# 29 Engineering

## 29.1 Electrical Circuits

### 29.1.1 Phase Locked Loop

A phase locked loop consists of a phase detector, a low-pass filter, and a voltage-controlled oscillator (VCO). The locked output comes out of the VCO and is fed back into the phase detector, which compares the phase with the input signal. The larger the phase difference, the smaller the DC voltage output of the phase detector, but there are also the extraneous original frequencies, harmonics, and sum frequencies. The subsequent low-pass filter strips these off forwarding the more slowly changing DC voltage. If the phase increases the lower voltage will increase the VCO frequency until it catches up with the input signal. If the phase decreases the higher voltage will reduce the VCO frequency until it slows to the input signal.

Figure 29-1: Phase Locked Loop

### 29.1.2 Resonance

The advantage of resonance in a circuit is that it permits the circuit to act as straight though wire at resonance. For example this permits the selection of the ideal AC coupling capacitor.

Figure 29-2: Solving for a Resonance Capacitor or Inductor

## 29.2 Electromagnetic Fields

### 29.2.1 Vector Calculus

Perpendicular vectors have dot products that are zero due to the cosine(90) being zero.
Parallel vectors have cross products that are zero due to the sin(0) being zero. This means the magnitude of the normal is zero for parallel vectors.

### 29.2.2 Maxwell’s Equations

Maxwell’s equations derive from Ampere’s law and Gauss’s law for statics.

The integral forms derive from the Differential forms using Stokes’ Law[2904] and the Divergence Law.

Equation 29-1: Stokes' Theorem
The line integral of the vector A along a closed path C is equal to the integral of the dot product of the curl of the vector A with the normal to the surface S that has the contour C as its boundary.

Equation 29-2: Divergence Theorem
The closed surface integral of the normal component of vector A over a surface S is equal to the volume integral of the divergence of A over the volume V enclosed by S.

Equation 29-3: Ampere's Law
Ampere’s law for statics is x H = J. Maxwell added the electric displacement current density J= ∂D / ∂t.

The third law of Maxwell’s equations is Gauss’s law.[2905]

Equation 29-4: Gauss’s Law
Electric flux flowing out of a closed surface = charge enclosed

s D • dS = v q dV

where the vector dS = n*dS is a vector in the outward normal of the surface with magnitude dS.[2906]
where the vector D is the Displacement Vector = Electric Flux Density = D = ε * E

D cos θ dS = s D • n dS = s D • dS

### 29.2.3 Electrical Properties of Matter

Materials are:
• Dielectrics (insulators) – Polarization (electric displacement current density) is predominant phenomenon. The formation of electric dipoles between opposite charges of atoms or in atoms is the source of polarization.
• Magnetics – Magnetization (magnetic displacement current density) is predominant phenomenon.
• Conductors – Conduction (conduction current density) is the predominant phenomenon. The prominent characteristic is the motion of electric charges and the creation of current flow.[2907]

Polarization is in C/m2 – Coulombs per square meter, which is a bound surface charge density qsp.
An increase in temperature for a conductor increases the thermal energy in its lattice structure causing lattice vibration and more collisions for moving electrons, thus a decrease in conductivity.

Semiconductors bridge the gap between Dielectrics and Conductors. In intrinsic (pure) semiconductors the carriers include:
• Free electrons
• Bound electrons – positive holes
Mobility is (drift velocity)/(unit E field). In semiconductors, drift velocity decreases with increased temperature due to collisions. However, charge density increases with temperature. Hence, with increase in temperature, mobility decreases, while conductivity increases.

Table 29-1: Temperature Increase effects on Materials
 Drift Velocity [m/s]ve – drift velocity of electronsve = - μe E where E is V/m Mobility [m2/(V-s)]μe – mobility of electronsμh – mobility of holes Conductivity Metallic Conductor Electrons drift in the negative direction of an applied electric field In conductors, positive and negative charges are separated by macroscopic distances. This is a fundamental difference between true charges in conductors and bound charges in dielectrics.[2908] Decreases Semiconductor Decreases Decreases Increases Superconductor T↑ ve↑T↓ ve↓ since E→0T→TC (~0K) E→0 Constant For T→TC(~0°K) σ→∞ TC – Critical Temperature

The three constitutive properties characterize the electrical property of the material.

