Web, Wi-Fi, Wireless and PC Technology 24.1

Web, Wi-Fi, Wirelessand PC Technology

Chapter 24

With the Internet and the Personal Com-puter (PC) more commonplace in homes andham shacks around the world, some fear itmay actually destroy Amateur Radio! Theirreasoning is that increasingly powerful PCs,coupled with access to the Internet or world-wide web (www), will primarily divertyouth from the lure, mystique and magic ofradio. Could an advancement in technologywith the corresponding economies-of-scaleactually deprive Amateur Radio of an influxof fresh, young operators and enthusiasts?

The PC and its Internet link to the worldaround us have surely changed many

lifestyles young and old and those inbetween. But far from destroying Ama-teur Radio as we know it, these technolo-gies have greatly enhanced and improvedthe ham radio experience of countlessoperators! Many hams with an interest orpassion in homebrewing, DXing, contest-ing, and the wide variety of other relatedareas of interest now take for grantednearly instantaneous access to informa-tion and interest-related Web sites. Com-puters and modems are sometimes usedfor the operation of various modes, andcan also be a primary part of the actual

ham radio equipment (e.g., a transceiveror receiver).

In this chapter, in addition to coveringmany of these exciting areas describedabove, we will also review the personal/commercial wireless world around us thatis extraneous to ham frequencies, equip-ment or operation. This chapter was writ-ten by Donald R. Greenbaum, N1DG, andDana G. Reed, W1LC. It also includescontributions from John J. Champa,K8OCL, Reed E. Fisher, W2CQH,Howard S. Huntington, K9KM, andRonnie P. Milione, KB2UAN.

The World Wide Web (www) The InternetSEARCH ENGINES

The Internet encompasses millions andmillions of pages of information. There issimply too much information on the subjectof ham radio to find without properly usingsearch engines. There are many related hamsites, but the most popular are listed in thesidebar A Hams Guide to Useful InternetSites. In any event, the most popular searchengines are Google, Yahoo, Ask Jeeves,Alta Vista, Dogpile, Look Smart, Overture,Teoma and Find What.

The secret to a successful search is to bespecific by limiting the results or hits.Simply typing "ham radio" as the topic ofinterest to you is not sufficient. A query onham yielded links to Web sites mention-ing ham radio, ham (the food) and otherhits totaling over 7 million pages! A morespecific search of ham radio reduced thepage count to 1.7 million pages, still toonumerous to be helpful. Narrowing andrefining your search is as simple as adding

Search Engines Electronic Parts andCross Referencing

A QRP list member was trying to search, or cross reference, a semicon-ductor in Google, but without success. He had probably only entered theexact part number. The part was described as possibly of one family ofsemiconductor, but apparently in Google he used the part numberIRF331A which indeed comes up blank.

However, a knowledge of manufacturing prefixes or numbering systemsused for semiconductors or other components can be very valuable.Originally, IRF was the prefix for International Semiconductor Parts.Entering that in Google.com, I came up with a Web page: www.irf.com.From there, I came to a search engine on the page that eventually led totheir cross reference guide and the fact that the IRF331A can possiblybe replaced (depending on the application) by the IRF330. However, anupgraded part is the IRF440, or the 2N6760.

Knowing a general supplier of replacement semiconductors, my next stop had this not worked out would have been www.NTE.com. The mainpoint here is to study distributors catalogs, for knowledge of part-number-ing conventions for whatever electronics you might need. Get to knowcompany logos that are applied to parts as these will shorten yoursearches if the company still exists, using that logo. For the totally unfamil-iar part, a logo can be very helpful to focus your search.Stuart Rohre,K5KVH

24.2 Chapter 24

more words. This is called using key-words, and choosing them wisely will re-duce the page count to manageable levels.Ham radio software reduces our search to427,000 pages while ham radio dsp soft-ware reduces it to 18,600 pages; you cankeep refining your search by adding key-words, and there is no need to include theword and between the words.

Another way to reduce hits on yoursearch is to exclude categories. For in-stance, if you want to search for ham youcan exclude the food ham by ham food.If you want to search for an item but onlywant to search for it on a specific Website, you can do that too. For instance, tolook on the ARRLWeb you can do license

renewal site: www.arrl.org.Searching for specific part numbers for

your do-it-yourself projects is similarlyeasy. In the PC Technology section of thischapter we discuss isolation transformers.A search for 273-1374 brings you rightinto the RadioShack catalog, as well aspages on how to build other projects withit. There is a fine line for being too spe-cific in searches. Sometimes the part num-ber can be too exact, and adding either amanufacturer or looking up the descrip-tion of isolation transformers are abroader alternative that will help if thespecific part search comes up negative.See also the sidebar Search Engines Electronic Parts and Cross Referencing.

VOICE OVER INTERNETPROTOCOL VoIP

Like our airwaves, the Internet can carryour transmissions over great distances. Un-like ham radio, the Internet is only digital. Ifwe are use voice or video over that mediumthose modes must be converted into thatdigital format before sending and convertedback to analog upon receipt. Two softwarepackages have emerged to allow hams toconverse over the Internet in what is knownas Voice over Internet Protocol, or VoIP.ARRL offers a new publication titled VoIP:Internet Linking for Radio Amateurs. Thebook discusses in great detail the brief out-line of the topic that follows.1

EcholinkRecognizing the growing use of the

Internet by hams, K1RFD wrote a soft-ware program called Echolink. Now evenantenna-restricted hams can enjoy the funwith a computer, a microphone and anInternet connection. You can connect viaEcholink to other licensed hams on comput-ers, mobiles transmitting through repeaterslinked to the Internet via connected VHFrepeaters and even nodes connected via HF.There are more than 120,000 registered us-ers in 147 countries worldwide. There arealso conference nodes, some specific toother hobbies such as aviation. It is the ulti-mate party line encompassing computers,radio and the Internet. Like radio, it is non-duplex; both stations cannot talk at once. Thesoftware is free (you must be licensed) andis downloadable from www.echolink.org.The software is very user friendly, and allcontrol features are click-of-a-mouse en-abled. The only requirement of your PC is asound card and microphone.

