INSTALLATION AND MAINTENANCE MANUAL
E1 FAMILY
LICENSED & SPREAD SPECTRUM RADIOS
JUNE 2001
SECTION 2: PRODUCT DESCRIPTION
PAGE 3-35
3.3.6
Frequency Plan Determination
When configuring radios in a hub or repeater configuration, careful engineering of the
Lynx
radio
frequency plans and antenna locations should be performed in order to minimize potential
interference between the nearby radios. As a rule of thumb, do not place identical frequency plan
radios (
e.g.
two “A” channel radios) at the same site. In most cases, it is desirable to use a different
frequency plan (
e.g.
A versus B). However, with careful engineering, placing more than one radio of
the same frequency channel plan at the same site can be accomplished. In fact, the
Lynx
frequency
plan is designed to allow complex hub configurations that may require re-using the same frequency
plan. When designing these types of configurations, antenna size and antenna location are critical.
If identical channel plans must be used at the same site, the same radio channel (
e.g.
A1 and A1)
should be used at a site to minimize interference. Using alternate channels (
e.g.
A1 and A2) is less
likely to be successful (and therefore not recommended) due to the high level of transmitter to
receiver isolation required from the antenna system.
Sometimes it is required to locate the
Lynx
radio nearby a transmitter that is the same as, or close
to the
Lynx
receive or transmit frequencies. In this case, the
Lynx
terminal that should be placed
closest to this interfering transmitter should be the specific terminal with the receive frequency
which is furthest from this unwanted transmitted frequency. This approach minimizes the potential
of interference. While interference conditions are rare when using the
Lynx
radios, cases of
interference may be overcome by exchanging the radios from end to end or simply reinstalling the
filter unit, as described in Section 4.2 (thus swapping the frequencies of both ends of the radio link).
In some cases, changing frequency plans (e.g. from A to B) can also help mitigate any interference.
Section 4.8 of this manual describes interference
countermeasures in further detail.
