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AR305 300 WATT 10-175 MHZ AMPLIFIER
This amplifier design covers frequencies from HF to VHF with a power output
level of 300 watts using RF power
MOSFETs. The MRF151G used in this design is considered as a state of the art
device. The MRF151G is housed in
a special push-pull header commonly known as "Gemini" (twins) meaning that there
are two identical transistors
mounted next to each other on a common carrier or flange. This amplifier was
originally designed for operation
from a constant 40 to 50 volt power supply. The frequency range of this
amplifier design is 10-175 MHz. As the
MRF151G is basically made for operation from a 50 volt supply, lowering the
voltage down to 40 volts would make
the unit almost indestructible against load mismatches such as open coax or a
broken antenna. This amplifier
design was featured in MICROWAVES and RF (November 1987) magazine.
SPECIFICATIONS:
| Frequency Range |
10-175 MHz |
| Power Input |
15 watts (typical) |
| Power Output |
300 watts (typical) |
| Input Impedance |
50 ohms |
| Output Impedance |
50 ohms |
| Input Voltage |
40-50 volts DC |
| Input Current |
12-15 amps (typical) |
| R1 - 1k Ohm, 1/2 W |
R8, R9 - 50 Ohm Microwave Power
Resistor |
L1 - 10 Turns AWG #16 Enameled
Wire |
| R2 - 1.5k Ohm, 1/2 W |
C1, C9 - ARCO 404, 8-60 pF
Compression Mica |
L2 - Ferrite Beads over AWG #16
Wire |
| R3 - 1.5k Ohm, 2 W |
C2 - 130 pF Ceramic Chip |
L3, L4 - Lead Lengths of R8 and
R9 |
| R4 - 1k Trimpot |
C3, C10, C11 - 0.1 uF Ceramic
Chip |
FET - MRF151G |
| R5 - 6.8k Ohm, 1/4 W |
C4, C5, C12 - 1000 pF Ceramic
Chip |
T1 - 9:1 RF Transformer |
| R6 - Thermistor, 10K at 25 degC
2.5k at 75 deg C |
C6, C7 - 5000 pF Ceramic Chip |
T2 - 1:4 RF Transformer |
| R7 - 2k Ohm, 1/2 W |
C8 - 0.47 uF Ceramic Chip |
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Printed Circuit Boards and
Components Available
The above is a summary description of an HF amplifier described in the
MOTOROLA Engineering Bulletins and Application Notes.
These Engineering Bulletins and Application Notes may be obtained from your
local MOTOROLA office or can be found in the
MOTOROLA RF DEVICE DATA MANUAL. These amplifiers have been designed and tested
by engineers at Motorola.
COMPONENT SETS FOR AR305
| Capacitor Set |
$ 29.50 |
| 1 ea. |
130pf ATC Cer Chip
Cap |
| 3 ea. |
1000pf ATC Cer Chip
Cap |
| 2 ea. |
5000pf ATC Cer Chip
Cap |
| 3 ea. |
0.1uf Cer Chip Cap |
| 1 ea. |
0.47uf Cer Chip Cap |
| 2 ea. |
ARCO 404, 8-60pf |
| Resistor Set |
$ 35.95 |
| 1 ea. |
6.8K ohm 1/4 watt |
| 1 ea. |
8.2K ohm 1/4 watt |
| 1 ea. |
1K ohm 1/2 watt |
| 1 ea. |
1.5K ohm 1/2 watt |
| 1 ea. |
2K ohm 1/2 watt |
| 1 ea. |
1.5K ohm 2 watt |
| 2 ea. |
50 ohm 20 watt Flange Mtg. |
| 1 ea. |
1K ohm Trimpot |
| 1 ea. |
10K(25C)-2.5K(75C) Thermistor |
| Ferrite Set |
$ 2.75 |
| 1 ea. |
Balun |
| 1 ea. |
16" AWG #16 Enameled Wire |
| 1 ea. |
12" AWG #16 Teflon Insulated
wire |
| Transformer Set |
$ 55.95 |
| 1 ea. |
T1 - 9:1 RF Transformer |
| 1 ea. |
T2 - 1:4 RF Transformer |
| Printed Circuit Board
Set (2) |
$ 23.00 |
| 1N5923A 8.2 Volt
Zener |
$ 1.40 |
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This Page was last
updated September 30, 2005
