OK - now that we have selected the antenna, radio, coax, SWR meter & jumper coax, and mic - we are ready to get a power supply for a base station setup. That is - if we are using a mobile radio for a base radio. We will also discuss installing a CB in your vehicle. If you are new to radio or have wanted to explore it - this is for you...
Previous related threads - read first if you haven't already:
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-1-a.html
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-2-a.html
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-3-a.html
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-4-a.html
Used CB Radio: How to Buy-Part 5:
Power Supplies...
Mobile radios are rated at 12v DC. But that is just a generic thing to say; it isn't operating at 12v. In reality, it will be running at 13.8v to 14.1v. Which is the typical voltage of a car's electrical system. Typically, the radio will run best at 13.8v. Most power supplies that claim they are 12v DC are actually putting out 13.8v; this is what you need to make any mobile radio work as a base station radio. But the amperage or 'amps' that it supplies is how any power supply will be rated - is also an important consideration. We will get to that in a moment. The price of any given power supply will go up as the amperage it is capable of providing is increased. If you need a 10 amp supply; then the price should be around $60. A 20 amp supply will cost about $120; and so on. A 10 amp supply is probably be all that you will need for any CB or export radio if you don't plan to use a linear amp. If you are going to run a linear amp on your station in the future; then buying a larger power supply to fill the needs of the radio and the amp - should be considered at this time.
The brands are: Micronta ('Radio Shack'), Antron, Pyramid, and Samlex. To name a just a few of the more common/available ones. Some of the Antron and Pyramid power supplies have an adjustable voltage output. You can turn the voltage up to 14.1v or more; but it is not recommended to do that. Radio life expectancy will decrease if pushed with too many volts all of the time. Then it will need to be repaired or replaced; and who wants to do that after all the time and money has been invested? The gain of using too much voltage is small - and isn't a wise decision...
How much power supply is needed - if a radio draws only a few amps when transmitting? As a rule, most mobile radios (either a stock CB, SSB CB, or an export radio) will draw no more than 6 amps when transmitting. CB's will use less than an export radio - up to 3-3 1/2 amps. So you will need a 10 amp supply for an export radio and a 5 amp supply for a CB. Why 10 amps - and not 6 for the export radio? Or a 4 amp supply for the CB? Because it will run cooler and last longer when it is not being forced to run at its designed limit. Power supplies will also have a voltage drop and fall below the desired 13.8v when running at the amperage limit. Radios like a comfortable environment of no more than 13.8v - or no less that 12.8 when transmitting. If your supply isn't providing these requirements; it may be time to get a bigger supply...
As mentioned before, if you are going to run a linear amp with your system, one needs to keep in mind a few 'rules of thumb'. Always get a power supply that is rated higher than the amp will require - for the same reasons mentioned above. Make sure there is enough air flow around it - and blow the dust out of it every so often. A 100 watt amplifier will need a 13 amp supply - plus the amount that the CB radio needs. So, a 20 amp supply should be the choice. If running a 300 watt amplifier with an export radio; then it will need 35 amps - plus the export radios needs. So, a 45 amp supply should be the proper choice. This will ensure that voltages won't drop and the power supply won't be over-taxed and overheat and become damaged. If you are using an AC powered base radio that has a built-in power supply; then just get the right power supply for the amplifier.
Of course, linear amps are illegal for CB operators. They are often intended and sold to license holding Ham operators for the 10 meter band (28.300-28.500mhz). But those CB operators that do run them - use these same procedures when choosing the right power supply. Running a linear has some specific requirements than just the power supply alone. Linear amplifiers will be discussed in greater detail in another episode to come. So, stay tuned...
Many AC powered base station radios with internal power supplies - also come equipped with a 12v DC external plug on the back of the radio and a AC/DC switch - so that it can be switched from AC use to DC use with an external supply. This is also a consideration - as the built-in power supplies can be weak and/or noisy. I have seen improvements in transmitting when using an external supply using this method. Sometimes the receive is also quieter too; because many external fully-regulated power supplies have additional filtering. I know that you have probably heard this expression before: "crap in; crap out..." So, having a clean operating power supply is an important consideration for any base station.
Here is a site that sells power supplies new. They have a pretty fair spread of brands and common available amperages - to use as a reference.
http://www.wearecb.com/store/12-volt-power-supply-c-31_77.html
Used power supplies can be had on eBay for 2/3 of original list prices. Sometimes less. They may cost a bit to ship - because they aren't exactly light weight (the power transformers can be as much as 30 pounds in the larger power supplies!). Consider that in the cost. If you can get one locally, I would do that and save money. Check out the supply before you get it - so that it isn't noisy (when hooking up a radio to the supply; be sure that there isn't a 'zzzz' hum-could be a leaky cap and repairs may be necessary...I would pass on buying it...). Older power supplies can get noisy; regadless if they are built in the radio - or a stand-alone unit. Buyer beware! If in doubt; buy a new one.
