Jump to content

Power Supply For CB Radio? Mod


Corrosion.
 Share

Recommended Posts

I have an old [Realistic One Hander CB Radio]

It runs on about 2-4 amps and 12volts

I have an old power supply from a Dell Optiplex GX1, it has 12volts and 6/8 amps I'd like to power the cb radio with it but I have three problems.

1. The power supply has no switch, it was built into the case, I don't know which two wires will turn it on

2. I don't know if it needs a load

3. I am unsure if it's safe to power the cb radio (It has a cigarette lighter adapter, will that regulate the current?)

I'm currently powering the cb with a 12v/1amp ac/dc pack, I get it to turn on but cannot hear anyone over the radio, so I think its the fact its underpowered is causing it to lose range.

Can you guys help me out?

Link to comment
Share on other sites

If it's an old AT power supple where the power button is a switch that carries all the current of the power supple go buy a multimeter and figure out which of the wires are live and which aren't. At that point paring the wires should be easy but if it isn't then there is a 50 50 chance of you been correct if you guess and even if you get it wrong hilarity will ensue.

If it's a ATX power supply on the other hand get a paper clip and stick it in the green pin and any available black pin.

Link to comment
Share on other sites

Must be an AT because there is no green pin/wire on the supply

EDIT

From wikipedia

Issues with Dell power supplies

Older Dell computers, particularly those from the Pentium II and III times, are notable for using proprietary power wiring on their power supplies and motherboards. While the motherboard connectors appear to be standard ATX, and will actually fit a standard power supply, they are not compatible. Not only have wires been switched from one location to another, but the number of wires for a given voltage has been changed. Thus, the pins cannot simply be rearranged.[2]

Maybe this is why I cannot find the green wire (the dell power supply was for a dell p2 pc)

EDIT

Found the pc and its power supply

http://support.dell.com/support/edocs/syst...hnica.htm#power

Still cannot find anything to tell me what each wire is for or anything to clue which wire I need

(I don't have a volt meter either)

EDIT

OK! So its the gray and black wire....

It's not turning on though.... do I need a load then?

and I'm still unsure if its too much power for the cb radio

Link to comment
Share on other sites

Almost gave myself a heart attack lol. I don't normally work with high voltages like that...

I got it working :) CB 'n all!

Gray wire jumped to gnd - power psu

Yellow wire + gnd - 12V

for anyone who wants to do something similar with a dell psu

Link to comment
Share on other sites

most people know what the colours of standard PSU's are or the basics:

RED: +5V

ORANGE: +3.3V

BLACK: GND

YELLOW: +12V

also Dell and Compaq liked to stray away from the standards slightly.

there are 100's of sites to look at to work this out as well.

as for not having a volt meter. go and buy one. how can you expect to play with electronics and radio without having one? you can get them here for around 10 - 15 $.

now that i have stopped bitching heres some advice.

i did a similar thing about 5 years ago and found i had to use a small switch to turn off the internal fan. otherwise i had a lot of noise from it.

also if you find that when you are transmitting and the lights on you unit go dim or flash try hooking a 12V car battery to the +Ve and -Ve wires to take some of the load. the good thing about this is that when your unit is receiving then the powersupply is charges the battery.

what sort of antenna are you using? you should use one that is tuned. the best formula i have found to find the 1/4 wave length that is good for CB Radios is as follows:

Length = 468/f

where f is frequency and Length is in ft.

so we get:

Length = 468/27

27 is the frequency used in standard CB radios (unless its a UHF CB)

so Length is 17.33ft

this can be arranged in any fashion including just vertical (i used a piece of aluminum tubing close to the size and finished off the length with a coil of wire at the base. base was made of wood ie broom handle)

another is to have it in a 5/8th wavelength. so double the length (so its 1 full wavelength) and divide it by 5/8ths

then cut 5 pieces of aluminum tubing that size. then arrange in this order:

|

|

|

|

|

|

|

|

|

|

/ \

/ \

/ \

/ \

/ \

/ \

there are 4 diagonal poles to be connected to GND for a ground plain. and the center of the coax goes to the vertical pole for the antenna.

hope this helps. and all this stuff i worked out before i found the internet lol.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...