The permittivity – ε indicates the storage capacity of a material and is in (Farads/Meter). It indicates how well a material permits an Electric field to pass through. The scale is in an inverse sense such that a vacuum has the smallest permittivity (8.854 * 10-12) and lets the largest E-field pass, so higher permittivity is higher resistance or more specifically reactance per meter. While a higher permittivity, dielectric such as water at 81 would serve as an excellent capacitive material in storing an E-field for release.

The permeability – μ indicates the inductive quality of the material and is in (Henries/Meter). The larger the permeability the material may store a larger magnetic field. In Free Space the permeability is 4π * 10-7 Henries/Meter.

The conductivity – σ is the inverse ohms per meter and indicates the charge movement quantity capability of the medium 1/(Ω Meters).

Table 29-2: Constitutive Parameters of a Material for Electrical Characterization
 Permittivity – ε Permeability – μ Conductivity – σ Units Farads/Meter Henries/Meter Siemens/Meter or MHO/Meter or 1/(Ω Meters) Description Capacitive storage of the material as a function of frequency. Inductive storage of the material as a function of frequency. Charge movement capability of the medium as a function of frequency. Free Space Value 8.854 * 10-12 F/m 4π * 10-7 H/m 0 MHO/m Relation (* denotes convolution) D = ε * E B = μ * H Jc = σ * E

The permeability of most dielectric material is the same as free space.

Frequency, permittivity and conductivity that is the loss tangent specify whether a material is a good conductor or a good dielectric:

σ/(ωε) >> 1 Conductor – conduction current density prevails Jc
σ/(ωε) << 1 Dielectric – displacement current density prevails Jd

where σ/(ωε) = tan δ

Hence, the loss tangent tells us the operational behavior of a material at a particular frequency.

Table 29-3: Current Density
 A/m2 Name and Description Equivalence J Total Current Density Jc Conduction Electric Current Density – Physically, conductors are material whose outer shell valence electrons are not held tightly and migrate from atom to atom.[2909] These valence electrons are called free electrons, since they move easily. Jd Displacement Electric Current Density – In dielectrics, the motion of bound charges, create a true current and constitute part of the displacement current density.[2910] Physically the electric flux in a region displaces a bound electron in a filled shell from an atom or molecule, which moves to its neighbor displacing another bound electron. The process creates a true current. Jd = ∂D/∂t = jωD = jωεEthat is the change in the Electric Flux Density[2911] in C/(s-m2) Ji Impressed (source) Electric Current Density – A current source that can create a conduction electric current density if there is a conductor or a displacement electric current density if there is a dielectric in its path. Jm Bound magnetic current density – This current density is the direct result of polarization derived from Jms below. The dipoles are bound in the material except for their orientation. The current density is in a loop with the polarization in the normal direction. Jm = ∇ x M (A/m2) Jms Bound Magnetic surface current density is a net result of all dipole moments since the internal microscopic current densities cancel.[2912] Jms introduces the magnetization vector or magnetic polarization vector M (A/m) that is in the same direction as the applied magnetic field Ba.[2913] M tells the magnetization dipole density in the material. Jms = M x ń|surface gives the direction around the surface Jp [2914][2915] Jp = ∂P/∂t

The secondary properties describe the dependencies of the constitutive parameters.[2916] Graphically, convolution of two waves is taking the mirror reflection of the second wave and moving it towards the origin of the first wave, while plotting the area under the curve as a function of time given by the slide of the intersection.

Table 29-4: Secondary Parameters of a Material
 Property Definition Linear Constitutive properties not a function of the applied field strength.[2917] Nonlinear Constitute properties are a function of the applied field strength. Homogeneous Constitutive properties not a function of position in the media. NonhomogeneousInhomogeneous Constitutive properties are a function of position in the media. Isotropic Constitutive properties not a function of the direction of the applied field. NonisotripicAnisotropic Constitutive properties are a function of the direction of the applied field. A permittivity tensor[2918] gives the relationship between the electric flux density and electric field in three dimensions with D = ē • E Dispersive Constitutive properties are a function of frequency. Nondispersive Constitutive properties not a function of frequency.

The electrons surrounding the nucleus of an atom also spin around their own axis. Each contributes a ±9 E-24 magnetic moment.[2919] Only the electrons found in incompletely filled shells contribute to this magnetic moment as the ones in filled shells cancel each other out. The nucleus of an atom also has a spin, but the nuclear spin is much smaller than the electron moment by a factor of E-3.