IRLPUnlike Echolink, which allows two

hams to communicate without having aradio, IRLP takes a different approach toVoIP. David Cameron, VE7LTD, de-signed the Internet Radio Linking Project(IRLP). As he says on his Web site, hedesigned the software to provide a simpleand easy system to link radio systems to-gether using the Internet as the communi-cations backbone.

IRLP users do not need to own com-puters. They simply access the networknodes using VHF or UHF FM trans-ceivers.

The IRLP network is Linux based andrequires a Linux-based Pentium PC at eachnode running Speak Freely software, an in-terface card (purchased inexpensively fromVE7LTD), your radio and a sound card. Thesound card takes the analog audio from theradio, converts it to compressed digitalpackets and sends short streams over the

A HAMS GUIDE TO USEFUL INTERNET SITESSince website URLs change so often, any attempt to present a comprehen-

sive list here would be out of date by the time of publication. Accordingly, wehave instead listed general ham-related sites that contain current links tomany of the specific radio sites on the Web:

ARRL: www.arrl.org Where else would you go for ham radio news?

AC6V: www.ac6v.com/ Rod has links to over 6,000 other radio relatedsites covering all topics imaginable.

AA1V: www.goldtel.net/aa1v/ Don has the usual DX links plus some prettygood NASA links not found on other sites.

DX Zone: www.dxzone.com/ A good commercially-run site that is well laidout providing 4500 links to other commercial and private ham run sites.

425 DX News: www.425dxn.org/ Good Italian non-commercial site for DXNews and links to DX-related sites.

K4UTE: www.nfdxa.com/K4UTE/K4UTE.HTML One of the best sourcesof QSL routes and links to other DX-related activities.

NG3K: www.ng3k.com/Misc/adxo.html Want to know whos going whereand the link to their Web site? Since 1996, Bill has been keeping track ofthese things on this Web site and has everything archived for searching.

QSL.NET: www.qsl.net/master.htm Al, K3TKJ, provides free hosting tothousands of hams for radio-related Web pages.

K1BV Awards Directory: www.dxawards.com/ Are you into wallpaper?Ted has one of the best sites for award information and links to thoseoffering them.

MODS: www.mods.dk/ Modifying your radio? Find hundreds of linkscompiled over the last eight years by Erik, OZ2AEP.

Linux Ham Radio Software Directory: radio.linux.org.au/ Do you preferLinux to Windows? This site lists Perl scripts ranging from modeling antennasto European Microwave Beacon propagation forecasting.

Satellite Tracking Software: www.david-taylor.pwp.blueyonder.co.uk/software/wxtrack.htm

QSL Museum: www.hamgallery.com/ In addition to one of the mostcomplete online QSL collections, Tom (K8PX) has one of the more completeham radio link sites on the web.

Web, Wi-Fi, Wireless and PC Technology 24.3

Internet to the connected nodes via the inter-face card. The control software controls thepackets along with continuous tone codedsub audible squelch signals (CTCSS) to start

and stop the streams. CTCSS is also used bythe transmitting user to pass commands tothe nodes for the information as to whichnode a user wants to connect to, start andstop the connection and a host of othersettable parameters to control the process.Streams can be sent to one or many nodes.

The software, interface cards and allmanuals are available from the IRLPwebsite at www.irlp.net

PROPAGATION FORCASTINGOne of the most valuable pieces of in-

formation available on the Web is the vari-ous real time propagation statistics andtools. Current gray-line paths are vital tothe LF operator. MUF values are helpfulto HF operators. Current observed sunspotactivity, solar storm indexes, etc. are allposted on various ham and governmentWeb sites giving the Internet-connectedham useful tools to know where the bestpaths to the DX are. Current solar fluxnumbers are published by the CanadianSpace Agency as monitored at itsPenticton Observatory: www.drao-ofr.hia-iha.nrc-cnrc.gc.ca/icarus/www/current_flux.shtml

Since Auroral activity is harmful to HFtransmissions over the globe, NOAA pro-vides both North and South Pole real timeauroral maps: sec.noaa.gov/pmap/gif/pmapN.gif. A recent North Pole image isshown in Fig 24.1.

Knowing which frequencies are usablein real time is also as handy a propagation

Fig 24.1 NOAA North Pole map imageof recent, real-time auroral activity.

Fig 24.2 Solar Terrestrial Dispatchgraphic depicting frequency usability inreal time.

tool as a ham could want. As shown inFig 24.2, a real-time graphic can be foundat the Solar Terrestrial Dispatch Web site:www.spacew.com/www/realtime.html.

VIRUS PROTECTION ANDFIREWALLS

Lastly, no Internet user should be con-necting to the Web without up-to-date virusprotection. Norton Antivirus and McAfeeare the two most popular commercial prod-ucts. There are also some shareware prod-ucts available. However, virus protectionalone does not offer full protection fromintruders. Hams increase the risk of beinginfected by opening ports to allow IRLP,Telnet, Instant Messenger, VoIP, or FTPapplications. The solution is installing oneof two types of firewalls. The first is an in-expensive software-based firewall fromNorton or McAfee for under $50. They de-tect both internal and external attempts tocompromise your personal computer (PC).The more expensive but more capable solu-tion is a hardware-based device commonlyknown as a Firewall Appliance. In additionto the simple intruder detection found infirewall software, they contain an intruderprevention system, the ability to connectmultiple PCs (as a router or switch), monitorability on all traffic in and out of the net-work, open secure ports (VPN) and auto-matically obtain updates to firmware.

Notes1See ARRLWeb at www.arrl.org/shop;

Order no. 9264.

