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Latest Posts

Topic Author Posted On
power for Kenwood TW-4000A KN6CWJ on 24/8/19
Simple answer is get a power supply that can deliver more current. It is generally a good idea to get one that provides a little overhead as in your case maybe 10 amps. Remember the radio will only draw as much current as it needs but the power supply has to have the capacity to deliver that amount. The power supply also has to be "regulated" meaning it keeps the voltage at a fixed value (13.8 volts) no matter how much current the radio draws. Just a reminder don't key the transmitter without connecting the proper antenna or a dummy load. Doing so can damage the transmitter.
power for Kenwood TW-4000A KN6CWJ on 22/8/19
Let's back up a bit. The radio requires a power supply of 13.8 volts at a current of up to 7.5 amps. On receive it will be less. The radio will draw only the amount of current it needs. On receive it may only need 1 or 2 amps but on transmit it may draw up to 7.5 amps as noted. What you need is a 12 volt power supply capable of delivering up to7.5 amps (or more) or whatever the radio needs. By the way they are typically called 12 volt even though they are voltage regulated at 12.6 to 13.8. The power supply will have a 120 volt AC cord that plugs into a regular outlet. It will have an output plus (+) and minus (-) connector.
Now 15 volts is probably nearing or over the limit of the radio so reduce the voltage to around 12 to 13.8 volts. The radio may only draw .4 amps on receive.
Hope that helps.
Filtering ac driveinman on 20/12/18
How do you know it is coming in on the AC line and not the antenna?
"wacky"? SWR readings on tuning antennae.. Help?? KM6SQB on 3/12/18
I have found that if you are using a metal mast it needs to be insulated from the dipole mount. I have used a 3 foot piece of fiberglas or plastic pipe. Also make sure the whip isn't inserted so far it engages the top coil of the mast.
adjusting SWR and hamsticks - help?? KM6SQB on 5/11/18
In most cases the resonant frequency will have the lowest SWR. Also you must re-calibrate the SWR meter for each change in power. SWR is the ratio of forward voltage (or power) to reflected voltage (or power). If you are measuring at the transmitter end of the coax use a piece of coax that is 1/2 wave length long at the frequency you are measuring. Don't forget to account for the coax loss in your calculations.

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