Table 29-5: Magnetic Properties of Matter
 Material Class Permeability Cause Description Diamagnetic 0.999 ≤ μr < 1 Atoms or molecules with no intrinsic magnetic dipole moment are distorted by the applied magnetic field to acquire an induced dipole moment antiparallel with the applied field.[2920]In the absence of the applied field, thermal agitation randomizes the orientation and there is no net alignment along a preferred direction.[2921] The net small magnetization vector opposes the applied magnetic field resulting in permeability just below unity. In a magnetic field, their induced magnetism is in a direction opposite to that of iron.All materials, with or without intrinsic moments are subject to the diamagnetic distortion, but it is a weak effect easily masked by the paramagnetic alignment when present. Vacuum μr = 1 Paramagnetic (Antiferromagnetic - noting or pertaining to a substance in which, at sufficiently low temperatures, the magnetic moments of adjacent atoms point in opposite directions.) 1 < μr < 1.001 When applying a magnetic field dipoles align slightly producing a small non-zero M in its direction and a small increase in the magnetic flux density within the material. Magnetic moments of spinning electrons of an atom do not cancel each other out in the absence of an applied electric field. However, in the macroscopic view, multiple atoms cancel each other’s magnetic moments.Above the Curie temperature point ferromagnetic materials revert to paramagnetic behavior.[2922]For ferromagnetic materials, a remarkable quantum mechanical phenomenon causes the intrinsic moments to self-align over regions of the material called domains. Net magnetization vector aids magnetic field resulting in a relative permeability greater than 1. Also, there is a magnetic susceptibility χm slightly greater than 0. A body or substance that, placed in a magnetic field, possesses magnetization in direct proportion to the field strength; a substance in which the magnetic moments of the atoms are not aligned. Ferrimagnetic and the subclass Ferrite(Often from metal oxides or ceramics – high permeability, i.e. strong magnetic effect – strong interaction with a magnetic dipole. High dielectric constant.) 10 ≤ μ ≤ 250Ferrites are a class of ceramic materials that are good insulators, high mu, 10< eps <15, specific resistivities E14 greater than metals.Magnetically lossy accounted for with a complex permeability. Ferrites in addition have low conductivities, i.e. large resistance. Thus, they have low losses in the face of alternating current and produce isolators, hybrids, gyrators and phase shifters.“Ferrites have their magnetic ions distributed over at last two interpenetrating sublattices. A sublattice has magnetic moments aligned but sublattices are oppositely directed.”[2923] Noting or pertaining to a substance, as a ferrite, in which the magnetic moments of some neighboring atoms point in opposite directions, with a net magnetization still resulting because of differences in magnitudes of the opposite moments. Ferrite have non-reciprocal properties including different phase constants and phase velocities for right vs. left-hand circularly polarized waves, different transmission coefficients as a function of direction of travel, permeabilities that are tensors. Ferromagnetic 250 ≤ μ ≤ 1,000,000High conductivity and thus cannot hold a field. Thus, they serve to zero out electromagnetic fields. Magnetically lossy accounted for with a complex permeability. The individual atoms in the absence of an applied magnetic field still possess very strong magnetic moments from uncompensated electron spin moments. After applying a Magnetic field, domains, groups of atoms with the magnetic moment in the same direction, line up and this creates a residual magnetic field or Magnet even when removing the external magnetic field.[2924] Noting or pertaining to a substance, as iron, that below a certain temperature, the Curie point, can possess magnetization in the absence of an external magnetic field; noting or pertaining to a substance in which the magnetic moments of the atoms are aligned.

### 29.2.4 Wave Equations

The propagation constant equals the attenuation constant plus the phase constant:

γ = α + jβ

Phase velocity is:
vp = ω/β

Beta is the phase constant, phase number, or wave number and is in radians/meter. Also

β = 2π/λ

Beta is the number of waves there are in a meter multiplied by 2π. Hence, Beta is directly proportional to frequency since:
λ = c/f
β = f * 2π/c
β = ω/2π * 2π/c
β = ω / c

where ‘c’ is the speed of light. If we are not in free space than we replace ‘c’ with ‘vp’ and end up with a form of the equation of phase velocity above.

## 29.3 Computer Networking

### 29.3.1 Standards

We can breakdown communication into five layers of operation from higher logical layers to lower physical implementations. These are the OSI standard Layers.

