Exalt Communications, Inc.
r-series
Installation and Management Manual
5000007 (ETSI)
31
2007-02-12 (draft)
termination, which may not have considered the frequency of your system. When buying pre-
terminated transmission line, it is strongly advised to obtain the documentation of test
measurements on the connected transmission line showing that the loss characteristics and
VSWR are within the specified limits specifically at your operating frequency. In addition to
factory-built transmission line, self-terminated transmission line can suffer the same issues.
Always follow the manufacturer’s termination process EXACTLY, and only use
the manufacturer’s authorized tools and connectors for a given transmission line
type.
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.
CAUTION