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Attention: 

 

The use of Linear Amplifiers are controlled by specific laws wi-
thin the country of use.  These laws must be known to the user 
and are entirely the responsibility of the user. The manufacturer 
declines any responsibility from unlawful use. 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Warranty: 

 

This product is covered by a 24 month warranty commencing from the date of purchase. 
The original purchase receipt will be required for any claim. This warranty does not cov-
er aesthetic damage or damage to the RF power transistors from incorrect use. 
 

KL503  

HF 25—30 MHz Linear Amplifier

 

WARNING: 

Before using this product please read carefully 

all of the information in this manual or at least the quick start guide!!! To 
avoid damage or incorrect operation this is extremely important!!! 

Specifications: 

  
Operation Frequency:  

 

 

25—30 MHz (10m Amateur HF Bands) 

Modulation Types:    

 

 

SSB,CW,AM, FM, (All narrowband modes) 

Transistor: 

 

 

 

 

8x RM 3 1x RM 4 MOSFET  

Max I/P Current: 

 

 

 

32A  

Power Supply:  

 

 

 

13.8VDC+/- 1V 40A 

Input Fuse (Internal): 

 

 

3x10A (Auto Fuse) 

Input RF Power:  

 

 

 

1-6W max (All modes) 

Output RF Power: 

 

 

 

300W max  

Maximum bypass power (Amplifier off):  50W max 
Input VSWR:  

 

 

 

1.1—1.5:1 

Ver 2.0 Feb. 2021 

Summary of Contents for KL503

Page 1: ...ge to the RF power transistors from incorrect use KL503 HF 25 30 MHz Linear Amplifier WARNING Before using this product please read carefully all of the information in this manual or at least the quick start guide To avoid damage or incorrect operation this is extremely important Specifications Operation Frequency 25 30 MHz 10m Amateur HF Bands Modulation Types SSB CW AM FM All narrowband modes Tr...

Page 2: ...ble 13 8VDC 1V 40A Power Supply or Auto Battery Pay attention to the correct polarity 4 Make sure that the amplifier is switched off 5 Adjust the Transceivers RF output power to 5W 6W max if it is capable of more than 5W output 6 Switch on the Amplifier and start operating 7 Check that the antenna VSWR is acceptable with the amplifier in use Any large increase in VSWR indicates that the Antenna is...

Page 3: ...ceive Pre Amplifier ON OFF Switch 3 Amplifier ON OFF Switch 4 TX indicator LED 5 Pre Amplifier ON LED 6 Amplifier ON LED 7 Input Attenuator 1 RTX SO239 RF input connector 2 DC Input power connector Polarity is marked on the supplied mat ing connector 3 ANT RF Output SO239 Socket to Antenna ...

Page 4: ...switch should be set to SSB This adds a short delay to the release time of the RTX relays so that pauses in speech do not cause the RTX relay to drop out In AM or FM mode the SSB delay switch should be set to AM The amplifier must be connected via the input power connector to a suitable power sup ply of the correct voltage output and sufficient current rating The output should be 13 6 13 8V DC but...

Page 5: ...t Before the amplifier is switched on switch the power output of the drive radio should be adjusted correctly if it is capable of outputting a power greater than 6W This may be done with the amplifier connected but switched off 6W is the maximum permissible in put power to the amplifier but approximately 4 5W input should be sufficient to realise full output and an input power of 1 5W is OK as it ...

Page 6: ...n a few minutes should be avoided to avoid ex cessive transistor junction temperature The exact time for transmission in these modes will depend on numerous factors such as how good the ventilation around the amplifier is if there is sufficient space for freely flowing air to circulate etc If the ambient temper ature is high this will reduce the total time in transmission Common sense should be In...

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