CB Radio Amplifiers are one of the easiest ways to greatly extend the range of your transmitter setup, easy to install and use these power amplifiers will work perfectly if you follow a few simple guidelines.

If your new to CB this post will get you started and go through some of the other things like interference and choice of antenna. We’ll also look at a few simple RF linear amplifiers that economical to run and have a low profile design.

The Basics

RM Italy KL 60 Mobile CW Transmitter

RM Italy KL 60 Mobile Linear Amplifier
Click Picture for Full Details, Customer Reviews and Pricing

A basic CB amplifier will take the 4 watts output from your CB and turn it into 50, 100 or 500 watts of RF power, generally these types of amplifiers give you no control over the amount of output and the only way to reduce it is to put less RF power into the amplifier.

By switching your CB to low power you can usually turn down the power output from the amplifier by a factor of ten.

Some amplifiers will allow you to vary the power by using a control dial but you will pay more for this useful feature.

Before you Start Using a CB RF Amplifier

Make sure your antenna is in good working order before adding an amplifier to your CB setup. Ensure you have good quality antenna coax installed because cheaper coax that will work fine when you are pushing 4 Watts of power through it may not be able to handle 100 Watts.

All branded coax will have its model number printed on the outside of the protective cover at regular intervals, allowing you to see exactly what your using. If your unsure about the particular rating of the coax you already have installed a quick online search with the model number should tell if its suitable for the power output you have planned.

Coax with no markings can mean its of the worst quality and I’d rather change the whole thing before using a linear and take away that unknown factor.

Check the antennas S.W.R (standing wave radio) to make sure there is as little mismatch as possible between CB and antenna by using a S.W.R meter. Putting 100 Watts into a badly matched antenna will cause you a whole load of serious problems and could even shorten or end the life of your shiny new amplifier.

Go over antenna connections and make sure they are clean and in good condition, if your going to invest the time and money installing an amplifier having a healthy antenna system is going to let you get the most out of it.

Increased CB Power and the Law

Many countries will only allow a certain power output from CB radios with the common figure being 4 Watts, by adding an amplifier to your CB you could be breaking the law and face a heavy fine and having your radio equipment confiscated. Sometimes the confiscation is not limited to the piece of equipment that you are using to break the law but can include any transmitting equipment you own.

Please check your local laws before considering installing an amplifier.

Interference

Any powerful transmitted has the potential to interfere with any number of other domestic services with television and radio being the most likely, following the guidelines above and making sure your antenna is working properly with always cut back on the amount of interference your CB will cause to others.

If you are sure that everything is working OK and you still have complaints of interference the best option is to only use the increased power selectively. By only using full power when the services you are causing disruption to are not running or being widely used like the early hours of the morning you can keep interference to a minimum.

Unfortunately from our own experience because you have a big honking antenna on the side of you house you will most likely get blamed for every bit of random interference that your neighbors suffer.

Even when only having antennas mounted outside for receiver purposes only we have had regular complaints, our best advice is be polite and try to get to the bottom of the problem. If you can prove its not you or even better fix your neighbors interference problem you will have someone on your side to defend any future complaints.

Powering your Amplifier

Powering your CB and an amplifier off the same power supply will work but don’t expect to get both working to full capacity from a basic 13.8 volt power supply. The current output from the power supply should reflect the RF output of the amplifier and if you can power the amplifier from a separate supply than the CB then all the better.

Your linear can also run nicely from a 12 volt car battery indoors but there’s still the issue of making sure the battery is topped up so you get the most from your CB setup.

Unlike a regulated power supply a battery will lose its maximum current/voltage output quickly when used at the levels a big RF amplifier requires and reducing the overall effectiveness of the linear.

Using your Amplifier Safely

At first glance it doesn’t seem possible to get any injury from using a RF amplifier but there is a real danger of you or someone else suffering from what is called RF burn.

The increased power that you are outputting from your antenna system is still a form of electrical energy and has the ability to give a substantial shock to anybody who comes in contact with the antenna while you are transmitting, with this is mind consider where you place your antenna so that no one can accidental touch it.

At very high frequencies just being near enough to a radiating antenna or in the path of a directional radio signal alone can cause RF burn with out ever having to actually touch any part of the antenna system.

For most of us this wont be a problem as you will want to mount the CB antenna as high as possible and away from obstructions to make the transmitted radio signals as effective as possible.

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20 Responses to CB Radio Amplifiers

  1. Patriot12 says:

    I’m in this situation rite now where I have a 40ft antenna with a 5/8 wave antenna, 3- 8ft radials. Now I have a swr and watt meter. Swr is 1.6 on ch 1 and 1.3 on ch 40. It seems this is as good as the thing will get. I’m in the process of getting a Rm Italy at 200 watts. My main question is can I simply control my power with the Rf gain knob on my radio? And is my swr “good enough”? Any help would be great I have pictures of the rig and work such as radials and rf choke.

    • Carl says:

      Hey Patriot12

      The traditional way to set SWR is get the lowest reading at the center of the band (say ch20), where a typical CB antenna should be tuned to, then see how far it varies at the top and bottom of the range (ch1 and ch40).