Setting up a Mobile CB Radio...
One would want to find a location to mount the radio that can be seen conveniently - that doesn't obscure your vision to anything important. If your radio came with a mounting bracket and mounting knobs, you are ready to proceed. You will need a drill, 1/4 inch bolts/nuts, and some 1/4 in flat washers (3/4-1 in outer dia). Tape the bracket (w/o the radio) where you want to mount it - probably just under the bottom edge of the dashboard. Mark the two holes thru the bracket that are to be the mounting holes - with a felt pen. Remove bracket/tape; drill hole with 1/4 in drill. Be sure before drilling that you don't drill thru any wiring or anything important! Bolt bracket into place - using the flat washers on the inside area of the dash. Now, mount the radio on the bracket with the mounting knobs/screws. Another option to drilling and maiming ones car - is the 'Sawtooth CB Mount' (I use one!) - found here:
http://www.walcottcb.com/workman-c520-saw-tooth-hump-mount-p-1115.html
Wiring the radio is best accomplished by running 12 ga wire thru a rubber grommet on the firewall of the vehicle. Buy some red and black wire - about 8 ft in length each (Or just splice in enough red and black wire to make up for the length of wire that came with the radio). Route the wire carefully inside the engine compartment - so that it doesn't touch anything that might melt the wire and short - causing a fire! Use some nylon zip-ties every 1 1/2 feet to secure its route - too. Crimp a wire lug that will fit thru the bolts on the "+" battery clamp and tighten it down. Now crimp a wire connector to the other end of the same red wire and join it to the radio's power plug/wire (there should be a fuse on that wire). Do the same thing for the black wire as you just did for the red wire and hook it to the "-" battery bolt clamp (make sure that you have disconnected the "+" cable from the car battery before you start this whole procedure). Now plug the power plug into the back of the radio. Red wire should be running from the "+" battery post to the red wire that goes into the radio. Same for the "-" black wire from the radio to the "-" battery post. Failure to do this properly will cause damage to your radio! SO - pay attention!. Plug the mic in. Don't turn anything on yet...you must now hook up the antenna. NEVER transmit on your radio w/o the antenna mounted and the SWR calibrated!.
You can use a cigarette lighter/plug for a CB/export radio if you don't want to hardwire directly to the battery (the cigarette lighter is on a 20 amp circuit). The center of that plug is the "+" and it should have a red wire go to that point. But if you are planning to use a linear amp - NEVER use the cigarette lighter power plug. It will draw too many amps and blow fuses. If you replace the fuse with a larger one - YOU MAY CAUSE AN ELECTRICAL FIRE FROM OVERHEATING THAT SUPPLY CIRCUIT!!! Make sure there is a fuse in-line from the "+" battery side to the radio. Most radios come with a fused line. Use it! If it doesn't have one; get one from an auto supply house and splice one in. When the radio is hooked up directly to the battery, it will operate when the car is shut off. SO - keep this in mind and be sure that the radio is off when exiting the vehicle. Or you will run your battery down and get stuck somewhere...
I'm going to assume that you have a magnet mount antenna for the vehicle. If you are using a different type of antenna; then become a member and we can discuss how to mount the antenna that you have. Installing a permanent mount antenna can have advantages; but you will be drilling or cutting into the vehicles sheet metal! So one must be aware of the procedure and follow it carefully if you choose this route. I also think mag mounts are easy to take off and put back on with little difficulty...
Place the magnet mount on the top/center of the vehicle. Route the cable thru a window or door - and secure in a way that doesn't interfere with leaving or entering the vehicle. Run the coax under the floor/carpet once it is in the vehicle twards the radio. Route the cable in such a way as to use up the entire length w/o looping the coax over itself. You should have just enough left to reach the back of the radio. Screw the PL-259 connector in the back of the radio. Are we finished yet? No; but you have made all of the necessary moves except for one more. Now; the SWR must be adjusted before you can transmit ANYTHING!!!
How to do that? Found here:
SWR
Once this is calibrated; you are done!
If you might have any questions or problems, it is free to join the WWRF and only takes a minute or so.
Disclaimer: Not responsible for installation or damage. Owner assumes all responsibility for work done. This is only meant as a guideline. If in doubt, ask an experienced friend to help you out...
