RM KL503 – All Mode 20-30 MHz (250WAM/FM 450 SSB) Amplifier


The RM KL503 is a high-performance, solid state mobile amplifier engineered to boost your radio signals across a 20-30 MHz frequency range.


The RM KL503 is a robust and versatile solid-state mobile amplifier, designed to enhance your radio communications over the 20-30 MHz frequency range. With a formidable output of 250 watts in AM/FM modes and up to 450 watts in SSB mode, this amplifier ensures strong and clear signals, ideal for DX enthusiasts.RM KL503 - All Mode 20-30 MHz (250WAM/FM 450 SSB) Amplifier

It features a six-way output power control that allows for precise adjustments according to varying needs and conditions. Additionally, the RM KL503 is equipped with a low-noise pre-amplifier that improves signal clarity and reception quality.

For added reliability and safety, it includes an electronic switch and inversion polarity protection, guarding the device against potential electrical mishaps. This amplifier is a top choice for amateur radio operators looking to boost their transmission capabilities and achieve superior communication performance.


Frequency20-30 MHz
Supply12-14V CC
Input Energy/Power12-30A
Input Power1-6W
Input Power SSB2-12W
Output Power250W Max
Output Power SSB450W PEP Max
Fuse3 x 10A
Output Power Level6
Size170 x 295 x 62 mm
Weight1.5 kg
Antenna Preamplifier26 dB


Please Note: Do not exceed Input Power – The manufacturer’s RM Italy do not repair any amplifiers that have been over-driven by mistake under warranty and charges are very expensive – If you are unsure please call or email for further details.

Additional information

Weight1.7 kg