Wi-Fi GlossaryAccess Point (AP) A wireless bridg-

ing device that connects 802.11 stations toshared resources and a wired network suchas the Internet.

Ad Hoc In wireless LAN (WLAN)networks this is a direct wireless connec-tion between two laptop computers with-out the use of an AP.

AP Access point.Carrier Sense Multiple Access / Colli-

sion Avoidance (CSMA/CA) The wire-less method that tries to avoid simultaneousaccess or collisions by not transmitting, ifanother signal is detected on the same fre-quency channel.

Direct-Sequence Spread Spectrum

(DSSS) The type of modulation used in802.11b that is capable of maximum half-duplex data speeds of 11 Mbps.

Frequency Hopping Spread Spectrum(FHSP) A type of modulation used inearly 802.11 devices that uses a time-var-ied narrow signal to spread the signal overa wide band. Maximum half-duplex datarate is 2 Mbps.

Institute of Electrical and ElectronicsEngineers (IEEE) The professionalstandards setting organization for data net-working devices.

Orthogonal Frequency Division Mul-tiplexing (OFDM) A type of modula-tion that splits a wide frequency band into

many narrow frequency bands. Both802.11a and 802.11g use OFDM.

Service Set Identity (SSID) Theidentification for an AP. It is transmittedcontinuously in the form of a beacon.

Wired Equivalent Privacy (WEP) Astandard for providing minimal privacy ofwireless LAN communication by encrypt-ing individual data frames.

Wireless Fidelity (Wi-Fi) The Wire-less Ethernet Compatibility Alliance certi-fication program to ensure that equipmentclaiming to be in compliance with 802.11standards is truly interoperable. The termWi-Fi5 is sometimes applied to 802.11aequipment that operates on the 5-GHz band.

Wireless Fidelity (Wi-Fi)COMPUTER CONNECTIONS BYRADIO

Wireless local area networks (WLAN)using spread spectrum transmit in the902-MHz range (802.11), in the 2.4-GHz

frequency range (802.11b and 802.11g),and in the 5-GHz frequency range(802.11a). Combining spread spectrumtransmissions characteristics with a lowpower output (30 to 100-mW range) means

it is highly unlikely that one spread spec-trum network user will interfere with an-other. Spread spectrum transmissionsdistribute or spread a radio signal overa broad frequency range. There are vari-

24.4 Chapter 24

ous techniques for doing this spreading.The older WLAN systems operate in the

902-MHz range based on the IEEE 802.11standard and use frequency hoppingspread spectrum modulation, or FHSS.This modulation technique uses what iscalled a predetermined pseudo-randomsequence to transmit data. This pseudo-random sequence is actually a predeter-mined digital signal pattern that placesdata on a combination of frequenciesacross the entire spread spectrum channel.The receiving station must know thespecific signal pattern used by the trans-mitting station to decode the data. Theseearly 802.11 systems generally operatedwith slightly higher power (250 mW) butat much slower data rates of typically2 Mbps.

New-generation WLANThe first of the new generation of

WLAN systems is based on the IEEE802.11b standard and use a modulationtechnique known as direct-sequencespread spectrum, or DSSS. This modula-tion technique achieves higher data ratesby using a different pseudo-random codeknown as a Complimentary Sequence. The8-bit Complimentary Sequence can en-code 2 bits of data for the 5.5 Mbps datarate or 6 bits of data for the 11 Mbps datarate. This is known as ComplimentaryCode Keying (CCK).

The latest generation of WLAN devices

are based the same type of modulation,Orthogonal Frequency Division Multi-plexing (OFDM) but operate on differentfrequency bands. OFDM provides itsspreading function by transmitting thedata simultaneously on multiple carriers.802.11g operating in the 2.4-GHz rangeand 802.11a operating in the 5-GHz rangeboth specify 20-MHz wide channels with52 carriers spaced every 312.5 kHz.OFDM radios can be used to transmitdata rates of 6, 9, 12, 18, 24, 36, 48 and54 Mbps.

The WLAN AdvantageThe main advantage of WLAN systems

is that the laptop PC users are not tied to anRJ-45 type of wall outlet. At home theycan roam between the home office and thepatio. At work, they can move with easebetween an office and a conference room,for example. There is a significant eco-nomic advantage for businesses re-locat-ing office areas. With the use of WLANtechnology, it is not necessary to spendthe time and money to rewire an entirefloor or building. These small radio de-vices with their small antennas and lowpower can readily transmit through sev-eral layers of drywall. If more than oneaccess point, or AP, is required to coverthe business area, several AP devices canall be linked together by putting them inthe same virtual LAN in the wired net-work. Consequently, rather than having to

wire each individual office and conferenceroom, only the various AP nodes need tobe wired together. This can produce a hugesavings in time and expense.

WLAN SecurityAlthough the majority of WLAN oper-

ate in the open mode allowing anyone inthe area convenient access the network,often a minimum level of information se-curity is desirable. This can be providedby using a WLAN encryption protocolbuilt into the equipment called WiredEquivalent Privacy, or WEP. For thosesituations requiring a higher level of secu-rity, most commercial firms simply re-employ their virtual private network(VPN) or tunneling strategy commonlyused to allow secure network remote ac-cess for mobile workers and teleworkers.However, in the case of WLAN use, extrasteps need to be taken to ensure that theVPN user ID and password are not beingwirelessly transmitted in the clear withoutsome form of encryption. A new WLANsecurity standard called IEEE 802.1x at-tempts to address this need but is currentlyplagued with interoperability issues.

Wi-Fi systems being used in AmateurRadio applications are typically referredto as High Speed Multimedia (HSMM),and these techniques are discussed in de-tail in the HSMM section of the Modesand Modulation Sources chapter of thisHandbook.