Bookmark this page - if it has been helpful to you...
Previous related threads - read first if you haven't already:
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-1-a.html
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-2-a.html
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-3-a.html
http://www.worldwidedx.com/general-...tizens-band-radio-radio-how-buy-part-4-a.html
Used CB Radio: How to Buy-Part 5:
Power Supplies...
Mobile radios are rated at 12v DC. But that is just a generic thing to say; it isn't operating at 12v. In reality, it will be running at 13.8v to 14.1v. Which is the typical voltage of a car's electrical system. Typically, the radio will run best at 13.8v. Most power supplies that claim they are 12v DC are actually putting out 13.8v; this is what you need to make any mobile radio work as a base station radio. But the amperage or 'amps' that it supplies is how any power supply will be rated - is also an important consideration. We will get to that in a moment. The price of any given power supply will go up as the amperage it is capable of providing is increased. If you need a 10 amp supply; then the price should be around $60. A 20 amp supply will cost about $120; and so on. A 10 amp supply is probably be all that you will need for any CB or export radio if you don't plan to use a linear amp. If you are going to run a linear amp on your station in the future; then buying a larger power supply to fill the needs of the radio and the amp - should be considered at this time.
The brands are: Micronta ('Radio Shack'), Antron, Pyramid, and Samlex. To name a just a few of the more common/available ones. Some of the Antron and Pyramid power supplies have an adjustable voltage output. You can turn the voltage up to 14.1v or more; but it is not recommended to do that. Radio life expectancy will decrease if pushed with too many volts all of the time. Then it will need to be repaired or replaced; and who wants to do that after all the time and money has been invested? The gain of using too much voltage is small - and isn't a wise decision...
How much power supply is needed - if a radio draws only a few amps when transmitting? As a rule, most mobile radios (either a stock CB, SSB CB, or an export radio) will draw no more than 6 amps when transmitting. CB's will use less than an export radio - up to 3-3 1/2 amps. So you will need a 10 amp supply for an export radio and a 5 amp supply for a CB. Why 10 amps - and not 6 for the export radio? Or a 4 amp supply for the CB? Because it will run cooler and last longer when it is not being forced to run at its designed limit. Power supplies will also have a voltage drop and fall below the desired 13.8v when running at the amperage limit. Radios like a comfortable environment of no more than 13.8v - or no less that 12.8 when transmitting. If your supply isn't providing these requirements; it may be time to get a bigger supply...
As mentioned before, if you are going to run a linear amp with your system, one needs to keep in mind a few 'rules of thumb'. Always get a power supply that is rated higher than the amp will require - for the same reasons mentioned above. Make sure there is enough air flow around it - and blow the dust out of it every so often. A 100 watt amplifier will need a 13 amp supply - plus the amount that the CB radio needs. So, a 20 amp supply should be the choice. If running a 300 watt amplifier with an export radio; then it will need 35 amps - plus the export radios needs. So, a 45 amp supply should be the proper choice. This will ensure that voltages won't drop and the power supply won't be over-taxed and overheat and become damaged. If you are using an AC powered base radio that has a built-in power supply; then just get the right power supply for the amplifier.
Of course, linear amps are illegal for CB operators. They are often intended and sold to license holding Ham operators for the 10 meter band (28.300-28.500mhz). But those CB operators that do run them - use these same procedures when choosing the right power supply. Running a linear has some specific requirements than just the power supply alone. Linear amplifiers will be discussed in greater detail in another episode to come. So, stay tuned...
Many AC powered base station radios with internal power supplies - also come equipped with a 12v DC external plug on the back of the radio and a AC/DC switch - so that it can be switched from AC use to DC use with an external supply. This is also a consideration - as the built-in power supplies can be weak and/or noisy. I have seen improvements in transmitting when using an external supply using this method. Sometimes the receive is also quieter too; because many external fully-regulated power supplies have additional filtering. I know that you have probably heard this expression before: "crap in; crap out..." So, having a clean operating power supply is an important consideration for any base station.
Here is a site that sells power supplies new. They have a pretty fair spread of brands and common available amperages - to use as a reference.
http://www.wearecb.com/store/12-volt-power-supply-c-31_77.html
Used power supplies can be had on eBay for 2/3 of original list prices. Sometimes less. They may cost a bit to ship - because they aren't exactly light weight (the power transformers can be as much as 30 pounds in the larger power supplies!). Consider that in the cost. If you can get one locally, I would do that and save money. Check out the supply before you get it - so that it isn't noisy (when hooking up a radio to the supply; be sure that there isn't a 'zzzz' hum-could be a leaky cap and repairs may be necessary...I would pass on buying it...). Older power supplies can get noisy; regadless if they are built in the radio - or a stand-alone unit. Buyer beware! If in doubt; buy a new one.
