RM KL203 Amplifier Review

I spent 10 years in the CB radio hobby before ever purchasing an amplifier. I found that in most cases I was able to talk to all the locals and DX without the use of one.

Then one day I was having trouble talking to a local friend because there was a lot of skip interference and decided I would purchase an amplifier. I won’t get into a discussion on legality of using an amplifier (they are illegal for use with a CB) but all I will say is that if used properly and without harmful intent to cause interference an amplifier can be an excellent addition to your CB collection.

Buying an amplifier can be a confusing process. Because they are illegal for CB use many shops don’t display them in cases. There are 100’s of different models and brands floating around out there and it can be tough to choose the right one.

That’s why I love the KL203 from RM ITALY. It’s the perfect amplifier for most beginners and works great for seasoned veterans as well. It’s one of the smallest and cheapest amplifiers available but it works and is durable and reliable.

I purchased mine for $64.99 on ebay + shipping costs of around $10. It arrived in a small white box with a short instruction manual which isn’t much use.

The unit is small – it can easily be held in one hand and is light. The housing is a mix of plastic and the metal cooling fins. It’s a basic unit with only two switches on the front – a ON/OFF switch and a SSB/AM switch. There is a red LED that lets you know when the power to the unit is on.

The rear of the unit has the two coax connectors – one for your antenna and one for the transmitter.

The negative and positive power cords come out of the back of the unit for easy hookup – the wire isn’t a very large gauge and I would recommend using a larger size wire for hookup, especially if you have to run a longer section of wire to the battery.

The unit has an internal fuse protection (so if yours ever doesn’t power up you may want to check the fuse).

These particular amplifiers are factory rated for an input from the transmitter in the range of 0.5 watts – 10 watts on AM and 1 watt to 20 watts on SSB. Although these are the factory specifications a number of us who have owned these amplifiers have found that they perform best with a low deadkey input from the transmitter.

If you plan to use one of these my personal suggestion would be to run a 1 – 1 1/2 watt deadkey maximum. This will keep the amp cool and will help extend the life of the amp. Many people add small fans to these amps to keep them cool.

In most cases for output you will see around 100-120 watts output on AM and 140-160 watts output on SSB. You could possibly see more by really overdriving this little amp but that wouldn’t really be worth it. These numbers are pretty typical for output in most installs.

Although fairly cheap in design and price – these amps sound very nice on the air and don’t add a lot of distortion to your signal unless they are overdriven. When overdriven they tend to create a lot of RF which you might pick up in your car speakers or if used in a base install you may get RF in speakers, phones..etc. But you can’t really blame the amp for this – a dirty signal in = a dirty signal out.

These amps use (4) Mosfet RM3 transistors to make their power output. I’ve found them to be very reliable and of the 4 versions I’ve owned of these amps from RM Italy I’ve yet to have one stop working or have any blown components.

Most beginners aren’t looking to win a keydown competition, they just want to get their signal out a little farther and that’s why the KL203 is a great amplifier for giving your signal a boost.

Low in price, easy to hookup, and great performance. A very nice overall package.


RM KL-203 MOSFET Linear Amplifier.

  • 0.5W – 10W AM/FM, 1 – 20W SSB input
  • Up to 100W AM/FM 200W SSB output
  • 13.8V DC
  • Switchable SSB Delay Relay
Frequency 18-30 MHz (Europe)
Supply 12-14 Vcc
Input energy/power 10 A
Input power 0,5-10 W
Input power SSB 1-20 W
Output power 100 W Max
Output power SSB 200 W pep Max
Fuse 12 A
Output power level
Size 109x125x35 mm
Weight 325 gr.


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