      1.3 is OK, but 1.6 with the extra power your adding is a little high. Take some time to go over the antenna and the connections in the coax feed to see if anything can be improved (also the quality of the coax itself).

      You’d be surprised what little can screw with the SWR. If you can get 1.2 (ish) at the center then provided your antenna is designed properly, you’ll be on to a winner.

      Try not to obsess about a 1.1 reading, as in a real world application there’s too many variables to achieve this easily 🙂

      The RM Italy amp will allow some control from the amount of input power you push into it, but not that much. The amp needs a certain amount before it switches on, so anything before 2 watts (as example) isn’t going to drive the amp to a point of operation.

      There will be output control after the amp has ‘started’ to function but its not really going to be that noticeable (the difference between 150 and 200 watts doesn’t work out that much when converted to actual signal strength)

      BTW, there are some amp (I think RM Italy have at least one) with a variable control dial fitted so you have complete control over the power output.

      Really hope this helps

  2. Eric says:

    I have 2 Gray Electronics 150A amps.They were used,along w/2 23ch.w/ssb mobile radios[old ones,lol] I’m wanting to use one in my truck w dual 4ft.fire sticks.I was also wanting to put an inline fuse in the supply harness to protect it.The radio that I would like to use has been peeked/tuned to 18-25 watts output-will this work ? I have no manual for these linears so I don’t know what amperage fuse to use or max.input power on the amp from the cb can be…!

    • Carl says:

      Hi Eric

      Gray Electronics made a range of linear amps and without more detail, its hard to tell if your CB will run them safely. That said 18-25 watts on the input of most RF amplifiers built for CB is most likely too much and could cause damage.

      For the excessive input problem you could use a power limiter like this Zetagi RP2

      Are you sure there’s not a model somewhere on the amp we can work with. Failing that maybe popping the lid and counting the number of big power transistors will help work out the power input.

      Let me know how you get on

  3. Mike says:

    Hi Carl, Again thanks for your valuable information. Thanks for the advice on buying used equipment but I do have a chance to pick up a used Palomar 200 watt amp with Power Unit for about $150.00 from a friend that I talk to and the tech that worked on it says it’s in good shape. Not sure if I want to go the used route but it is an option. Might just want to go new. As to your question about my coax and antenna. I recently replaced my old coax with new RG8x and I bought enough cable and new fittings to make new jumper cables. My antenna is my old A-99. The SWR’s are below 1.0 and I’m talking to friends 15 miles away and another 45 miles (as the crow flies) away but need a little more power for the one that is furthest away. I will be sure to keep you informed and will take a picture when finished. Thanks again for all you help and information. Mike

  4. Mike says:

    Hi Carl, I’m baaaack. I got my Dosy TC3001-P 3 window meter. Really nice setup but much bigger than I thought it would be. I also just got my Zetagi from the UK (only place I could find it) today. Nice piece of equipment and I can reduce my power 1/2 or 1/4 and it works well. I have been looking at amplifiers from 100 to 200 watts. One in particular caught my eye. It’s Italian made. “RM” KL203P 20-30MHz 100/200w Linear Amplifier Burner + PreAmp AM FM SSB CW CB HF on ebay. I’m not really up to speed on amps. I was looking at others like a 200 watt Palomar linear. There are way too many to choose from. I am wondering if you have any suggestions so I can narrow down the choices or are there any CB’s out there that have amps built in? Thanks Mike

    • Carl says:

      Hi Mike, good to see your getting a nice setup together 🙂

      I’d certainly take a Palomar amp over a RM Italy one, they tend to be put together better. Without going down the ham radio route, there isn’t many producers who still make linear amps aimed at the CB market.

      As for CB’s with built in amps in the range of a few hundred watts, its just doesn’t happen (at least not straight from the maker), There are examples of some bigger radios from people like Ham International that have 100 watt+ amps fitted, but generally most CB’s just don’t have the room to fit that kind of mod.

      Please be careful being secondhand amps as it can be a tricky business. There’s always plenty of scope for the seller to say your not using the unit right or have messed with it after you receive it. Study the feedback of the person your buying from and if possibly stick with someone who has a good track record of delivering decent linear amps (maybe seek out a radio shop that sells online).

      Meant to ask in the last comment I sent if you’ve made sure all your coax and antenna are up to the job of carrying extra power. Whacking a few hundred watts through a bad transmission line is just going to be a waste.

      Let me know how you get on and if at all possibly would love to see a picture of the finished setup 🙂

      Carl

  5. Mike says:

    Hi Carl, Thanks for the great information. I will be checking them out and purchasing before I buy the amp. I may have to pay a little more for quality I suspect. thanks again Mike

  6. Mike says:

    Hi Carl, I ordered the Zetagi like you suggested. I have another question. I’m looking for a new SWR/Watt/Mod meter. I presently have a COLT SWR-3 that is old (vintage and I lost the manual) and I don’t think its accurate (even with the radio being turned up) it reads 65 watts on am and over 200 on SB without an amp!?!?! So I am looking at a Dosey 3 meter read out and a Redman. Not sure if you can adjust SWR’s with them like I can with my COLT. Do you have any suggestions? I would like to keep the purchase price below $150.00 if possible. Thanks Mike

    • Carl says:

      Yeah, certainly sounds like your colt meter has seen better days 🙂

      Not sure what sort of wattage you intend to run, but its good to see your being realistic about the price of a SWR meter.

