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Talk:American Radio Relay League

2010-02-23T17:30:10Z

Aa6e: New page: Do we really want a list of trademarks for ARRL? --~~~~

Do we really want a list of trademarks for ARRL? --[[User:Aa6e|Aa6e]] 11:30, 23 February 2010 (CST)

American Radio Relay League

2010-02-23T17:29:21Z

Aa6e: Add new "national association..." name

The '''American Radio Relay League (ARRL)''' (also known as "ARRL, The National Association for Amateur Radio") was founded in May 1914 by US industrialist Hiram Percy Maxim (W1AW, SK) as the national membership association for US radio amateurs. The organisation now claims over 150 thousand members and a staff of over one hundred people.

The ARRL operates a [[QSL|QSL bureau]], advocates for the interests of radio amateurs with FCC and other governmental bodies, operates radio station W1AW in Newington, Connecticut and offers an assortment of radio-related publications and award programmes.

== Publications ==
ARRL publishes the magazines

* [http://www.arrl.org/qst QST] (monthly, general amateur interest)
* [http://www.arrl.org/qex QEX] (bi-monthly, "forum for communications experimenters")
* [http://www.arrl.org/NCJ National Contest Journal] (bi-monthly, contesting operation and station tips)

ARRL publishes a wide range of books and operating aids. Among the best known are:

* The ARRL Handbook for Radio Communications, updated most years since 1926. (Formerly published under several titles, such as The Radio Amateurs' Handbook)
* ARRL [[Antenna]] Book, published in many editions since 1939

Current publications are available from the [http://www.arrl.org/catalog ARRL Products Catalog] and booksellers.

== Awards ==
The ARRL operates the Logbook of the World (LotW) online QSL server and offers various awards, including:
* WAS (Worked All States)
* WAC (Worked All Continents)
* [[DXCC]] (DX Century Club, one hundred countries or 'entities' worked)

== Trademarks ==
ARRL, THE NATIONAL ASSOCIATION FOR AMATEUR RADIO holds US registered trademarks on the following names or logos:
* A R R L
* ARES / AMATEUR RADIO EMERGENCY SERVICE
* LOTW / LOGBOOK OF THE WORLD
* NCJ / NATIONAL CONTEST JOURNAL
* QST
* REPEATER DIRECTORY
* DXCC
* VUCC

== External link ==
* http://www.arrl.org

{{organisations}}

American Radio Relay League

2010-02-23T17:24:39Z

Aa6e: /* Publications */ Tighten up and refer to ARRL web resources.

The '''American Radio Relay League (ARRL)''' was founded in May 1914 by US industrialist Hiram Percy Maxim (W1AW, SK) as the national membership association for US radio amateurs. The organisation now claims over 150 thousand members and a staff of over one hundred people.

The ARRL operates a [[QSL|QSL bureau]], advocates for the interests of radio amateurs with FCC and other governmental bodies, operates radio station W1AW in Newington, Connecticut and offers an assortment of radio-related publications and award programmes.

== Publications ==
ARRL publishes the magazines

* [http://www.arrl.org/qst QST] (monthly, general amateur interest)
* [http://www.arrl.org/qex QEX] (bi-monthly, "forum for communications experimenters")
* [http://www.arrl.org/NCJ National Contest Journal] (bi-monthly, contesting operation and station tips)

ARRL publishes a wide range of books and operating aids. Among the best known are:

* The ARRL Handbook for Radio Communications, updated most years since 1926. (Formerly published under several titles, such as The Radio Amateurs' Handbook)
* ARRL [[Antenna]] Book, published in many editions since 1939

Current publications are available from the [http://www.arrl.org/catalog ARRL Products Catalog] and booksellers.