Wireless Technology GlossaryAMPS (Advanced Mobile Phone Ser-

vice) First standardized cellular servicein the world, released in 1983. Uses the800-900 MHz frequency band.

Analog A signal that can vary con-tinuously between a maximum and mini-mum value. For example, the voicevoltage waveform from the output of amicrophone is analog. RF voltage wave-forms (as those from AM, FM and SSBtransmitters) are also analog.

Cap Code A specific address en-coded into both a data transmission andthe intended receiving equipment so thereceiving equipment can discriminateagainst unintended or unwanted messages.

CDMA (Code Division Multiple Ac-cess) A digital radio system that sepa-rates users by digital codes.

Cellular Characteristic of or pertain-ing to a system of wireless communica-tion made up of many individual cell units.The term itself is derived from the typicalgeographic honeycomb shape of the areas

into which a coverage region is divided.CELP (Codebook Excited Linear

Predictive coding) A type of low-bit-rate voice coder that emulates a singlehuman voice tract. Details can be found inRef. 3 at the end of this chapter.

CSMA/CD (Carrier Sense MultipleAccess / Collision Detection) A set ofrules that determine how network devicesrespond when two devices attempt to use adata channel simultaneously (called a colli-sion). After detecting a collision, a devicewaits a random delay time and then attemptsto re-transmit the message. If the devicedetects a collision again, it now waits twiceas long to try to re-transmit the message.

DHCP (Dynamic Host ConfigurationProtocol) An external assignmentmechanism that provides a care-of ad-dress to a mobile client (see also ForeignAgent).

Digital A signal that has only discretevalues, usually two (logic 1 and logic 0), thatchanges at predetermined intervals. The

value (e.g., voltage) present in a single timeperiod is called a bit. The number of bitstransferred per second is called the bit ratethat has units of bits per second (bit/s), orkilobits per second (kbit/s), etc.

E-mail Electronic mail sent and re-ceived via computers with modems.Transmission media can be existing tele-phone or other communication lines, wire-less, or not uncommonlyboth.

Encode The process whereby atransmission contains additional data orcode added to facilitate proper routing ofthe transmission to the desired point orpoints.

Encryption Technology used toform a secure channel between a wirelessclient and the server to support user au-thentication, data integrity, and data pri-vacy.

ESN (Electronic Serial Number) Amanufacturer-assigned identity containedin a data transmission from a call placed toverify that the hardware used belongs to a

Web, Wi-Fi, Wireless and PC Technology 24.5

valid cellular account.Ethernet A local-area network

(LAN) protocol. Ethernet uses a bus or startopology and supports data transfer ratesof 10 Mbit/s, 100 Mbit/s, 1 Gbit/s and10 Gbit/s. Ethernet uses the CSMA/CDaccess method to handle simultaneousdemands, and is one of the most widelyimplemented LAN standards.

FDMA (Frequency Division MultipleAccess) A radio system that separatesuser channels by frequency. AmateurRadio equipment presently uses FDMA.

Footprint The coverage area of anindividual cell.

Foreign Agent A special nodewhich is present on a foreign network andprovides mobility services to visitingmobile nodes.

GPS (Global Positioning System) A Dept. of Defense-developed, world-wide, satellite-based radio navigationsystem.

Handoff Process whereby a mobiletelephone network automatically transfersa call from cell to cellpossibly to an-other channelas a mobile crosses adja-cent cells.

Home Agent A host on a mobileshome network responsible for trapping itspackets, and forwarding them to themobiles present location.

LAN (Local Area Network) A com-puter network that spans a relatively smallarea. Most LANs are confined to a singlebuilding or group of buildings. However,one LAN can be connected to other LANsover any distance via telephone lines andradio waves. A system of LANs connectedin this way is called a wide-area network(WAN). Most LANs connect workstationsand personal computers. Each node (indi-vidual computer) in a LAN has its owncentral processing unit (CPU) with whichit executes programs, but it is also able toaccess data and devices anywhere on theLAN. This means that many users can shareexpensive devices, such as laser printers,as well as data. Users can also use the LANto communicate with each other, by send-ing e-mail or engaging in chat sessions.

Mobile Host Also known as a mo-bile node, this addressed entity in theMobile IP protocol roams between itshome network and foreign networks.

Mobile IP This mobile industry stan-dard enhances the IP protocol to remedyproblems associated with using the stan-dard TCP/IP with a mobile entity. It allowsfor transparent routing of IP datagrams tomobile hosts (nodes) on the Internet.

Modem A hardware device, eitherinternally or externally connected to a com-puter that provides a connection from thecomputer and some of its programs to alandline (phone or communications line).

Network Independence The abilityto roam among networks (e.g., BellSouthWireless Data Network, CDPD, Wire-less LAN, Ethernet), although tradition-ally accomplished using the same accessmedia such as SLIP, PPP, etc.

Node A unique host on a networksuch as a printer, computer device,handheld Personal Digital Assistant(PDA), or a mainframe.

PCMCIA (Personal ComputerMemory Card International Assoc-iation) An organization consisting ofsome 500 companies that has developed astandard for small, credit card-sized de-vices called PC Cards, originally designedfor adding memory to portable computers.

PDA (Personal Digital Assistant) A handheld device that functions as a per-sonal organizer. Many PDAs began aspen-based, i.e., using a writing stylusrather than a keyboard for input, thus uti-lizing handwriting recognition features.Some PDAs feature voice recognitiontechnologies. At present, most PDAs of-fer either a stylus or keyboard version.

POS (Point of Service) A gener-ation of narrowband digital, two-way,low-powered wireless services in the 800-900 MHz bands that will support con-firmed delivery of message, full two-waydata transfer, voice messaging and con-nectivity via the Internet.

PPP (Point-to-Point Protocol) Amethod of connecting a computer to theInternet. PPP is more stable than the olderSLIP protocol and provides error-check-ing features.

