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Antenna Modeling for Beginners Feb 8th 2013, 18:19 3 3,041 on 14/2/13
Roller Inductor Tuner Dec 20th 2011, 19:26 1 2,996 on 20/12/11
Using Ladder Line Jul 27th 2011, 19:43 3 4,468 on 29/7/11

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Topic Author Posted On
power for Kenwood TW-4000A KN6CWJ 1 day, 1 hour ago
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.
Grounding station vs Vertical Antenna and tower VE3SR on 29/10/18
Normally ground rods are spaced twice their length apart. 8-foot ground rods would be placed 16 feet apart for maximum effectiveness. The NEC also requires all external ground rods be connected to the building main electrical ground.

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