Quantcast TEMPERATURE INVERSION

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
2-35 Figure 2-24.—Rf energy losses from scattering. Fog In the discussion of attenuation, fog may be considered as another form of rain. Since fog remains suspended in the atmosphere, the attenuation is determined by the quantity of water per unit volume and by the size of the droplets. Attenuation because of fog is of minor importance at frequencies lower than 2 gigahertz. However, fog can cause serious attenuation by absorption, at frequencies above 2 gigahertz. Snow The scattering effect because of snow is difficult to compute because of irregular sizes and shapes of the flakes. While information on the attenuating effect of snow is limited, scientists assume that attenuation from snow is less than from rain falling at an equal rate. This assumption is borne out by the fact that the density of rain is eight times the density of snow. As a result, rain falling at 1 inch per hour would have more water per cubic inch than snow falling at the same rate. Hail Attenuation by hail is determined by the size of the stones and their density. Attenuation of radio waves by scattering because of hailstones is considerably less than by rain. TEMPERATURE INVERSION Under normal atmospheric conditions, the warmest air is found near the surface of the Earth. The air gradually becomes cooler as altitude increases. At times, however, an unusual situation develops in which layers of warm air are formed above layers of cool air. This condition is known as TEMPERATURE INVERSION. These temperature inversions cause channels, or ducts, of cool air to be sandwiched between the surface of the Earth and a layer of warm air, or between two layers of warm air. If a transmitting antenna extends into such a duct of cool air, or if the radio wave enters the duct at a very low angle of incidence, vhf and uhf transmissions may be propagated far beyond normal line-of-sight distances. When ducts are present as a result of temperature inversions, good reception of vhf and uhf television signals from a station located hundreds of miles away is not unusual. These long


Electrical News
What Drove CES 2015 Innovation? IP and IP Subsystems
How do we manage all those blocks in an age...
eetimes.com
What Drove CES 2015 Innovation? IP and IP Subsystems
How do we manage all those blocks in an age...
eetimes.com
The Problem with Big Data
There is a lot of potential in Big Data, but...
eetimes.com
UMC Boosts Capex to Capture More 28nm Orders
UMC's large capex increase to capture more 28nm orders indicates...
eetimes.com
Moore's Law Cover Human Progress
Can a Moore's-like law be applied to anything? Where there...
eetimes.com
Quantum Entanglement Now On-a-Chip
Uncrackable encryption and quantum computers enabled by tiny 20 micron...
eetimes.com
Patent Law's Global Grey Areas
Patent law has unresolved grey areas when it comes to...
eetimes.com
TSVs to Split More Chips: Re-Integration is the Focus
At the 3D TSV summit, the speakers agreed on one...
eetimes.com
Startup Casts a Better IoT Network
Startup IoT Freeway claims it has a better wireless network...
eetimes.com
Open Office: Your Fart is My Problem
Open offices are the future. What a shame....
eetimes.com
Open Office: Your Fart is My Problem
Open offices are the future. What a shame....
eetimes.com
Configuration Tools Simplify MCU Setup
Graphical tools supporting developers in configuring complex MCU peripheral sets...
eetimes.com
Is Freescale Out of the Woods?
Freescale Semiconductor, burdened by large debt repayments since it was...
eetimes.com
EEVblog #709 – EDC 4601 AC Voltage Standard Teardown
Dave does some performance checks and then tears down a...
eevblog.com
iPhone Dials Up Record Apple Sales
Apple announced record financial results for the first quarter of...
eetimes.com
Fried Cable Sparked EE Profession
The electrical engineering profession was sparked in the late 1800s...
eetimes.com
2014: A Monumental Year for Cyber Attacks
As consumer and industrial IoT adoption rises, so does the...
eetimes.com
Brief Takes: Tech Stories You Should Know About
Here are 5 quick reads to catch you up with...
eetimes.com
Co-Robots Working Alongside People
Robots can work alongside people helping them without danger of...
eetimes.com
IoT Landscape Needs Mapping
In the first of a series of blogs on the...
eetimes.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +