UHF 400-470MHz Full Band FM/AM/SSB Walkie Talkie Power Amplifier 10W-80W Power Level Selectable VSWR Display 13.8V 15A Input
Photos:
Features:
| Mode | Color | Type | Blink | Function |
| Power measurement | Green | Bar-graph | No | Measurement output power, 10W increments |
| Power setting display | Green | Bar-graph | Yes | Indicates actual power limit (10,20……70，80Watt） |
| SWR measurement | Green | Dot | No* | Shows VSWR |
| Error indicator | Red | Dot(s) | No | Indicate error condition |
*Blinks on under/over range
Push buttons function
| Name | Function |
| RX LNA | Toggles operation of receiver pre-amplifier(LNA) |
| TX PA | Toggles operation of transmit power amplifier |
| SSB ON | Toggles SSB mode |
| SET POWER | Displays/changes transmit power limit |
| SHOW SWR | Enables SWR display |
Turning amplifier on and off
Transmit power amplifier and receiver preamplifier functions are independent on each other . They can be toggled on/offby pressing respective pushbuttons : RX LNA and TX PA . When function is enabled , LED associated with pushbutton is lit .
Amplifier is completely off , when both LEDs are dark .
Changing power level
Transmit power amplifier is equipped with Automatic Level Control loop (ALC).Preset power is adjustable is 8 steps:10W, 20W 30W,40W,50W,60W,70W,80W.Firstpress of SET POWER button enters power setting mode. Multi-function display barblinks, showing preset power level. First press of SET POWER button, doesn’tchange the level, but displays actual setting.Subsequent pressing of SET POWERbutton change power setting. Amplifier exits power setting mode ifSET POWERbutton is not pressed again within 2 seconds.
Automatic Level Control is of saturated nonlinear type, only suitable for FMmodulation. While using amplifier with AM/SSB modulations, set ALC threshold tomaximum power (50W), then adjust transceiver power to yield appropriate powerdisplayed on bar-graph. For AM modulation, carrier power should not exceed 10-15w,to accommodate modulation peaks withoutdistortion.
In case of SSB modulation, observe bar-graph which is ofPEP type, keeping 50WLED lit only occasionally.
Turning SSB mode on/off
The SSB ON button toggles SSB mode on/off, actual state indicated by associatedLED. When SSB mode is enabled, carrier sensing algorithm, time delays, powermeter bar behaviour are changed to address modulation properties. There is no
difference in power amplifier biasing itself, since this modern design is inherentlylinear, unlike elder bipolar transistor based designs.
Using external PTT input
The external PTT (“external keying”) mini jack socket is located on the rear panel. Itallows the TX mode to be enabled by shorting the center conductor of the plug to theouter conductor (to ground). First, enable the TX PA function, by pressing the TX PAbutton. The associated LED will light up. Upon the first shorting of the external PTT,the amplifier enters external PTT mode of operation. The associated LED will startblinking.
In external PTT mode, the amplifier no longer reacts to the RF input signal from thetransceiver. Instead, it goes into TX mode every time the external PTT signal hasbeen applied. Once the SSB mode is enabled, the TX/RX transition delays remainshort. Power meter operates in the PEP mode.
The amplifier remains in the external PTT mode, until the TX PA button is pressed orthe DC power is removed.
Measuring VSWR
This useful function allows to accurately measure amplifier load VSWR.To enableVSWR measurement, press SHOW SWRbutton while transmitting. This mode willpersist as long as amplifier is in transmit mode. Display returns to normal operation
(power measurement) after releasing transceiver PTT button.
Actual VSWR is represented as single”moving dot”. Lowest reading is 1.20, belowthis value respective LED starts blinking, indicating underrange. Highest reading is1.90, crossing 2.00 will cause respective LED blinking, indicating overrange.
Built in VSWR meter is of good quality, compensating for detector nonlinearities,what makes measurement result fairly independent on output power. It also offersexceptional directivity, with residual VSWR reading in order of 1.10.
Error Signalling
To signal error in amplifier operation, multi-function display bar LEDs change colorto red. Appearance of any error denies power amplifier transmit operation.
| Error LED | Meaning | Amplifier reaction |
| High SWR | Excessive VSWR (over 2.1) detected. Typically caused by
faulty antenna. |
Deny transmitting, resume
after PTT release |
| OVER DRIVE | Excessive input power(>7Watt) | Deny transmitting, resume after PTT release |
| DC VOLTAGE | DC supply voltage out of permissible range (10.5V to 14.8V) | Deny transmitting, resume
after PTT release and voltage restored |
| HIGH TEMP | Chassis temperature over 60℃ | Deny transmitting, resume
after cooling down |
| PA FAIL | Amplifier electrical failure | Deny transmitting, resume
after PTT release |
| Specifications: Power amplifier | ||||
| Parameter | Min | Typ. | Max | Remarks |
| Frequency range | 400MHZ | 470MHZ | ||
| Maximum output power | 75W | 80W | 85W | ALC limited |
| Input power range | 0.7W | 7W | Between carrier detect and overdrive thresholds | |
| Input power for full output | 3W | 5W | Frequency dependent | |
| Bypass power | 50W | |||
| Harmonics suppression | 63dBc | |||
| Modulation | AM,FM,SSB | |||
| Circuit type | Twin MOSFET, PUSH-PULL | |||
Specification: Receiver preamplifier
| In-band gain | 13dB | 15dB | 15.5dB | 400-470MHZ |
| Noise figure | 2.4dB | 3dB |
Specification: General
| DC Supply voltage | 10.5V | 12.6V | 14.8V | Operation at low end of range may not yield specified maximum power |
| Transmit supply current | 12A | 13A | Transmitting at maximum power. Frequency dependent | |
| Standby supply current | 20mA | All functions OFF | ||
| 35mA | TX功enable | |||
| 80mA | RX LNA enable | |||
| 88mA | TX PA & RX LNA enable | |||
| RF connector | N-Type connector | |||
| Size | 50H*125W*210L mm | |||
Each Package Contains:
1× Power Amplifier 80U
1× Power Cable
1× RF Connection Cable
1× User Manual
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