Remote Presence The ability to es-tablish remote network connections andstill appear to be connected to the homenetwork.

Security The ability to create securechannels for user authentication, data in-tegrity, and data privacy.

SLIP (Serial Line Internet Protocol) An older method of connecting a com-puter to the Internet. A more commonlyused method is PPP. SLIP is an older andsimpler protocol, but from a practical per-spective, theres not much difference be-tween connecting to the Internet via SLIPor PPP. In general, service providers onlyoffer one protocol, although some supportboth protocols.

TCP/IP (Transmission Control Pro-

tocol/Internet Protocol) The suite ofcommunications protocols used to con-nect hosts on the Internet. TCP/IP usesseveral protocols, the two main ones be-ing TCP and IP. TCP/IP is built into theUNIX operating system and is used by theInternet, making it the de facto standardfor transmitting data over networks. Evennetwork operating systems that have theirown protocols, such as Netware, also sup-port TCP/IP.

TDMA (Time Division MultipleAccess) A digital radio system thatseparates users by time.

Third Party Mobile IP An Internettechnology solution that provides bothwireless and wireline IP network and me-dia roaming/communications to bothIntranet and Internet services.

Throughput The amount of dataprocessed, or transferred from one placeto another in a specified amount of time.Data transfer rates for disk drives and net-works are measured in terms of through-put. Typically, throughput is measured inkbit/s, Mbit/s, and Gbit/s.

TIA (Telecommunications IndustryAssociation) Telecommunications In-dustry Association, 2500 Wilson Blvd,Arlington, VA 22001. On the web: www.tiaonline.org.

T1P1 The wireless group in Com-mittee T1. Alliance for Telecommunica-tions Industry Solutions, 122 G St. NW,Suite 500, Washington, DC 20005. On theweb: www.atis.org.

Virtual Private Network Networkcreated when a mobile user connects a dataterminal to a foreign network and estab-lishes a presence equivalent to a directconnection to the home network.

WAN (Wide Area Network) A com-puter network that spans a relatively largegeographical area. Typically, a WAN con-sists of two or more local-area networks(LANs). Computers connected to a wide-area network are often connected throughpublic networks such as the telephone sys-tem. They can also be connected throughleased lines or satellites. The largest WANin existence is the Internet.

Windows OS Microsoft WindowsOperating System.

Wireless Data Information or in-telligence, sent or received by wirelesstransmission/reception without the directaid of a landline.

WLAN (Wireless Local Area Network) A local-area network that uses high fre-quency radio waves rather than wires tocommunicate between nodes.

24.6 Chapter 24

Wireless TechnologyMost hams have an interest in gadgets.

In recent years, the publics use of radiowaves to communicate on the telephoneand via mobile computer networks hasincreased tremendously. This section ofthe chapter is written by Ron Milione,KB2UAN, and explains how these wire-less systems work. Reed E. Fisher,W2CQH, also contributed to the cellularsubsection.

Radio communications have been with usfor a long time, with analog voice as theprincipal application. Today, tens of mil-lions of people in the United States are usingtwo-way radio for point-to-point or point-to-multipoint voice communications.

The past 25 years have seen an explo-sion in wireless communications and com-puter technology. The past eight yearshave seen the explosion of the Internet.Standing at the center of this convergenceis wireless data technology.

Wireless data gives you the freedom towork from almost anywhere and gives youaccess to personal information when youare on the go. Whether the wireless sys-tem is accessing e-mail from an airport orreceiving dispatch instructions in a taxi,maintaining a data connection with a re-mote network from almost anywhere canbe realized.

Wire or fiber-based data communicationsspan a wide range of throughput and dis-tances56 kbps over a modem connection;10/100 Mbps over an Ethernet segment; andgigabit speeds over fiber. Similarly, wire-less connections span a wide range. Theworld of wireless data includes fixed micro-wave links, wireless Local Area Networks(LANs), data over cellular networks, wire-less Wide Area Networks (WANs), satellitelinks, digital dispatch networks, one-wayand two-way paging networks, diffuse infra-red, laser-based communications, keylesscar entry, the Global Positioning System(GPS) and more.

The benefits of wireless include com-munications when and where no othercommunication links are possible, con-nections at lower cost in many scenarios,faster connections, backups to landlines,networks that are much faster to install anddata connections for mobile users.

FUNDAMENTAL CONCEPTS INCELLULAR TECHNOLOGY

In a cellular radiotelephone system thedesired radio coverage area is divided upinto a number of smaller geographical ar-eas called cells. Fig 24.3 shows a typicalseven-cell (n = 7) cluster. Each cell has aradius r, which may be up to eight miles in

Fig 24.3 A seven-cell cluster.

Fig 24.4 Frequency reuse over an area to conserve spectrum.

Web, Wi-Fi, Wireless and PC Technology 24.7

a startup system. Each cell uses a uniquegroup of radio channels (channel set) thatis different from the others. Thus, there isno interference between radio users withina cell cluster. At the center of each cell islocated a base station (cell-site) with asso-ciated radio tower and antenna system.Mobile stations, located within the cell,communicate with the base station via two-way UHF radio links. The base stations arelinked to an MTSO (Mobile TelephoneSwitching Office) by landline (usuallywireline) transmission lines. The MTSO isconnected to the PSTN (Public SwitchedTelephone Network) by additional links.Thus, radio mobile station users can com-municate with wireline PSTN users.

