You do not only want to use your computer for plays? Then I would like to tell you a few programs, with which you can use him also for the amateur radio.
 
Measuring instruments/Inspection devices
 

 
Schematic circuit diagrams/Printed circuit boards
 

 
Search machines
 

 
Translations
 

 
Aid
 

 
Callsign directories
 
Do you want to know, who is the operator or the QSL manager for a callsign? Some callsign directories are here disposable.

 
WWW
 
Although some radio amateurs avoid this medium, I regard it with correct application as very useful means of communication. Therefore I would like to call you also some useful programs for it.

Spectrogram
 
The program represents the AF spectrum. It needs only a sound card. I use it very gladly for measuring on IF/AF filter. Only a source of noise to the receiver input, the AF output to the sound card and already I can see (!), how the filter operates.
Mr. Richard Horne, the creator of this program, gave me in November 2005 the permission to put the last freeware version 5.1.7 (EXE, 294 KB) on my webpage. Thank you Mr. Horne! A newer shareware version with more features was available on the webpage of Visualization Software LLC.
Addendum: As from April 2008 (for a short time) was also the version 16.0 available as freeware. It offered more features than the old freeware version and was available on the the above-mentioned webpage.

Spectrum Lab by Wolfgang Büscher, DL4YHF
 
The program Spectrum Lab represents the AF spectrum as waterfall diagramm and/or "fidgety" line. It needs only a sound card. The features of this program are manifoldly, but with experiments you can handle it without reading the help file.

sPlan by Abacom
 
With sPlan by Abacom you can fast design schematic circuit diagrams on your Windows PC. A extensive and easy to extensible component library will help you thereby. Within minutes you will understand the handling of the program.
There is a demo version. This version have some restrictions, but nevertheless you can get a good impression of the program features.

Sprint-Layout by Abacom
 
With the easy program Sprint-Layout by Abacom you can easy design single-sided and double-sided printed circuit boards on your Windows PC. The handling of the program is learnable within minutes.
There is a demo version. This version have some restrictions, but nevertheless you can get a good impression of the program features.

Altavista
 
Altavista is not so well-known like (beeeeeeep), but the best search mashine which I know. There are not broken links and the robot knows also my small webpages.

Babelfish
 
By the search maschine Altavista was developed with Babelfish a translation tool for texts and whole webpage, which is settled now with Yahoo.

Azimuth by Tony Field, VE6YP
 
The program Azimuth represents the world (or a window of it) in azimuth or classic projection. A simple way, to print your own Beam maps for each point of the earth. An alternative with more features is AZMap.

Mini Ring Core Calculator by Wilfried Burmeister, DL5SWB
 
The Freeware Windows program Mini Ring Core Calculator makes ist easy to computate the inductance, the number of turns, the resistance, the necessary wire length and other technical features of coils. Withal both different core types/sizes and the construction of air coiles are supported. The operation of the program is alternatively possible in English, German or French.

AZMap by Paul Burton, AA6Z
 
The program AZMap represents the world in azimuth projection. A simple way, to print your own Beam maps for each point of the earth. It's possible to display among other things also the aurora zones and the night side of the earth, like to see in the screenshot. An alternative with less features is Azimuth.

NCDXF/IARU International Beacon Network
 
The NCDXF/IARU International Beacon Network with its beacons is a good aid to estimate the propagation conditions. The project covers 18 beacons, which are developed in all parts of the earth. The beacons send cyclically all 3 minutes. The callsign is always send with 100 W. Then four long dashes of 1 s follow, with which the output is lowered from 100 W first to 10 W then to 1 W and at the end to 0.1 W. Than the next beacon follows.
If I switch on my station, I observe only once these beacons. Because its transmit also with 10 and 1 W I can take a good judgement over the conditions and whether staying on the bands is meaningful or not.
The time, when which beacon sends, indicates a beacon schedule. Thus I can assign still callsign signals, which I heard not completely.
 Background picture: NASA/Goddard Space Flight Center (Source: Wikipedia)

VOACAP
 
The online-tool VOACAP (Voice of America Coverage Analysis Program) is usuable for propagation predictions for shortwave connections in 2 versions. With the first one, the VOACAP Online Coverage Maps, you can receive predigtions for the whole world. The second one, the VOACAP Online Point-to-Point Predictions, is usuable, if the propagation for a point-to-point connection should be estimated. Booth parts are qualified for the frequency area 3-30 MHz.