Table 29-6: Internet Protocol Stack
 Layer IP Stack Protocol Stack or Data Unit (PDU) 5 Application – HTTP – web support SMTP - email support FTP – file transfer Message – This is can be an IPC – inter process communication message. 4 Transport TCP UDP Segment 3 Network IP – Internet Protocol DatagramSource RoutingVirtual circuits 2 Link – routing layer Ethernet ATM Frame Relay PPP – modem communication FrameCollisions and backoff 1 Physical Twisted pair copper Co-axial cable Fiber optic PDU1 – Each Layer 2 Link may have a different protocol for transmitting bits over the different mediums.

#### 29.3.2.1 Ethernet

Ethernet operates at Layer 2 and its main feature is that it shares the physical network by supporting collision sense and multiple access and collision avoidance (CSMA/CA).

#### 29.3.2.2 ATM

ATM provides protocols from the transport layer down through the physical layer. ATM sends data in cells of 53 bytes in length. Each cell has a 5 byte header and a 48 byte payload. Fixed length cells and simple headers facilitate high speed switching.[2925] ATM supports virtual channels through its cell header virtual channel identifier (VCI). Packet switches or routers read the VCI and route cells towards the destination. ATM runs over any physical layer achieving speeds of 600 Mps over fiber optics. TCP/IP is operating over 100 Mbps Ethernet and holds a standard position in the PC and LAN arena. IP over ATM operates by a router first processing the IP header and then using the ATM ARP table to process and send the ATM data.

Asynchronous Transfer Mode provides network-assisted congestion control. In essence as a cell of data travels from source to destination, switches along the pathway add information to Resource Management cells denoting on the congestion level. Either the switch or the destination will return the RM cell back to its source. The source in turn will process the RM cell to adjust the maximum rate at which to send data. The source intersperses RM cells amongst Data cells.

Each data cell contains an EFCI (explicit forward, congestion indication) bit. If a switch sets the EFCI bit in a data cell then the destination knows that it must return congestion information to the sender. Consequently, the destination will set the CI (congestion indication) in the subsequent RM cell before returning the cell to the sender.

An RM cell also contains the NI (no increase) bit that a switch may set in a passing RM cell to indicate mild congestion. The switch may set the CI bit on more severe congestion. The destination may return the RM cell intact, or adjust the CI bit itself based on an EFCI from a preceding data cell. Each RM cell also contains a two-byte ER (explicit rate) field. As the RM cells passes from source to destination, the congested switch may only lower ER to the rate of itself. In this manner, the ER field will contain the minimal rate of the entire path when the RM cell is returned to the source.[2926]

### 29.3.3 Network

The IP Layer 3 defines Internet communication.

### 29.3.4 Transport

#### 29.3.4.1 TCP/IP

TCP/IP provides end-end congestion control. TCP – Telnet Communication Protocol provides interactive communication. IP – Internet Protocol provides reliable data transfer.

## 29.4 Satellite Theory

### 29.4.1 SATCOM

SATCOM – satellite communications applies astronomy, communication theory, and electrical engineering in the development of satellite technology. Uplink frequencies use the higher frequency of the bands while download is of lower frequency. Higher frequency transmission requires more power as the quanta of energy is proportional to frequency. One advantage is that a smaller satellite dish is sufficient to capture a signal at a higher frequency. Newer satellite TV systems transmit at higher frequencies and customers consequently get by with smaller dishes on their roofs.

Table 29-7: SATCOM Frequencies
 Frequency Range in GHz Frequency Band Usage 0.1-0.3 (100-300 MHz) VHF Basic TV transmission 0.3-1.0 (300-1000 MHz) UHF Extended TV transmission 1.0-2.0 L 2.0-4.0 S 4.0-8.0 C FSS – fixed satellite services. These included original cable transmission to centers for distributing cable TV. Later these signals were encrypted to prevent pirating FSS channels with large satellite dishes. 8.0-12.0 X 12.0-18.0 Downlink 12.2 – 12.7 Uplink 17.3 – 17.8 Downlink 11.7 – 12.2 Uplink 14 – 14.5 Ku – High Power BSS – broadcast satellite service DBS – direct broadcast satellite Point to point allowed too. No adjacent satellite interferenceKu – Medium Power FSS – fixed satellite service Point to point primary use DBS allowed too. Adjacent satellite interference Covers broadcast satellite TVNo terrestrial interference. 9 degree spacing – ITU reg.EIRP (equivalent isotropic radiated power) – 51-60 dBW2 degree spacing – FCC regulated.EIRP – 40-48 dBW 18.0-27.0 K 27.0-40.0 Ka 40.0-75 V 75-110 W 110-300 mm This would be millimeter-wave which occurs in guided missile communication. 300-3000 μm

INTELSAT – International Telecommunications Satellite regulates international satellite location and operation assignments. Individual countries on the other hand operate Domsats – Domestic satellites for services such as voice, data, or video conferencing within a country. Domsats are in geostationary orbit so they have a constant position over a particular country. There is only one geostationary orbit for the world and that is over the equator. Satellites operate at 36,000 km in this functional area.

