Loss figures are approximate; consult cable manu- facturers’ catalogs for complete specifications.

INSTALLATION

ANTENNA CONSIDERATION

The FT-2800Mis designed for use with antennas presenting an impedance of near 50 Ohms at all operating frequencies. The antenna (or a 50 Ohm dummy load) should be connected whenever the transceiver is turned on, to avoid damage that could otherwise result if transmission occurs accidentally without an antenna.

Ensure that your antenna is designed to handle 65 Watts of transmitter power. Some magnetic -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.

Most all FM work is performed using vertical polarization. When installing a directional antenna such as a Yagi or Cubical Quad, be certain to orient it so as to produce vertical polarization, unless you are engaged in a special operating situation where horizontal polarization is used. In the case of a Yagi antenna, orient the elements vertically for vertical polarization; for a Cubical Quad, the feedpoint should be at the center of one of the vertical sides of the driven element (or at a side corner, in the case of a diamond-shaped Cubical Quad).

Excellent reference texts and computer software are available for the design and optimization of VHF antennas. Your dealer should be able to assist you with all aspects of your antenna installation requirements.

Use high-quality 50 Ohm coaxial cable for the lead-in to your FT-2800Mtransceiver. All efforts at providing an efficient antenna system will be wasted if poor quality, lossy coaxial cable is used. Losses in coaxial lines increase as the frequency increases, so an 8-meter-long (25’ coaxial line with 1/2 dB of loss at 29 MHz may have a loss of 1.8 dB or more at 146 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 at the right shows ap-

Loss in dB per 30 m (100 feet) for

proximate loss figures for typically-available

Selected 50-Ohm Coaxial Cables

coaxial cables frequently used in VHF instal-

(Assumes 50-ohm Input/Output Terminations)

lations.

CABLE TYPE

LOSS: 144 MHZ

 

In outdoor installations, be certain to weather-

RG-58A

6.5

 

RG-58 Foam

4.7

 

RG-213

3.0

 

proof all connectors thoroughly, as water en-

 

RG-8 Foam

2.0

 

tering a coaxial cable will cause losses to es-

Belden 9913

1.5

 

calate rapidly, thus diminishing your commu-

Times Microwave LMR-400

1.5

 

7/8” “Hardline”

0.7

 

 

 

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 FT-2800M.

6

FT-2800M OPERATING MANUAL