Mobile station users can also communi-cate with other mobile station users, but onlythrough the MTSO and PSTN. The MTSOhas other important functions including lo-cation and handoff (handover). When alarger serving area is required, cell clustersare placed together as shown in Fig 24.4. Inthis configuration, all cells with the samenumber use the same channel set. This con-dition is called frequency reuse, a primefeature of cellular systems. Co-channel in-terference now becomes important, for amobile station in cell #1 may interfere withother mobile stations in the surrounding #1cells. In Fig 24.4, the distance betweensame-numbered cells is called D. The co-channel interference ratio is a function ofD/r. In a hexagonal grid D/r = n3 . For n =

both transmitter and receiver are active atthe same time. The transmitter of the basestation transmits on a forward (downlink)channel, while at the same time the trans-mitter of the mobile station transmits on areverse (uplink) channel 45 MHz lower.The cellular uplink band is 824-849 MHzand the downlink band is 869-894 MHz.The bands are divided into two blocks forthe two cellular service providers licensedin each coverage area. In 1995, the FCCallocated a new band for a new all-digital,cellular-like service called PCS (PersonalCommunications Service). The PCS up-link band is 1850-1910 MHz, and thedownlink band is 1930-1990 MHz. PCSalso uses FDD and the duplex frequencyspacing is 80 MHz. The bands are dividedinto six blocks for the six PCS serviceproviders licensed in each coverage area.There are currently more than 100 millioncellular and PCS subscribers in the UnitedStates (US).Cellular Air Interfaces

Air interfaces are the protocol standardsused by phone companies to provide cel-lular voice and data service. The base sta-tion, mobile station and MTSO hardwareand software are usually implementedwith proprietary equipment procured frommanufacturers chosen by the cellular/PCSservice providers. In contrast, the cellularair interfaces are documented in open(public) standards complying with FCCregulations.

Cellular/PCS standards in the US are gen-erated by the TIA and T1P1, then finallyapproved by the American National Stan-dards Institute (ANSI). Four standards pro-vide most of the cellular service in the US.Three of the four standards operate in the850-MHz cellular band. Three differentstandards operate in the 1.9-GHz PCS band.An obvious disadvantage of multiple air in-terface standards, and two frequency bands,is the difficulty encountered by roamingmobile stations when they enter non-homesystems. This problem has necessitated thedesign of higher cost dual-band, multi-mode mobile stations. The four standardsare:

AMPS (Advanced Mobile Phone Ser-vice) AMPS was the first cellular sys-tem in the US. Service commenced inOctober 1983 in Chicago. AMPS was stan-dardized by the TIA as IS-553. AMPS isan FDMA (Frequency Division MultipleAccess) system that means that user chan-nels are separated by frequency. (AmateurRadio currently uses FDMA.) The chan-nel spacing is 30 kHz, which allows 832FDD channels in each 25-MHz band near850 MHz. AMPS, is an analog/digital sys-tem. Voice uses analog PM (Phase Modu-

Fig 24.5 Cell size corresponding to density of population and use.

7, D/r = 21 = 4.58. For ground-to-groundUHF radio propagation, the received carrierpower (C) falls off with distance raised tothe 4th power. The worst case C/I (carrier-to-interference ratio) is: C/I = 40 log (D/r).For n = 7, C/I = 40 log 4.58 = 26.4 dB. Aproperly designed AMPS cellular systemrequires C/I > 18 dB in 95% of the coveragearea and this value provides satisfactoryvoice transmission.

As the mobile station moves away fromits serving base station, the mobile stationsreceived carrier power (C) becomessmaller and eventually approaches the sys-tem noise floor (N). The cell radius r mustbe kept small enough to provide a satisfac-tory carrier-to-noise ratio (C/N). An AMPSsystem with r = 8 miles, serving mobilestations with roof-mounted antennas, isdesigned to provide C/N > 18 dB in 95% ofthe coverage area.

Fig 24.5 shows the concept of cell split-ting, which is another feature of cellularsystems. For example, in densely popu-lated regions such as the center of a city,the cell radius can be reduced from eightmiles to four miles. Since the C/I is a func-tion of D/r, it is not reduced when D and rare both made small.

Cellular and PCS Frequency BandsThe 850 MHz cellular frequency band

was allocated by the FCC in 1974. Cellu-lar radios operate in the FDD (FrequencyDivision Duplex) mode that means that

24.8 Chapter 24

lation) with a peak frequency deviation of12 kHz. Digital system control, e.g. callsetup and handoff, uses 10 kbit/s binaryFM (Frequency Modulation) with a peakfrequency deviation of 7 kHz. There isno digital service provided to the users. Auser-provided modem must be attached tothe mobile station. At this time, most UScellular customers still use AMPS. (SeeRef. 1 at the end of this chapter for a de-scription of a typical AMPS base station.)By 1986, there was already worry thatAMPS service might soon become satu-rated in city centers. There was a competi-tive effort to design new cellular airinterfaces with increased spectral effi-ciency more user channels per MHz. Itwas decided that all future cellular sys-tems must be digital.

There are many advantages to digitaltransmission above the obvious benefit tousers requiring data transmission services.Unfortunately, there are a few disadvan-tages. Digital has a sharp threshold, sothere are no fringe coverage areas. Thereceived signal is either excellent, orabsent. Digital requires the use of low-bit-rate voice coders and their associatedartifacts. Wireline digital transmissionsystems encode voice using 64 kbit/s PCM(Pulse Code Modulation) waveformcoders that provide nearly distortion-freecoding. Since 64 kbit/s PCM cannot fitinto the narrowband radio channels, anumber of low rate, e.g. 8 kbit/s, codershave been devised. Most use the CELPprinciple that emulates a single humanvoice tract. Strange sounds may appear atthe receiver when the CELP coder is drivenby multiple voices, music or backgroundnoises. See Ref. 3 at the end of this chapterfor a description of CELP and other voicecoders.