In contrast to the singular geostationary orbit, there are an infinite number of polar orbits. Weather satellites operate in polar orbits, usually at altitudes of 800 and 900 km. NOAA operates both geostationary operational environment satellites, GOES, and polar operational environment satellites, POES. The polar orbiting satellites are sun synchronous, i.e. crossing the equator at the same local time each day. There are two polar satellites in orbit at a time.

Table 29-8: Polar Orbiting Satellites
 POES Satellite Height Direction TOD crossing equator Morning orbit 830 km south to north 7:30 AM Afternoon orbit 870 km south to north 1:40 PM

NOAA satellites participate in search and rescue, SAR operation. Russian satellites support this network with Cospas. NOAA satellites operate with Sarsat.[2927] Originally, SAR operated only with satellites in low earth orbits, LEOs, supporting the system LEOSAR. Recently, NOAA added geostationary satellites to their services, which constitute GEOSAR.

When a vehicle becomes lost, its emergency beacon transmits a signal in the VHF/UHF range at a precise frequency. The velocity of the satellite relative to the beacon enables the satellite to measure the Doppler shift. As a POES satellite nears the latitude of a lost craft’s beacon, the received frequency is higher than the transmitted frequency. As it recedes from the beacon, the received frequency is smaller than the transmitted frequency. In this manner the POES determines the latitude position. On the second pass, the change in the earth’s rotation permits the satellite to determine the effect of rotation on the Doppler shift and to identify a precise longitude position.

Sarsat’s downlink frequency is 1544.5 MHz. to local user terminals, LUTs. The higher frequency alleviated the false alerts caused by interference from the older emergency locator transmitters, ELTs, operating at 121.5 MHz. There are about 600,000 distress beacons on aircraft and small vessels.

Table 29-9: Emergency Locator Transmitters
 System ELT Frequency False Alerts Operation Power Positional Accuracy Compas-Sarsat 121.5 MHz 98% LEOSAR, polar orbit, Doppler shift, no identification info. a few tenths of a watt 10-20 km New Compas-Sarsat 406.028 MHz Changed from 406 MHz to avoid conflict with GEOSTAR LEOSAR, 5 watts 3-5 km GEOSAR 406 MHz Stationary orbit, GPS operation, no Doppler shift from stationary orbits.

## 29.5 Frequency Allocations for Broadcasting

Radio signals are vertically polarized while TV signals are horizontally polarized.
Table 29-10: Frequency Allocations for Broadcasting
 Band Frequency Range Good Antenna Length Description AM 535-1605 KHz 140 m. – 47 m. ~107 channels: Interchannel Spacing 10 KHz FM 88-108 MHz 0.85 m. – 0.69 m. 100 channels each 200 KHz wide SW (international) 5.95 – 26.1 MHz 12.6 m. – 2.9 m.

## 29.6 Microwave Engineering

### 29.6.1 Skin Depth

Skin depth of microwave frequency radiation is dependent on the conductivity of skin which varies with frequency.

Equation 29-5: Skin depth of Radiation

δs = sqrt (1/(f *π*μ0*σ)) where σ is the conductivity of the material. μ0 is mobility in free space 4πe-7.
For sea water σ = 4 siemens/meter at 10 GHz gives δs = 0.002515 meters or ~ 2 mm.
The conductivity of skin varies over frequency so σ ≈ 1:10 siemens/meter from 1:10 GHz.[2928]
A microwave oven works at 2.45 GHz.

Figure 29-3: Radiation penetration of skin vs. Frequency

### 29.6.2 Fault Detection in a Cable

The Reflection coefficient is negative for a short circuit type of fault or positive if the fault is of an open circuit type from the following analysis. ZL is the load resistance that is 0 for a short circuit or infinity for an open circuit. Z0 is the intrinsic impedance.

