Sit. Rep. #136: Listen and Hear, 4 cycle

Ears for listening:

1- Listen.  Name all the sounds that you hear.  Listen in the dead of night.  Listen on a camping trip when no one is talking or moving.  Listen to the weather.  Listen to the wildlife.  Listen for what is missing.  Listen with your eyes to see what or who is making the noise.  Listen without moving your head.  Let nature come to you.  What can you observe?  What can you deduce from your observations?  Can you tell the difference between the facts of observation and deduction from clues?

A: I heard that you almost drowned by falling into the river up to your knees.
B: Yep, I sure did. I fell in headfirst.

4-Cycle engines:

2- 4 cycle engines are sometimes called 4 stroke engines.  There are 4 phases of the power-producing process.  Those 4 processes are aligned with valves, piston movement (inside of the cylinder), and ignition.
1 Intake
2 Compression
3 Power
4 Exhaust

1 Intake:  The piston is moving down the cylinder.  The intake valve is opened to allow air and gas (fuel) to flow into the cylinder.  Sometimes there is a direct fuel injector that blows fuel into the cylinder without going through the intake manifold.  The intake valve closes at the bottom of the piston stroke.

2- Compression:  The fuel-air mix is compressed as the piston moves up the cylinder.  The compression heats up the fuel-air mix and increases the efficiency of the engine by getting more energy out of the next phase.

3- Power: Very close to the top of the piston movement ignition occurs.  In a diesel, it happens because the compression heat climbs above the ignition temperature of the fuel-air mix.  In a gasoline engine, a spark plug creates a spark that ignites the fuel-air mix.  Either way, the fuel-air mix explodes and forces the piston down.  The piston is linked to the drive shaft through a connecting rod.  This phase creates the energy (horsepower and torque) to rotate the drive shaft.

4- Exhaust: After the piston bottoms out the exhaust valve opens and the burned gasses are forced out as the piston moves up the cylinder.  At the end of the exhaust phase and the exhaust valve closes.  And then starts all over again with #1-Intake.

Repeated over & over again.

Capture this:  If a one-cylinder engine is turning 1600 rpm (revolutions per minute).  How many times is the spark plug firing?  800 times per minute.  The spark plug fires every other revolution.

C: Why did you call the bread baker lazy?
D: All he did was loaf.

Radio equipment:

3- Ham Radio Equipment:

What is a transceiver?
     A unit combining the functions of a transmitter and a receiver

What device converts the RF input and output of a transceiver to another band?

What device increases the low-power output from a handheld transceiver?
      An RF power amplifier
What is the function of the SSB/CW-FM switch on a VHF power amplifier?
     Set the amplifier for proper operation in the selected mode

Which term describes the ability of a receiver to detect the presence of a signal?
Which term describes the ability of a receiver to discriminate between multiple signals?

Where is an RF preamplifier installed?
      Between the antenna and receiver

Which of the following is used to convert a radio signal from one frequency to another?

What is the name of a circuit that generates a signal at a specific frequency?
Which of the following describes combining speech with an RF carrier signal?

Dan Romanchik KB6NU, (Ham Radio)  Technician Study Guide

E: Why did the auto mechanic to art school?
F: She wanted to learn how to make a van-go.

Meeting Plans & Notes:

Learn how to safely jump-start a car.
Learn how to hook up a battery charger.
Learn how to change a tire.

Semper Paratus,

Scout Skits: by Thomas Mercaldo

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