TDMA (Time Division Multiple Access) TDMA was the first all-digital US cel-lular system. TDMA service started in thelate 1980s. It was standardized by the TIAas IS-54 and provided three times the traf-fic capacity of an AMPS system. It wasdesigned to gradually replace AMPS. Thechannel spacing was kept at 30 kHz so thatTDMA channels could be mixed withAMPS channels. Within each 30 kHz fre-quency channel are placed three time-di-vided digital channels. Thus, TDMA isactually a hybrid TDMA/FDMA system.QPSK (Quadrature Phase Shift Keying)modulation is used which provides a rawchannel bit rate of 48.6 kbit/s. The rawuser bit rate is 48.3/3 = 16.1 kbit/s. Afterbit error control techniques are applied,each user is provided an almost error free8 kbit/s data service or 8 kbit/s VSELP (aversion of CELP) voice coder service. Anupbanded version of TDMA, with en-

hanced features, operates in the 1.9 GHzPCS band. It is standardized as IS-136.

CDMA (Code Division Multiple Access) By 1986, some in the cellular industrybelieved that CDMA techniques would pro-vide more capacity than TDMA. In the US,CDMA was standardized by the TIA asIS-95. CDMA uses the same up and downbands as AMPS and TDMA, but channelspacing is 1.25 MHz. CDMA separates theuser bit streams by digital codes.

More than 40 users can occupy the same1.25 MHz frequency channel at the sametime. The raw bit rate provided to eachuser is 28.8 kbit/s. After bit error control,each user is given a 9.6 kbit/s data channelor 13 kbit/s QCELP (a version of CELP)voice service. In this direct-sequence typeof CDMA transmitter, the incoming user-generated bit stream (either digital voiceor data) is multiplied (exclusive-OR) witha 1.2288 Mbit/s pseudo-random digitalspreading code. Each user is given a uniquecode. The 1.2288 Mbit/s multiplier outputbit stream enters a QPSK modulator, and isthen amplified and transmitted with aspreaded RF bandwidth near 1.25 MHz.

In the CDMA receiver, the incomingmixed signal received from all of theactive usersis multiplied by the desiredusers unique code that is synchronizedwith the transmitter code (a challengingtask). Only the desired users de-spreaded28.8 kbit/s bit stream will emerge from themultiplier. The other codes emerge aswideband noise that is eliminated by alow-pass filter.

Tight mobile-station, transmit-powercontrol must be used for the CDMA systemuplink to achieve its expected capacity. Allmobile station transmissions received at thebase station should be within a few dB ofeach other. To achieve this severe require-ment, mobile station power output is up-dated 800 times per second by a basestation-generated 800 bit/s power controldata stream interspersed into the downlink28.8 kbit/s data stream.

It is difficult to calculate the user capac-ity of a CDMA system. The per-channelspectral efficiency of CDMA (40 bitstreams in 1.25 MHz) is comparable withAMPS (40 channels in 1.20 MHz). How-ever, CDMA is so resistant to co-channelinterference that all CDMA radio chan-nels can be used in all cells (n = 1). There-fore, there is a traffic capacity increase ofat least seven times that of a standardAMPS system. An upbanded version ofCDMA, with enhanced features, operatesin the 1.9-GHz PCS band. It is standard-ized as IS-95A.

GSM/PCS-1900 GSM (Global Sys-tem for Mobile Communications) was im-ported from Europe in the mid 1990s. In the

US it operates only in the 1.9 GHz US PCSband. It was standardized by the T1P1 asJ-STD-007. It is a TDMA/FDMA system.Frequency channel spacing is 200 kHz andthe channel bit rate is 270 kbit/s. GMSK(Gaussian Mean Shift Keying), a type ofnarrowband binary FM, is the modulationmethod. There are eight time slots in eachRF channel, so the user raw bit rate is 270/8= 33.75 kbit/s. After bit error control, eachuser is provided a 9.6 kbit/s data channelor a 13 kbit/s RPE-LTP (Regular PulseExcited-Long Term Prediction) voice coderfor voice. The spectral efficiency of GSM(8 bit streams in 200 kHz) is only slightlybetter than AMPS (8 channels in 240 kHz).This weakness is mitigated by using n = 4,a layout tolerated by the more interference-resistant GSM digital transmission. Thus,GSM can handle about twice as much trafficcapacity as AMPS.

Radio Link Operating ProtocolsThe AMPS system uses three protocols

for system communication between thebase station and the mobile station:

PAGING At least one channel in eachcell is used for paging mobiles with incom-ing calls from the MTSO. A downlink pag-ing bit stream, the same in each cell, iscontinuously monitored by power-ON, non-active mobile stations. When a mobile sta-tion recognizes its user number, it respondson the uplink-paging channel. The pagingstream then hands off the mobile station to asetup channel. Conversely, the mobile sta-tion originates a call by sending its requeston the uplink-paging channel.

SETUP At least three channels areused in each cell for setup; the mobile sta-tion-base station link sets up and tears downcalls. After the two-way setup procedure isfinished, the mobile station is commandedto tune to its assigned voice channel. Mobileauthentication is performed during setup.Each mobile station has a NAM (NumericAddress Module) and an ESN (ElectronicSerial Number). The NAM contains theusers telephone number. The manufacturer-assigned ESN is unique. At setup, the MTSOverifies that the NAM and ESN numbers arevalid.

LOCATION AND HANDOFF Whilean active mobile station is linked to its serv-ing base station, its radio signal strength isalso being periodically monitored by the sixsurrounding base stations. When the aver-aged signal strength at a neighboring basestation exceeds that measured at the servingstation, the MTSO commands a handoff tothe neighbor. This handoff procedure allowsun-interrupted trans-mission as the mobilestation moves through the cell cluster.Handoff is accomplished by a blank-and-burst procedure. The down-link voice

Web, Wi-Fi, Wireless and PC Technology 24.9

channel is interrupted, and a brief 10 kbit/sdigital message commands the mobile tomove to its newly assigned frequency chan-nel. The mobile station acknowledges, viablank-and-burst on the uplink voice chan-nel, then tunes to the newly assigned chan-nel. If handoff fails, the call is terminated.