## 29.7 Test Engineering

Isolating problems in test engineering is similar to being a detective. These axioms apply:

Text 29-1: Arthur Conan Doyle—Sherlock Holmes on Deduction
If you eliminate the impossible, whatever remains, however improbable, must be the truth.
There should be no combination of events for which the wit of man cannot conceive an explanation.
When all other contingencies fail, whatever remains, however improbable, must be the truth.
Very effective my dear Watson. —Elementary my dear Holmes, Elementary.[2929]

In soldering the solder will move to the location of the heat. To reflow pins apply the iron on top of the pin to draw the solder upwards. Might have to supply a little bit of solder below the pin. Flux helps the solder attach to the metal. Clean the remainder of the flux off with alcohol afterwards. To find pins that are loose, use a steroscope with a fine probe to see if the pins move.

## 29.8 Processes

### 29.8.1 Six Sigma

 Sort "When in doubt, throw it out." Straighten "A place for everything, and everything in its place." Shine "Clean everything, so you can see the problems." Standardize "Develop methods to maintain the 6S system." Sustain "Maintain a self-disciplined approach to the 6S system." Safety "Make it safe, make it count."

Table 29-11: Six Sigma Benefits
 Process Benefit Sort Creates more space, removes defective items from inventory. Helps you get rid of what you do not need. Items used less often should be away from work area and stored. Straighten Ensures what remains is tidy and available where and when you need it. Consider frequency of usage in arrangement. Shadow boards can display tools in less space. Shadow boxes too. FIFO for expiring items. Shine Ensures a spotless environment with constant improvements to the way the area is cleaned, inspected, and maintained. Zone assignments for cleaning schedule. Standardize Ensures the continued success of 6S with environmental controls: Shadow boxes, shadow boards, color-coding. Poka Yoke – mistake proof,[2930] Kanban,[2931] Visual Controls. Label size on boxes of screws. Color code place holders of colored tools. Sustain Requires education and self-discipline to form good habits: checklists, assigned responsibility. Safety Avoid situations that can cause repetitive injury.

Sort

"When in doubt, throw it out."

Tools:

Tag
Shared workspace
Garbage can

Rules:

Items used daily should be within arm's reach.
Items used weekly should be within a step or two.
Items used less often than once a week should be located away from your work area (shared, stored, or thrown away).

Straighten

"A place for everything, and everything in its place."

Tools:

Frequency chart
FIFO (First In ... First Out)

Rules:

Learn what's going on.
Develop a structured approach to putting things away

Shine

"Clean everything, so you can see the problems."

Tools:

Zone assignments for daily cleaning

Rules:

Inspect as you clean.
Ask: Why did this item get dirty?
Ask: Could it be standardized to avoid the dirtiness?
Ask: Could the machine clean itself?

Standardize

"Develop methods to maintain the 6S's."

Tools:

Tools from previous sections:
Tag
Frequency chart
FIFO (First In ... First Out)
Poka yoke (mistake proofing)
Visual controls
Kanban

Rules:

Ensure all methods are clear and understood.
Anybody should be able to understand how to operate within any environment.
Best practices are shared across the facility.

Sustain

"Maintain a self-disciplined approach to the 6S's."

Tools:

Education
Everyone's involvement
Checklists
Clearly assigned responsibility

Rules:

Form good habits.
Positive change starts with you.

Safety

"Make it safe, make it count."

Tools:

Personal Protective Equipment
Awareness

Rules:

Avoid repetitive motion
Pay attention to and correct possible hazards with your environment

### 29.8.2 Lowering the Thermostat to Save Energy

At night, one can lower the thermostat to a minimum of 55 degrees. For each degree reduction for an eight-hour period, one can save 1% on heating costs.[2932] For example, for a 5-degree reduction for 16 hours, one can save 10% on the monthly heating bill and even more if the heating rates are progressive. Pipe freezing may occur if the house is set to 50 degrees so there is a 5-degree margin here. “If you're away from home during winter, set the thermostat in your house to no lower than 55 degrees to prevent pipes from freezing during a cold snap while you're away. Open cabinet doors to allow heat to get to un-insulated pipes under sinks and appliances near exterior walls.”[2933] Open access doors to the main water valve to allow heat in this region. Freeze proof faucets to the outside of the house can freeze up if they are leaking and blocked by a hose left on during winter. Hence, I recommend 65 degrees as a minimum.

“For winter operation, consider setting the thermostat to 55 degrees at night when you sleep and at 68 degrees when you're home. (In colder parts of California, it's not recommended to set the temperature below 50 degrees, because indoor water pipes may freeze.)

