FM Radio Station Power Part 12

FM RADIO STATION POWER PART 12

Online mW to W Converter
http://www.rapidtables.com/convert/power/mW_to_Watt.htm

The FM radio station at 100 mW is only .1 watt which is a mere whisper of more powerful radio stations. (1 Watt = 1000 mW)

Relative Power
Measuring the voltage at the antenna can determine the relative power measurement which is useful for tuning, i.e. to a minimal or maximum value. 

Measuring Power
http://www.zen22142.zen.co.uk/Circuits/Testgear/rfprobe.htm

http://preciserf.com/wp-content/uploads/2012/04/Appnote-4-Power-tests1.pdf 

From Code of Federal Regulations Telecommunications 47
Part 80 to End, FCC 80.259
"(c) A reserve transmitter must be equipped to measure antenna current. (d) The antenna power must be determined at the operating carrier frequency by the product of the antenna resistance and the square of the average antenna current both measured at the same point in the antenna circuit at approximately ground potential."

How to Measure Amps or Watts With a Multimeter
Measuring Amps
Step 1: Select the "Current" setting on the main dial of the multimeter. Choose a current range high enough for the circuit being tested. For example, if the circuit has a current that you estimate to be around five amps, select the "10 amp" setting instead of the "1 amp" option. Choosing a setting that is too low can overload the multimeter.

Step 2: Insert the leads into the multimeter connections labeled "current." Typically, the black lead should be connected to the "common" port, while the red lead is connected to a port that matches the selected current range. This arrangement varies, depending on the unit. Consult the multimeter labels carefully to confirm that the configuration is correct for measuring current.

Step 3: Place the multimeter leads into the circuit using a series configuration. The electricity must be redirected to flow completely through the multimeter to obtain an accurate reading. Current should usually move into the red lead and exit the black lead.

Step 4: Read the amount of amperage displayed on the multimeter. Remember to consider this number in the context of the selected current range. For example, the number "10.00" may indicate 10 amps on one setting but only 0.01 amps if the multimeter is set to the smaller "milliamps" range.

Measuring Watts
Step 1: Choose the "Voltage" setting on the multimeter dial. As you did when measuring the current, ensure that the appropriate voltage range is selected. It is usually a good idea to select the highest possible voltage range to prevent an overload.

Step 2: Configure the multimeter leads into the ports marked for "voltage." The black lead can usually remain in the "common" position. Move the red lead to the port labeled for the voltage range being tested.

Step 3: Connect the leads to the circuit in a parallel arrangement. The black lead should link to a negative or grounded point, while the red lead should be touched to a point of the circuit you wish to measure. Unlike a current measurement, a voltage test does not need to be completely redirected through the multimeter.

Step 4: Read the number on the multimeter display. As with current, remember to consider the context of the multimeter range setting.

Step 5: Multiply the amount of current and the amount of voltage in a circuit to determine the watts. For example, a motor circuit that uses 5 amps and 12 volts has 60 watts of power.

A SIMPLE POWER DETERMINATION
Use several incrementing known wattage light bulbs as a test to verify basic power operation of the transmitter. The lamp will present a load to the transmitter that's similar to an antenna. This test may provide a visual indication of the power output from the transmitter, and verify operation of the antenna coupler. Use grain of wheat bulbs for milliwatt ratings.

POWER FORMULA
P=EI, P=(I^2)R where E is voltage in volts and I is current in amps

ANTENNA
The antenna is a small circular loop with a 1.75-inch diameter. It's measurement of resistance for the tiny loop antenna is 0 ohms on every scale from 2K to 20M. The multi-strand antenna wire is a total of 6-inches long. This indicates that power output readings and measurements can be made at the antenna coupler with no antenna needed. The coupler is where the antenna attaches to the board.

The next step is to unravel a length of wire equal to a fundamental size of the wavelength and measure its resistance. If the value is still 0, increase the fundamental, from 1/32th wavelength to 1/16th, then repeat again if the wire still has zero resistance. At 1/8th, the antenna may be too long.

FM Radio Station Part 5 Index
http://humanoidolabs.blogspot.tw/2013/12/fm-radio-station-part-5-index.html

Brain Cortex Power Wiring Part 45

BRAIN CORTEX POWER WIRING PART 45
ELECTRIC JUICE  It's time to attack the brain cortex wiring and complete this phase of the project. Let's get some electric juice going! The jar is home to the brain cortex. Every home needs electrical wiring and the brain's jar is no different. The electric juice will power the brain, lighting, speaker, and sensors.

Wire each twin power unit like this

The next step is wiring the power unit. In this procedure, the battery holders are removed and the ends (+ and -) black and red wires are connected together with yellow twists. Be consistent by connecting the wires on the right sides of the twin holders.

Snap in a size D battery into each battery holder.

Insert batteries outside of the jar

Initially we're using Zinc Carbon batteries (Philips LongLife R20).

Now cut four black wires and four green wires, each 5-inches long, and strip the ends. Connect these with yellow twists to the left side wires on the battery holders. Attach a small piece of Scotch tape to insulate

Taped ends prevents shorts

one end of each wire to prevent a short during the installation.

Measure the voltage of each twin power unit. Remember, a twin power unit equals two batteries and two battery holders connected together in series to obtain 3 volts. (The voltage of new batteries not under load

Finished wiring - test shows 3.13 volts

will be slightly higher than 3 volts.)

Reinstall all battery holders, remembering their correct positions to fit into the jar holes.

Gather up all the green wires, insert one 5" length of green solid wire, and twist the ends together with the  yellow twist. Repeat for the red wires. The two lengths of solid wire will connect to the solderless breadboard. Use a plastic clothes pin to hold all the ends together. Test again for voltage. In the test, the meter shows 3.13 volts for new Zinc-Carbon D cell batteries connected together. Note: during this procedure, the Solar Panel red and black wires are left floating. These may connect later to the solderless breadboard.

The Chinese yellow wire twists are sold in Taiwan, in a package of 20 for NT$20 obtained from the dollar store. The brand is manufactured under authority of Sellery Inc. California USA, and the DIY item number is TE-18. http://www.sellerytools.com  886-2-26103915

Note: The battery holders each have a red and black connection wire. Supply a 5-inch length of wire and connect it to the lowest wire nearest to the jar floor. This enables it to reach the top where similar colored wires connect together. 

Index to the Brain Cortex
http://humanoidolabs.blogspot.tw/2013/11/brain-cortex-index-part-16.html