User Manual

TN131C 915A Radio Operational Requirements
Lawrence Gordon Page 7 of 8 Last saved on 27-Mar-06 5:45 PM
F:\Tech Notes\TN131C - 915A Radio Operational Requirements.doc
If the 915A radio is powered by a supply other than the AC lines (e.g. vehicle power) then no
testing is required.
B.22.5 Antennas
Only antennas that have been approved by FCC and IC shall be used with the 915A radio. This
means that any antenna of the same family with a gain less than or equal to the approved antenna
can be used.
The list of approved antennas is given in Appendix A, which will be updated as new antennas are
approved.
The 915A radio is initially approved with the WaveRider Indoor Diversity Antenna (4.4 dBi) and
a YAGI (13 dBi).
However, the 915A radio is approved for 27.3 dBm output power at the antenna port and FCC
and IC rules require the peak radiated power be no more than 36 dBm, so a maximum of 8.7 dB
gain is allowed for the antenna system, which includes the antenna gain in dBi and any losses
between the 915A radio and the antenna, including cable losses, insertion losses at filters and
surge protectors etc.
Therefore if a 13 dBi YAGI antenna is used, then the losses must be at least 4.3 dB (27.3 + 13 –
4.3 = 36 dBm). A rule of thumb is that the losses must equal Antenna Gain (dBi) – 8.7.
This information shall be clearly noted in any installation manual for the final product.
It is also required that warnings be included in the installation manual regarding separation of
people from the antennas.
• Indoor antennas are limited to gains of 7.5 dBi or less, including cable losses. This limts
the totoal EIRP to 34.8 dBm. Indoor antennas must be installed so that people are at least
20 cm from the antenna under normal conditions. The WaveRider Indoor Diversity
Antenna meets these requirements.
• Outdoor antennas can support the full total gain of 8.7 dBi for the antenna system, for a
maximum EIRP of 36 dBm. Outdoor antennas must be installed so that people are
normally at least 30 cm from the antenna.
B.3
2.6 External RF Connectors
The 915A radio can be manufactured by WaveRider with a variety of external RF connection
options. The following requirements apply:
• WaveRider proprietary, unique external connector – This connector is externally
accessible and can be used on any final product.
• No RF connector – Final products with an integrated, approved antenna (i.e. no RF
connector externally accessible).
• Standard external RF Connectors (e.g. SMA or N type) – Final products that have
standard externally accessible RF connectors can only be installed by professionals. The
installation guide for these products must make this clear. The guide must provide
sufficient instruction to the installer for a successful installation.