Setting up a Mobile CB Radio...
One would want to find a location to mount the radio that can be seen conveniently - that doesn't obscure your vision to anything important. If your radio came with a mounting bracket and mounting knobs, you are ready to proceed. You will need a drill, 1/4 inch bolts/nuts, and some 1/4 in flat washers (3/4-1 in outer dia). Tape the bracket (w/o the radio) where you want to mount it - probably just under the bottom edge of the dashboard. Mark the two holes thru the bracket that are to be the mounting holes - with a felt pen. Remove bracket/tape; drill hole with 1/4 in drill. Be sure before drilling that you don't drill thru any wiring or anything important! Bolt bracket into place - using the flat washers on the inside area of the dash. Now, mount the radio on the bracket with the mounting knobs/screws. Another option to drilling and maiming ones car - is the 'Sawtooth CB Mount' (I use one!) - found here:
http://www.walcottcb.com/workman-c520-saw-tooth-hump-mount-p-1115.html
Wiring the radio is best accomplished by running 12 ga wire thru a rubber grommet on the firewall of the vehicle. Buy some red and black wire - about 8 ft in length each (Or just splice in enough red and black wire to make up for the length of wire that came with the radio). Route the wire carefully inside the engine compartment - so that it doesn't touch anything that might melt the wire and short - causing a fire! Use some nylon zip-ties every 1 1/2 feet to secure its route - too. Crimp a wire lug that will fit thru the bolts on the "+" battery clamp and tighten it down. Now crimp a wire connector to the other end of the same red wire and join it to the radio's power plug/wire (there should be a fuse on that wire). Do the same thing for the black wire as you just did for the red wire and hook it to the "-" battery bolt clamp (make sure that you have disconnected the "+" cable from the car battery before you start this whole procedure). Now plug the power plug into the back of the radio. Red wire should be running from the "+" battery post to the red wire that goes into the radio. Same for the "-" black wire from the radio to the "-" battery post. Failure to do this properly will cause damage to your radio! SO - pay attention!. Plug the mic in. Don't turn anything on yet...you must now hook up the antenna. NEVER transmit on your radio w/o the antenna mounted and the SWR calibrated!.
You can use a cigarette lighter/plug for a CB/export radio if you don't want to hardwire directly to the battery (the cigarette lighter is on a 20 amp circuit). The center of that plug is the "+" and it should have a red wire go to that point. But if you are planning to use a linear amp - NEVER use the cigarette lighter power plug. It will draw too many amps and blow fuses. If you replace the fuse with a larger one - YOU MAY CAUSE AN ELECTRICAL FIRE FROM OVERHEATING THAT SUPPLY CIRCUIT!!! Make sure there is a fuse in-line from the "+" battery side to the radio. Most radios come with a fused line. Use it! If it doesn't have one; get one from an auto supply house and splice one in. When the radio is hooked up directly to the battery, it will operate when the car is shut off. SO - keep this in mind and be sure that the radio is off when exiting the vehicle. Or you will run your battery down and get stuck somewhere...
I'm going to assume that you have a magnet mount antenna for the vehicle. If you are using a different type of antenna; then become a member and we can discuss how to mount the antenna that you have. Installing a permanent mount antenna can have advantages; but you will be drilling or cutting into the vehicles sheet metal! So one must be aware of the procedure and follow it carefully if you choose this route. I also think mag mounts are easy to take off and put back on with little difficulty...
Place the magnet mount on the top/center of the vehicle. Route the cable thru a window or door - and secure in a way that doesn't interfere with leaving or entering the vehicle. Run the coax under the floor/carpet once it is in the vehicle twards the radio. Route the cable in such a way as to use up the entire length w/o looping the coax over itself. You should have just enough left to reach the back of the radio. Screw the PL-259 connector in the back of the radio. Are we finished yet? No; but you have made all of the necessary moves except for one more. Now; the SWR must be adjusted before you can transmit ANYTHING!!!
How to do that? Found here:
SWR
Once this is calibrated; you are done!
If you might have any questions or problems, it is free to join the WWRF and only takes a minute or so.
Disclaimer: Not responsible for installation or damage. Owner assumes all responsibility for work done. This is only meant as a guideline. If in doubt, ask an experienced friend to help you out...
Bookmark this page - if it has been helpful to you...
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