== Awards ==
The ARRL operates the Logbook of the World (LotW) online QSL server and offers various awards, including:
* WAS (Worked All States)
* WAC (Worked All Continents)
* [[DXCC]] (DX Century Club, one hundred countries or 'entities' worked)

== Trademarks ==
ARRL, THE NATIONAL ASSOCIATION FOR AMATEUR RADIO holds US registered trademarks on the following names or logos:
* A R R L
* ARES / AMATEUR RADIO EMERGENCY SERVICE
* LOTW / LOGBOOK OF THE WORLD
* NCJ / NATIONAL CONTEST JOURNAL
* QST
* REPEATER DIRECTORY
* DXCC
* VUCC

== External link ==
* http://www.arrl.org

{{organisations}}

Complex number

2010-02-20T01:42:55Z

Aa6e:

A complex number is an ordered pair of real numbers. (A real number may take any value from -infinity to +infinity. Real numbers are commonly represented as points on the "real number line", i.e., a straight line of infinite length.)

The two components of a complex number (a,b) are the real part (a) and the imaginary part (b). Complex numbers may be represented as points on an infinite two-dimensional plane surface, with the real part as the "X" coordinate and the imaginary part as the "Y" coordinate.

The operations of addition and multiplication are defined for complex numbers:

(a,b) + (c,d) = (a+c, b+d), and

(a,b) x (c,d) = (ac-bd, ad+bc)

Complex numbers may also be represented using "i" (or "j" in engineering contexts). The symbol "i" refers the the complex number (0,1). If "i" is interpreted as the square root of -1, we can write complex numbers in the form

(a,b) = a + ib

The addition and multiplication operators work out in a simple way, if we remember to collect real and imaginary terms and remember that i x i = -1. Thus,

(a+ib) x (c+id) = ac+aid+ibc+iibd = ac+i(ad+bc)+(-1)bd = ac-bd + i(ad+bc)

Complex numbers are often used in scientific and engineering applications to describe systems where amplitude and phase of a narrow band signal are important. If V = (re, im) is a complex value (say voltage), the amplitude and phase of V are

<math>Amp = \sqrt{re^2 + im^2}\,</math>

and

<math>Phase = \arctan \big(\frac{im}{re}\big)</math>

A sinusoidal voltage with frequency <math>\omega = 2 \pi F</math> may be considered to be the real part of a complex voltage

<math>V(t) = V_0\, \exp(j \omega t+ j\phi) = V_0\, ( \cos(\omega t+\phi) + j \sin(\omega t+\phi)\,)</math>

with amplitude <math>V_0</math> and phase <math>\phi</math>.

Complex number

2010-02-20T00:13:25Z

Aa6e: New page: A complex number is an ordered pair of real numbers. (A real number may take any value from -infinity to +infinity. Real numbers are commonly represented as points on the "real number li...

A complex number is an ordered pair of real numbers. (A real number may take any value from -infinity to +infinity. Real numbers are commonly represented as points on the "real number line", i.e., a straight line of infinite length.)

The two components of a complex number (a,b) are the real part (a) and the imaginary part (b). Complex numbers may be represented as points on an infinite two-dimensional plane surface, with the real part as the "X" coordinate and the imaginary part as the "Y" coordinate.

The operations of addition and multiplication are defined for complex numbers:

(a,b) + (c,d) = (a+c, b+d), and
(a,b) x (c,d) = (ac-bd, ad+bc)

Complex numbers may also be represented using "i" (or "j" in engineering contexts). The symbol "i" refers the the complex number (0,1). If "i" is interpreted as the square root of -1, we can write complex numbers in the form

(a,b) = a + ib

The addition and multiplication operators work out in a simple way, if we remember to collect real and imaginary terms and remember that i x i = -1. Thus,

(a+ib) x (c+id) = ac+aid+ibc+iibd = ac+i(ad+bc)+(-1)bd = ac-bd + i(ad+bc)

Complex numbers are often used in scientific and engineering applications to describe systems where amplitude and phase of a narrow band signal are important. If V = (v1, v2) is a complex value (say voltage), the amplitude and phase of V are

Amp = sqrt(v1**2 + v2**2) and Phase = arctan(v2/v1).