Exalt Installation and Management Guide
EX-r Series GigE Digital Microwave Radios
201872-003
30
2015-10-23
The manufacturers of transmission line typically offer instruction and certification for transmission
line termination, and may also provide videos illustrating the process. There is no amount of extra care,
education, precision, and effort that can be overstated for this process.
There is often a need for a small excess of transmission line near the antenna to accommodate both the
need for extra slack as the antenna is loosened and moved for the alignment process, and to
accommodate a drip loop for the transmission line and the initial transmission line securing hardware
and grounding near the antenna. In addition, the transmission line is typically very stiff, and can
provide undue pulling force on the antenna or radio connector. Take care to align the cable with the
connector so that it does not provide any torque or strain on the connector.
Consult your transmission line manufacturer for the proper transportation, hoisting, securing, and
grounding process. Always be very mindful of the entire length of transmission line to ensure that the
transmission line is never twisted, kinked, or over-bent beyond the specified bend radius. Once a
transmission line is over-bent or kinked, it will likely never recover its specified characteristics, even
after straightening, and will often be completely unusable.
The opposite end of this primary transmission line typically terminates at the radio connector. If using
a long transmission line (in excess of 3'/1m), an RF lightning arrestor is recommended to protect the
radio equipment.
As soon as practical, weatherproof the connected ends of the transmission line to the antenna and
lightning arrestor and radio. This process should be delayed as long as possible to ensure that all
systems are working properly before applying the weatherproofing. Once weatherproofing is applied,
it may have to be removed for testing or installation modification. With this in mind, if the installation
is occurring during inclement weather, take extra care at all times to ensure that no moisture enters any
connector at any time. If moisture is suspected to have compromised the antenna or transmission line,
it may render those devices useless without any means for remedy except for full replacement.
Cap and weatherproof the second antenna connector on the radio if using a single-polarity antenna.
Indoor Mounting
On rare occasions the antenna can be mounted indoors behind a window. In these cases, there would
not be a need for drip loops or an RF lightning arrestor. Use a very short transmission line connected
directly between the antenna and the radio mounted nearby. The weatherproofing process can also be
omitted.
RF Lightning Arrestor
RF lightning arrestors provide a direct path to ground for lightning strikes that may couple to or
directly hit the outdoor transmission system or antenna structure. The RF lightning arrestor prevents
any associated voltage and current from entering the radio equipment, other equipment, or humans.
The following lightning arrestors are examples of proper devices for Exalt Digital Microwave Radios:
•
Polyphaser AL-LSXM
•
Andrew BB-BNFNFE-26
Mount and ground the RF lightning arrestor in accordance to the manufacturer’s recommendations.
Place it as close as possible to the radio equipment. Minimize the distance to the radio to lessen the
Caution:
Always follow the manufacturer’s termination process EXACTLY, and only use the
manufacturer’s authorized tools and connectors for a given transmission line type.
