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307
| | Posted on Friday, November 30, 2001 - 9:38 pm: | 
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Something about POWER
If you have lights that dim on your radio when you are in the transmit mode then this article is for you . Allot of the times when a radio is peaked for performance , there is one thing that is overlooked about 99.9 percent of the time .....The size of the POWER WIRES that go into the radio . Generally speaking as I was doing performance enhancements to radios I noticed that after I was complete and I powered up the radio and transmitted that several of the lights on the front of the radio would "DIM" as I spoke into the microphone after re-installing the radio back into the vehicle .
The reason that this happens is because the radio before it was tuned up pulled just the right amount of current at the time but when you took your radio to have it peaked up . After the peak out the radio pulls more current than most small power cables can supply . When this happens the voltage at the battery or power source is one voltage and at the other end where it plugs into the radio , it is another voltage . The terminology for this is called "VOLTAGE DROP" . It is simple when looking at it from a plumbers standpoint . If you need a gallon of water fast you would try to suck it through a straw that you drink soda through ? You may consider using a garden hose instead . The same principal applies towards current in a wire . The more current that you need to operate the radio , the thicker the power wires need to be to deliver the amount of current that the radio needs to operate at it's full potential .
I have seen radios that perform well over the specification on the bench and when you give It back to the person who owns it , they put it in their car and it will only do about 2/3 rds of what it did on the bench . Come to find out that the power wires are to small .
There is a fast way to tell if the radio's power wires are large enough for the radio or not . Take a volt meter and read the voltage at the source (battery or power supply) , while the radio is in the transmit mode . Then take the same reading on the back of the radio right next to the power connector . The easiest way to do this is to use two stick pins through the insulation . One through the red wire and one through the black wire . Key down the transmitter and measure the voltage at the stick pin point . The voltage difference should not exceed about 250 millivolts or 1/4 of a volt .
If it does , spend the extra 5 bucks on a heavy duty power cord and you will find out that the radio will even put out more power than you expected and guess what ? The lights will no longer dim when you key up the microphone .
"307" |
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