For summer operation, set the temperature to 78 degrees when you're home and at 85 degrees or higher when the house is unoccupied. In the summer season, you might need to program your thermostat to cool only for one period of the day, such as the late afternoon and evening hours, when the family returns home.”[2934]

## 29.9 Security

Avoid having a car remote on display as they break into the car, steal the registration and they know your not home and then burglarize the house. A home alarm system and security decals are a deterrent. A dog is a deterrent. A police officer told me once that he had never arrived at a house on time due to a monitoring system to catch the burglar still there.

Burglary Prevention Tips

Your home is your sanctuary. Your home is your safe zone, it’s a place where you and your family have complete control and feel comfortable. It’s and environment that you feel protected from burglars / intruders. In order to have a safe home you have to understand all areas a burglar looks at in order to find your weakest spot.

Home Burglary Overview

Home burglary is the number one biggest threat to your home. According to statistics a home is broken into every fifteen seconds. If your home is broken into it will leave you family feeling violated and vulnerable. Its your responsibility to take the minimal measures to prevent this sort of action on your home. To gain a basic understanding you must first get into the mind of a burglar.

Here are some high level stats. From timing perspective homes are more likely to be broken into during the day while you and your family are at work and school. From a seasonal perspective your home is more likely to be burglarized during the summer months than winter. There is a spike in the months of July & August and a low in February. Burglars are typically under the age of 25 and are committed to finding items that can easily be converted to cash. Some of those items are cash, big screen tvs, blue ray players, dvd players, cd players, ipods, cds, jewelry, computers, general electronics. More often then not a burglar will enter the house using force if necessary. They prefer to go through an open door but are always prepared to use force. Burglary will continue to flourish because police can only manage to catch 13%. That stat tells you the you need to take accountability in preventing this. Adding a home security system is the number one way of deterring burglars.

Doors and Locks
Obviously doors are the easiest way to enter your home. Securing this is the number one way of preventing intruders. You need to make you home look like it is a lot of effort. If your home looks like too much work and time then that increase the probability of the police catching them. Most homes have a front, back and garage door to enter their home. Most experience burglars know that the garage door entry is typically the weakest link. Locks are measured by grades. The lower the grade number the high the protection as well as cost. For all exterior doors you should be using grade 1 or grade 2. This will protect your door from being pried and picked. Using quality door knobs will also prevent from slipping the lock using credit cards.

The most common way of preventing a forceful entry is ensuring you have a solid door and frame.

Sliding Glass Patio Doors
Sliding glass doors are notorious for weak points in a home. Burglars will attempt to derail the door or forcefully break the latch mechanism. First ensure that the lock mechanism is metal not plastic. You need more then a metal lock mechanism from preventing intruders from breaking and entering. Add a second lock by placing board preventing the door from sliding.

Older sliding glass doors can be lifted off the runners defecting the lock and sliding prevention device. This can be prohibited by keeping the rollers in good condition. You can also install anti-lift prevention pins. Also, if you have an alarm system keeps it visible so deter the burglar.

Windows
Windows are the second most common way for a burglar to enter you home. Keep windows closed and locked when not home. For extra security measures add a secondary lock mechanism for sliding windows. Typically a wooden stick or dowel will add the extra security needed. Burglars lean towards breaking into ground level windows or windows accessible from tree or ledge. Use anti-lift pin mechanisms to prevent intruders from lifting the window off the runners. As a deterrent, make sure alarm system security decals are visible form outside windows.

Be a Good Neighbor
Get to know your neighbors. By you knowing your neighbors and your neighbors knowing you, you will be able to identify and report suspicious behavior. To be honest with you, this is the number one best security you can get. Good neighbors will lookout for each other. If a neighborhood watch doesn’t already exist you and your neighbors should form one.

Lighting
Leaving a light on when you are on vacation or asleep at night is good; it shows a sign of life. Lighting is important to identify suspicious outside behavior. At night time its good to keep the outside lighting on timers. The nighttime outside lighting should be bright enough to see 100 feet. Security lights with infrared motion detection are my biggest recommendation. These lights are relatively inexpensive and highly effective for outside security. Security lights are highly recommended for family homes.

Alarm System
Home security systems are highly effective. Home security systems increase the probability of a burglar of getting caught. They increase the complexity/time of breaking into your home. If the burglar gets in, time can be limited because you can setup a silent alarm, decreasing the amount of time the burglar has in your home. Homes protected by ADT security systems will typically display the décor on their lawn. This deters burglars. It’s important to display this decal because it will prevent a burglar from even breaking a window and sounding the alarm. It’s important that you instruct your neighbors what to do if they hear the home alarms going off. You should ensure the audio on your alarm system is up to speed. It’s important to have an alarm system installed, it’s equally important to have the proper maintenance done on the alarm system year over year.