      The Dosy 3 on Redman is a little above your price guide but Redman also do the Dosy TR-1000 (much cheaper). There’s also more basic models like the Redman Cb Stop RM1001S, but Redman haven’t included any power handling information?. It might be worth getting in touch to confirm before you buy.

      You can find a manual for the TR-1000 here http://www.dosy.com/pdf/tr1000.pdf

      Another option for a high power SWR meter is the range produced by MFJ. These are mainly designed for the ham radio market and will work for CB. They were having some problems with build quality and I’m not sure if that has been sorted now.

  7. Mike says:

    Thanks Carl. That is the info that I have been looking for. I’m really glad that I found your site, it is really great. Thanks again for the really fast answer and I’m putting this site on my desktop. You put things in a way that I can even understand. I just put my radio back on line after 17 years of being off the air, so I’m on a re-learning curve. Mike

  8. Mike says:

    Interesting article but I need clarification. I have a Cobra 142 GTL that some years ago had the power turned up and a few extra things done. I’m running an Antron 99 antenna with a D-104 mike. I have a chance (for a good price) to pick up a 200 watt Palomar linear but everything I read tells me that I can only run it if I have 4 watt output because it would over drive it and burn it up. If that is true than is there another amp that I could use. I’m putting out about 12+ watts on AM and about 30+ watts on sideband. Thanks

    • Carl says:

      Hey Mike

      Many of the old Cobra range had the power mod installed over the years and off the top of my head I can’t think of a typical wideband RF amp that will handle that sort of power on the input without causing issues.

      There is a fix (of sorts) if you don’t want to return the rig to a standard configuration.

      By installing something like the Zetagi RP2 you’ll bring the output down to something an amplifier can safety work with.

      Hope this helps

      Carl

  9. david rodiguez says:

    If I use a Italy RM KL-200 Linear on my mobile C.B. ; do I need to convert it to an 11 meter?

    • Carl says:

      The KL-200 is a wide band amplifier and will work either on CB radio frequencies (11 meter) or ham radio frequencies (10 meter), so your just fine the way you are.

      Hope this helps 🙂

  10. G Money says:

    Year ago my neighbor had an old TV set. They had cable tv but because of the antiquated TV the received me over it even though I was only running 4 watts. First make sure you have a quality base antenna (Antron 99) make sure SWR IS GOOD Try. TVI filter on your end also some trap magnetic filters on the coax. You can also make a coil with the coax (5 or 6 coils )nearest the antenna. Tie them,with wire ties. Than offer to buy a TVI filter for your neighbors TV. It might help. BY the way sometimes it’s better to “disguise ” your CB base antenna. If it’s a Big stick type.with no radials You can hide inside a PVC pipe. Make it look like a flag pole. With no one the wiser ..as some wise guy CBrs go out looking to cause you trouble & they looking for your base antenna.

  11. Bruce (Manhattan Kid) says:

    Skidplate…. Is this the “SKIDPLATE from New York??? Upstate New York???

  12. Skidplate says:

    (Unfortunately from our own experience because you have a big honking antenna on the side of you house you will most likely get blamed for every bit of random interference that your neighbors suffer.

    Even when only having antennas mounted outside for receiver purposes only we have had regular complaints, our best advice is be polite and try to get to the bottom of the problem. If you can prove its not you or even better fix your neighbors interference problem you will have someone on your side to defend any future complaints.)

    My neighbour said I’d interfeered with his telly which he watches sky apparently I was turning his tv off at night , leaving a message on screen that it was going to switch off .

    • rizzer says:

      Hi Skidplate

      Really?, Ive Come across some weird results from RF interference before but this sounds a little bit too specific.

      Not sure if you have this situation solved but there are a few things I would have done to disprove your radio setup is causing the problem.

      1. Ask you neighbour to give a more detailed description of the screen message to understand exactly why their TV feels the need to shut down. It could just be a simple matter of the Sky box updating (as they do sometimes early in the morning) or some timer setting on the TV itself.

      2. Further to point 1, ask yourself why this is only happening at night? Is this because that,s the only time their TV is on or do you increase RF power output after a certain time.

      3. If your neighbour is less the cooperative with more details tell them your going run some tests on your radios over a period of say 2 weeks and could they please report any problems with the TV straight away. During these 2 weeks just switch off your rig and stop using it, leaving no possibility of interference. If they come knocking on your door when your not transmitting then you can confidently tell them that your not the problem and that they should be looking elsewhere for a solution.

      I know its hard sometimes but try to stay polite and focused on getting to the root of the problem as I strongly suspect this interference has nothing to do with you and with a bit of investigation can be sorted out.

      Please let me know how you get on.

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