HamQTH by Petr Hlozek, OK2CQR
 
If you are looking for an address of an international ham radio station, so HamQTH offers informations, which are visible completely also without a registration. Each ham radio operator determines, which informations are presented. It's possible to present only the name and the QTH, but also addresses for snail-mail, the webpage or email and so on. Who want to be deleted from the directory sends only an email to the owner.

QRZ.COM
 
If you look for the address of an international ham radio station, then QRZ.COM offers a comprehensive database with information. The informations should be correctly, because they are entered there by each ham radio amateur themself and also hopefully kept up to date. There is a disadvantage however: In order to be able to see all Informations, you must have registered yourself and logged in before. But you can copy the address afterwards also from the webpage in order to paste it for example into the write program for labels.

Buckmaster
 
If you look for the address of an international ham radio station, then also Buckmaster offers a comprehensive data base with information. The information should be correctly, because also they are entered there by each ham radio amateur themself and also hopefully kept up to date. The address is immediately visible. If you want do see the email address, you have registered yourself before and logged in. The address is copyable only as picture of the webpage. But each write program for labels permits also to insert pictures, so you do not have to type the address.

SelfHTML
 
You want to design your own webpages? There are an extensive and free documentation named SelfHTML (in German) about the design of webpages, which Stefan Münz of TeamOne wrote. Without that freeware my webpages would not look like it does now. The best source of knowledge I know!

MailWasher Free by Mailwasher and MailWasher Pro by Firetrust
 
Spam is every bit of unwelcome and circulars in your post box. Fortunately there are ways to decrease or eliminate the amount of spam you receive in your daily e-mail. MailWasher Free by Mailwasher is the free avaiable version. Although this version is no longer continued to develop, it is fully usable for the spam defense. However the free version can supervise only one email account.
The follower MailWasher Pro from Firetrust develops constantly and possesses more possibilities than the free version. It is 30 days free for use, but the money for registration is profitable.

AntiVir
 
In the meantime there are a lot of computer virus - and each day there are more. That's why it is importent, to protect oneself effective against digital attacks. An easy method for it is the AntiVir Personal Edition by Avira, which is free for personal use.

Firefox
 
If you look for a web browser, which is safe and nevertheless fast, then regard once the free Firefox. It comes from the house Mozilla and is available for computers with the operating systems Windows, OS X and Linux. The standard design can be extended by various add-ons. In addition different language modules are offered.

Thunderbird
 
Before the next thunderstorm draws up while handling your past e-mail program, you should test the free Thunderbird. It comes from the house Mozilla and is available for computers with the operating systems Windows, OS X and Linux. It administers several accounts independently and makes the problem-free import of messages from the program used so far. In addition it is available with different language modules.

Formmailer
 
The delivery of the in my Guestbook entered texts to me took place for many years by e-mail via the for private people free service by Formmailer (in German).
Tanslated quotation from the Formmailer webpage: "The Formmailer ... serves for comfortable dispatching of e-mails, which are produced from HTML forms. The target group are users like private people or small companies, who do not want to have an access to CGI scripts or not want to follow up with programming and mechanism of such scripts. The commercial use of the Formmailers is chargeable! Commercial users of the Formmailers can be set let themselves messages against a page fee also by fax."

Formpost
 
The delivery of the in my Guestbook entered texts to me takes place furthermore by e-mail. Because I still do not have the option to host CGI or PHP scripts on my webpages, I use now the service by Formpost (in German).
Formpost makes with "FreeForm" the variant of a formular mailer avaiable, which is sufficient for private users like me. Who wants more, who can switch also to "PayForm" or "PayForm DP", which offer more features.

Validator by W3 Consortium
 
Especially one who designed his webpages without any automats will also want to know after completed work, whether the provided HTML text is also error free. Because if the rules set up by the W3 consortium are only kept, the pages are indicated in such a way by the different browsers, how it also intended the author. Some browsers tolerate also small errors, but one should designed webpages without errors. You can use for HTML files the Makeup Validator Service. The procedure to check the contingently used CSS files is identically. This time you use entirely the CSS Validation Service.
The checks functions as follows: Go to the respective Validator, enter the complete address (with http://) of the webpage and cklick "Check". If all is correct, this indicated by a green symbol. Otherwise the symbol is red, the number of the errors/warnings is displayed and the affected positions will be displayed.