Home Safes
Use safety security deposits for must have documents. Use home safes for valuables. You will be surprised how cheap a home safe can be.

## 29.10 Home wiring

Narrow prong of plug is the hot side going to the smooth written wire and the wide prong is the neutral going to the ribbed insulated wire.

Hot wires are black and neutal wires are white. In light switches the hot wire should go to the timer or switch hot side so that when the circuit is open, there is no energized power in the load that can be shorted to ground, e.g. if you place your finger in the light socket you cannot get a shock shorting the conductor to ground. The hot wire or line goes to the circuit breaker box and can be measured with a voltmeter if the breaker is engaged. Otherwise it should be going into the hot side of the light switch. For a toggle, the hot wire or line would connect to the bottom end and the top end would be going to the load. When the switch is off (down) the energy is stopped at the switch and when the switch is flipped up it passes out to the load. For a single pole light switch it doesn’t make much difference but it is good to follow the convention. One can also cover the screw wires that are energized with electrical tape so that they don’t contact the surrounding box, but with time the tape can dry out and result in FOD in the electrical box.

Identifying the wire that is the load can be done with an ohmmeter where a finite resistance will be seen while the line or power source hot wire will have infinite resistance with the breaker open.

To replace a two black wire light switch with a 4 wire timer switch. Connect the hot black wire to the black wire. Connect the load black wire with the red wire. Connect the white neutal wire with the neutal bundle in the switch box. Connect the green ground wire with the green ground bundle in the switch box that should have a bare copper wire running to the switch box wall.

The convention is for hot wires to come in the bottom of switch boxes while loads go out the top.

(http://en.wikipedia.org/wiki/Multiway_switching has a fair discussion of multiple switch wiring)
(http://waterheatertimer.org/Program-wire-Utilitec-0192773.html Utilitec 0192773)

## 29.11 Place Holder

[2904] Advanced Engineering Electromagnetics, Balanis, p.5.
[2905] Advanced Engineering Electromagnetics, Constantine Balanis, p.6
[2906] Fields and Waves in Communication Engineering, Ramo, p.13
[2907] AEE, p.59
[2908] AEE, p.44
[2909] AEE, Balanis, p.60
[2910] AEE, Balanis, p.3
[2911] AEE, p.80
[2912] AEE, pp.53-54
[2913] AEE, Balanis, Fig.2-9.p.54.
[2914] AEE p.45
[2915] Random House Dictionary
[2916] AEE, Balanis, pp.7-8
[2917] AEE, Balanis, p.71
[2918] Ibid, p.71
[2919] AEE, Balanis p.56
[2920] Classical Electromagnetic Radiation 3rd Edition, Heald and Marion, 1995, p.23
[2921] Ibid
[2922] Classical Electromagnetic Radiation 3rd Edition, Heald and Marion, 1995, p.24
[2923] AEE, Balanis p.85
[2924] Advanced Engineering Electromagnetics, Balanis p.58
[2925] Computer Networking, Kurose and Ross, p 57.
[2926] Computer Networking A Top-Down Approach Featuring the Internet, James Kurose and Keith Ross.
[2927] Sarsat refers to locating equipment on the satellite.
[2928] http://ej.iop.org/links/q47/cAkVjWiQU1Qf9fZG,l18cA/m10603.pdf Changes in the dielectric properties of rat tissue as a function of age at microwave frequencies http://www.telecomlab.gr/2002/oct/rhodes/pap3rs/N%20123%20(p875%20-%20p881).pdf Heat Effect Analysis of Microwave Exposed Skin by Using a Multilayer Human Skin Model
[2929] This is from when Sherlock Holmes tries to determine a frequency for repelling flies, while Watson resorts to the fly swatter.
[2930] This is a fence around the danger zone, not unlike the oral law fencing commandments around the written law.
[2931] Visual signal indicating when supply is high or low such as lines on a wall where inventory is stacked.
[2932] http://www.utah.gov/governor/docs/Energy_Conservation_Tips.pdf
[2933] http://www.statefarm.com/sflocal/sunland/sun_hm.htm
[2934] http://www.consumerenergycenter.org/homeandwork/homes/inside/heatandcool/thermostats.html