This amplifier is about as far as you can go using a legal 4w CB radio to drive it - will give around 80w output from 4w input. This model features a 25db receive preamp to boost incoming signals too. On/off switch & power LED. Previously known as RM Model 160P. Will draw around 10amps on transmit.
IMPORTANT : You will need a 90cm connecting lead for the CB-to-amplifier connection - it is important that a 90cm one is used rather than any other length to ensure the SWR that the CB experiences while driving the amps' input is low.
To use this amplifier in a base station, you'll need a power supply like our Hoxin TD-14SS30 30amp Power Supply
Size : 109mm Wide x 125mm Deep x 35mm High
It's worth bearing in mind that the receive amplifier doesn't know the difference between wanted signals and background noise, so although signals will be stronger, the actual signal to noise ratio is largely unchanged. (Example : without preamp you may be receiving a signal at S7 with a background noise of S3, switch the preamp on and the wanted signal increases to S9 but so does the background noise, to S5).
If you get any received interference from wipers, ignition etc, the preamp may even make this worse! (In which case go for the RM Model KL200 which is basically the same amp, just without the receive preamp.)
IMPORTANT NOTES :
- CONSTANT POWER SUPPLY : This amplifier must have power to it all the time it is in line - if you don't want it on just use the on/off switch, but if it is in line it MUST have power to it otherwise the relay will close when the power feed is removed and the transmit power from your CB will not be allowed through, causing damage to both the CB and amplifier.
- AM/SSB SWITCH : This switch should be kept on AM if you are transmitting on AM or FM. The SSB setting is for another mode of transmission where there is not a constant signal transmitted so to avoid the unit constantly switching between receive and transmit with every word, a short delay is introduced, so if you inadvertantly put this switch to SSB when on AM or FM the only thing that will happen is that when you finish transmitting there will be a second or so delay before the unit switches over and allows signals to be received.
- 85W IS THE MAXIMUM YOU CAN GET FROM ANY AMP WITH 4W DRIVE : This is about the highest output you can get from any amplifier when connected to a legal cb with 4w output. There are larger amplifiers available, but these require more power into them, as they have more amplifying transistors. For example : This amp has one main power transistor and it is rated as giving 100w output from 5w input (hence the 80w from 4w input). The larger amplifiers have two or more of these transistors and may be rated at 200w or 400w output but this would be from 10w or 20w input on FM. If anyone tells you they have a 200w or 400w amp but are using it on a 4w CB the chances are they are still only getting 80-85 watts out of it!)
- THESE AMPLIFIERS GET HOT : The majority of the size of these amps are the heat-sink fins on the top - the job of these is to get hot as dissipate the heat into the air, and they will get pretty damn hot in use, especially with a high power amp like the B150. You need to make sure that there is a free flow of air around these amps - best not to cram them into a small space.
- YOU NEED A LOW SWR TO USE AN AMP : One of the quickest ways to kill an amplifier like this is to run it into an antenna system that has a high swr... like the CB's we sell, the output transistor (the bit that can get damaged by a high SWR) is NOT covered by the guarantee as it's the user/installers responsibility to make sure the SWR is low - ideally below 1.5 although you can usually get away with readings upto 1.7 / 1.8 if amplified transmissions are kept short. More about SWR on our SWR explained page.
- INTERNALLY FUSED : This amplifier is fused internally - it has 2x 20mm 10amp fuses, you can buy spares here We advise you also put a fuse in the power lead you use to feed this amp - we will soon be introducing amplifier wiring kits with everything you need but until then, please see or red & black power leads section and our blade fuses & holders.
- BE CAREFULL WHERE YOU USE A HIGH-POWERED AMP LIKE THIS : Please do not use this amplifier is you are within 100 yards of the following : petrol pumps, police/ambulance/fire vehicles or other cb users on the same or adjacent channel to you. You may also find that this amp can set off some older domestic wireless house alarms as well as cause interference/breakthrough on televisions and radios - maybe best switched off when driving through a housing estate for example... leave the amp for the countryside!
- AMPLIFIERS ARE ILLEGAL : Remember Amplifiers like this are illegal to use on CB Radio. A lot of people do use them, and prosecutions are extremely rare and even then only when serious interference or abuse has occured, but please be mindful of their illegality.
- SSB USE : Single Side Band is an illegal mode of transmission that some illegal CB's have... this amplifier can be used on SSB and when used on SSB will take a drive of upto 10w and provide an output of upto 200w peak for that 10w input. Current draw will be around 18-20amps
- A WORD ABOUT HOW INCREASING OUTPUT POWER WORKS : When using an amplifier, double the power does not mean double the transmission distance. For every half a signal point increase at the receiving radio you need to double your power, so the largest gains are made fairly low down the scale :
For Example :
If someone is receving you at signal 5 when you are using 4w, they'd get you at signal 5.5 with 8w, signal 6 with 16w, signal 6.5 with 32w, signal 7 with 64w, signal 7.5 with 128w, signal 8 with 256w etc etc.
So you can see that using this amplifier will give you approximately a 2.25 signal pont increase - however this does rely on their signal meter being calibrated which most aren't really so the actual gains you'll see may differ slightly depending on who you're talking to.
You can also see that if you were running a 250w amplifier, increasing this to 500w will only get you 0.5 signal point increase - the same as going from 4w to 8w !!
Consequently the differences in actual amplification of signal between this amp giving around 85w output and some of the others we sell which give about 50w, is small.
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CB Accessories > Amplifiers