LA144 Wideband VHF Amplifier
135-175 MHz
LA144
VHF Linear Amplifier
135-175MHz
The LA144 is a wideband compact amplifier for the VHF band; covering from 135 to 175 Mhz. Output is
nominal 60W at full power (70W max).
Input drive from 0.5W to maximum of 4W, ideally suited to low power handheld transceivers. Output
power depends both on input power and frequency of use. The graph illustrates the relationship between
the two parameters. The amplifier features automatic RF switching between RX and TX. The diagram
below illustrates the connection details. The power cable for the amplifier should be kept as short as practicably possible and less than 3m in length. When used in a mobile installation it is recommended that the
power cable is connected directly to the auto battery. A safety fuse may be added at this position for protection against short circuit. 12 to 15A is sufficient as the amplifier is internally fused. The RF cable from the
transceiver to the amplifier and amplifier to the antenna must be kept as short as practicably possible and
be 50 Ohms impedance and suitable for the frequency of operation. The antenna must also be suitable for
the frequency of operation. The amplifier must be installed in a suitable location that provides adequate
ventilation to maximise cooling. As the amplifier is compact it must be appreciated that adequate time is
allowed for the amplifier to cool down between transmissions especially if used at maximum power. As
ambient temperature, installation location and ventilation are all factors that change for each installation the
user must take this into account. The amplifier may be left in circuit when switched off and the RTX may
be used normally at low power. SSB/FM. This switch when set to SSB adds a small delay before switching
back to RX after a transmission. When using SSB this helps prevent the amplifiers RX TX relay from
constantly switching between RX and TX during pauses in speech as there is no RF carrier to hold the relay
open. In FM/AM modes this is not necessary and the switch position can be set to FM.
ON
OFF
SSB
FM
Red
+
ANTENNA
Specifications:
Freq. Range: 135-175MHz continuous
Power Supply: 12-14Vdc
Max input current 10A
Fuse: 10A
Input Power: 0.5-4W max.
Output Power: 70W max.
www.rmitaly.com info@rmitaly.com
LA144
Black
RTX ANT
RTX
Max 4.0W
Battery / PSU
-
LA144 VHF Amplifier
80
70
60
135MHz
50
40
Power Out (W)
30
20
10
140MHz
145MHz
150MHz
155MHz
160MHz
170MHz
175Mhz
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Power in (W)
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