600 feet (180m), power to 50kW

CUSTOM

A wide range of custom systems can be designed to meet your needs.
Call for a quotation.

 

Will the Tunipole™ change my station’s antenna characteristics?

Typical installation of a Tunipole folded unipole antenna systemInstallation of a Tunipole™ folded unipole system changes the way in which a steel AM tower is fed radio frequency energy. However, the radiating characteristics of the tower remain essentially unchanged. This is true regardless of where the Tunipole™ is terminated on the tower, or how tall the tower is. As far as efficiency of the antenna goes, it follows theoretical prediction closely, whether the wires extend one-half of the way, or the entire way, up the tower. In other words, installing a Tunipole™ folded unipole system on the bottom 200 feet of a 400 foot tower does not mean that only the bottom 200 feet will put out a signal - the entire tower does. However, the physical arrangement of the Tunipole™ on the tower can have a great deal of effect on matching and bandwidth of transmissions. Our experts will recommend the most cost-effective arrangement for your station.

TYPICAL MECHANICAL-ELECTRICAL DATA

  UP-311-200 UP-351-200 UP-611-200 UP-651-200
Frequency Range: 500-2500 khz 500-2500 khz 500-2500 khz 500-2500 khz
Power Rating: 5,000 watts 25,000 watts 10,000 watts 50,000 watts
Impedance Range (frequency dependent): 10-300+/-j 350 ohms  10-300+/-j 350 ohms  10-300+/-j 350 ohms  10-300+/-j 350 ohms 
Lightning Protection: DC Ground DC Ground DC Ground DC Ground
Windload (100 mph): 300# (135 Kg) 600# (270 Kg) 600# (270 Kg) 1200# (540 Kg)
Download: 500# (225 Kg) 700# (315 Kg) 1000# (450 Kg) 1400# (630 Kg)
Weight: 125# (56 Kg) 200# (90 Kg) 250# (113 Kg) 400# (180 Kg)
Insulation: Epoxy
Fiberglass
(anti-UV coated)
Steatite, Epoxy
Fiberglass
(anti-UV coated)
Epoxy
Fiberglass
(anti-UV coated)
Epoxy
Fiberglass
(anti-UV coated)

 

How does the Tunipole™ folded unipole antenna compare with my base insulated series-fed antenna?

It is better in every way! Field experience proves bandwidths as much as 100% greater than series-fed. Tests over an abbreviated ground system have shown efficiencies as much as 400% greater. Then there are all the other benefits also discussed here. Truly, there is no reason to build a series-fed tower - and every reason to convert your existing one!

 

COMBIPOLE™ MULTI-STATION FOLDED UNIPOLE

Now the LBA folded unipoles may be used to feed two or three Medium Wave transmitters into one antenna tower. The unique Combipole™ not only permits the independent feed of as many as three MW transmitters to one tower, but permits independent impedance control at each frequency! Power levels to over 1,000,000 watts are available. Systems can be supplied to include towers, ground systems, and tuning/filter units.

 

What about construction and durability?

Tunipole™ folded unipole antenna systems are designed for long life! They are constructed utilizing ultra-violet resistant fiberglass, hot dip galvanized steel, heavy duty steel-reinforced aluminum cable, and custom hardware. Careful attention has been given to corrosion prevention at dissimilar metal joints for long and stable operation. Unique to the LBA Technology, Inc. Tunipole™ is our calibrated Delta Tension Unit, which permits accurate adjustment of tension on the Tunipole™ foldwires. Furthermore, our systems maintain that nominal tension over a variety of environmental conditions. A UP-311 typically adds only 300 pounds of windload to a tower, distributed evenly along its length - less than that of a single 7/8" coaxial cable! Properly installed, Tunipole™ folded unipole antennas are designed to survive winds in excess of 100 miles per hour.

 

FLEXIBLE ANTENNA IMPEDANCE SELECTION:

Resistance and reactance parameters seen at the feed-point are variable by physical unipole adjustment. A wide range of impedances is possible. Existing Antenna Tuning Units can frequently be used with little modification.

 

TESTED AND PROVEN:

Designed by broadcast consultants for the special needs of AM medium wave broadcasting worldwide, the LBA Tunipole™ folded unipole is the only system with a 25 year record of high performance. Hundreds of installations worldwide attest to the quality of the LBA Tunipole™ folded unipole antenna. All Tunipoles™ and Combipoles™ are backed by a conditional one year warranty.

 

How difficult is installation?

As is the case with any tower work, installation should only be performed by competent and properly equipped riggers. For such an installer, the procedure is simple and rapid. System components have been fabricated in such a way that most installations can be accomplished by one rigger in the air with a ground helper, a lifting rope, and ordinary hand tools. Many installations are made in less than eight man-hours. Adjustment and tuning is typically a one day process by our field engineer, the station consulting engineer or appropriately skilled and equipped staff. Installation instructions and prints are furnished with the systems. When ordering, any unusual factors which could hamper installation should be brought to our attention so that adaptions may be considered prior to fabrication. Essentially no maintenance is required after installation, although systems should be inspected periodically for damage, particularly after wind or ice storms.

 

I want to install communications antennas on my tower - can I do that?

Yes! LBA has developed the CoLoPole™ to facilitate the installation of communications, cellular and PCS systems on AM towers. A close cousin to the Tunipole™, the CoLoPole™ shares all the electrical features of the Tunipole™ with special elements just for collocation. Read more about AM tower co-location, including the revolutionary new CoLoCoil™ for directional AM systems.

 

What additional systems and services are available?

Complete Tunipole™ folded unipole antenna packagesComplete Tunipole™ folded unipole antenna packages are available to meet your specific needs. In new construction, or in the reconstruction of older stations, the LBA Technology, Inc. TTU series of Tunipole™ Tuning Units is an ideal complement to your antenna system. This custom designed tuning unit will provide optimal matching for your new Tunipole™. For existing tower conversions, we can recommend and supply necessary conversion parts. LBA Technology is also your source for coils, capacitors, coaxial cable, copper ground wire, strap, ground screens and other RF supplies. LBA Technology is a one-stop shopping service for AM antenna system requirements. We will save you hours of searching for sources of supply for these items.

 

 

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CONTACT INFO

3400 Tupper Drive,
Greenville, NC 27834, USA

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About LBA

LBA Group companies serve technical infrastructure needs related to the broadcast, wireless, electromagnetic compatibility and safety sectors worldwide. We provide consulting, training and other telecommunications industry services. We also produce and market hardware for radio transmission, RF shielding, safety and testing.

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