INSTALLATION
ANTENNA CONSIDERATIONS
The FTM-10Ris designed for use with antennas presenting an impedance of near 50 Ohms at all operating frequencies. To avoid damage that could result if transmission occurs acci- dentally without an antenna, the antenna (or a 50 Ohm dummy load) should be connected whenever the transceiver is turned on.
Ensure that your antenna is designed to handle 50 Watts of transmitter power. Some mag- netic-mount mobile antennas, designed for use with hand-held transceivers, may not be capable of withstanding this power level. Consult the antenna manufacturer's specification sheet for details.
Use high-quality 50-Ohm coaxial cable for the lead-in to your FTM-10Rtransceiver. All efforts at providing an efficient antenna system will be wasted if poor quality, “lossy” co- axial cable is used. Losses in coaxial lines increase as the frequency increases, so an 8- meter-long (25’) coaxial line with under 1 dB of loss at 144 MHz may have a loss of 3 dB or more at 446 MHz. Choose your coaxial cable carefully based on the installation location (mobile vs. base) and the overall length of the cable required. (For very short runs of cable in a mobile installation, the smaller, more flexible cable types may be acceptable.)
For reference, the chart below shows approximate loss figures for typically available co- axial cables frequently used in VHF/UHF installations.
Loss in dB per 30 m (100 feet) for Selected 50-Ohm Coaxial Cables
(Assumes 50-Ohm Input/Output Terminations)
CABLE TYPE | LOSS: 144 MHZ | LOSS: 430 MHZ |
RG-58A | 6.5 | > 10 |
RG-58 Foam | 4.7 | 8 |
RG-213 | 3.0 | 5.9 |
RG-8 Foam | 2.0 | 3.7 |
Belden 9913 | 1.5 | 2.9 |
Times Microwave LMR-400 | 1.5 | 2.6 |
7/8” “Hardline” | 0.7 | 1.3 |
Loss figures are approximate; consult cable manufacturers’ cata- logs for complete specifications.
In outdoor installations, be certain to weatherproof all connectors thoroughly, as water entering a coaxial cable will cause losses to escalate rapidly, thus diminishing your commu- nications effectiveness. The use of the shortest possible length of the highest quality coaxial cable that fits within your budget will ensure the best performance from your FTM-10R.
Your dealer should be able to assist you with all aspects of your antenna installation re- quirements.