The TDMA, CDMA and GSM digitalsystems use similar procedures. DSP(digital signal processing) techniques pro-vide better authentication and user pri-vacy. Details are found in Ref. 2 at the endof this section.

Virtual Private NetworkA Virtual Private Network is created

when a mobile user connects a data termi-nal to a foreign network, either via dial-inor public networks, and establishes a pres-ence equivalent to a direct connection tothe home network.

The Wireless Mobile IP solution is in-tended to enable the creation of VirtualPrivate Networks by using the Internet asthe communications backbone to connectmobile users. The following features char-acterize Virtual Private Networks:

Remote presence the ability to estab-lish remote network connections and stillappear to be connected to the home net-work.

Network independence the ability toroam among networks (e.g., BellSouthWireless Data Network, CDPD, WirelessLAN, Ethernet). Traditionally, IP networkindependence (roaming) is done over thesame media access (e.g., SLIP, PPP,Ethernet). Virtual Private Network imple-mentation offers the ability to roam acrossnot only single media IP networks, butacross multiple wireless and wireline me-dia without user intervention.

Security the ability to help createsecure channels for authentication, dataintegrity, and data privacy.

Third Party Mobile IP this solutionis unique in that it provides wireless andwireline IP network and media roaming/communications to both Intranet andInternet services.

The ability for mobile users to roamseamlessly and without interventionamong radio frequency (RF) networks andwireline networks allows the system tooperate at maximum system efficiency.

MOBILE COMPUTINGWith the rapid growth and availability of

wireless data networks, wireless communi-cations tools and Internet standards, mobileworkers are finding new ways to do businessin todays competitive environment. Theneed for the mobile worker to access mis-sion-critical information requires access tocorporate databases and Internet/Intranet

applications. In addition, convenient andreliable file transfer, integrated messaging,and personalized information delivery allowthe mobile employee to work at peak pro-ductivity levels.

Successful communications betweenmobile workers and their corporate envi-ronment requires the right combination oftechnologies. From a business standpoint,these technologies must be cost-effectiveand easy to use. For long-term viability,they should be based on open system archi-tectures and industry standard interfaces.

Virtual Private Networks have emergedto provide networking solutions to a grow-ing mobile workforce. These networksallow businesses to provide their mobileemployees with access to corporate infor-mation and applications by connectingthem to the enterprise via the Internet. AVirtual Private Network provides a lowcost extension to the enterprise while of-fering secure access to an open network-ing environment.

Mobile IP SecurityMobile IP is an Internet industry standard

that enhances the IP protocol to remedythese existing problems and allow the trans-parent routing of IP datagrams to mobilenodes on the Internet. Security is an integralpart of building a Virtual Private Networksolution. The Wireless Mobile IP NetworkConfiguration utilizes Mobile IP encryptionto form a secure channel between the Wire-less client and server to support user authen-tication, data integrity, and data privacy inmobile environments.

Using the Wireless Mobile IP encryp-tion, a secure channel is formed whichallows various foreign networks to be-come extensions of the home network.

Mobile IP BenefitsThe Wireless Mobile IP solution is in-

tended to enable enterprises to create theirown Virtual Private Networks, thus pro-viding:

(1) Low initial costs(2) Low operating costs(3) Solution flexibility(4) Significant productivity gainsBy providing seamless network roam-

ing and communications capabilities,Mobile IP provides a networking solutionto bring enterprises into the 21st century.

Many of the spread spectrum deviceson the market today are listed as FCCPart 15 devices. There are three frequen-cy bands allocated to this service:

902-928 MHz (26-MHz bandwidth)2400-2483.5 MHz (83.5-MHz band-

width)5725-5850 MHz (125-MHz bandwidth)

RegulationsIn 1999, the FCC greatly liberalized ama-

teur spread spectrum rules, allowing spread-ing techniques not previously permitted.Amateurs are no longer limited to frequencyhopping and direct sequence; any docu-mented spreading code may now be utilized.Amateurs may now freely use SS devicesdesigned under Part 15 of the Commissionsrules for amateur applications as well, keep-ing in mind the identification requirementsof the Amateur Service. The maximumpower allowed for an amateur SS emissionis now 100 watts, up from the previous limitof a single watt! However, stations thattransmit more than one watt must utilizeautomatic power control to limit power out-put to the minimum necessary to communi-cate. For information on the rules change,see ARRLWeb at: www.arrl.org/news/stories/1999/09/08/2/. For the text of therules, see Section 97.311 in The ARRLFCC Rule Book.

KEEPING CURRENT WITHWIRELESS

Changes to the wireless communicationsindustry have been dramatic since the firstmobile phone systems were introduced. Thehigh-tech, expanding nature of this fascinat-ing area will continue to drive new wirelesscommunication developments. The follow-ing are some related Web sites where inter-ested readers can keep up-to-date on thisfast-paced technology:Cellular Communications and Internet As-

sociation (CTIA): www.wow-com.com/Protocols.com Reference page:

www.protocols.com/pbook/cellular.htm

FCC Cellular Services:wireless.fcc.gov/services/cellular/

International Engineering Consortium:www.iec.org/online/tutorials/cell_comm/

Wireless Application Protocol (WAP):www.cellular.co.za/wap.htm

Waveguide, A brief history of Cellular:www.wave-guide.org/archives/waveguide_3/cellular-history.html

Mobile Cellular Technology Newsletter:www.mobilecomms-technology.com/

An overview of cellular technologies:www.ee.washington.edu/class/498/sp98/final/marsha/final.html

References1. Advanced Mobile Phone Service,

The Bell System Technical Journal, Vol 58,No. 1, Jan. 1979.

2. V.K. Garg and J.E. Wilkes, Wirelessand Personal Communications Systems,Prentice Hall, 1996, ISBN 0-13-234626-5.

3. J. Bellamy, Digital Telephony, JohnWiley, 1991. ISBN 0-471-62056-4.

24.10 Chapter 24

PC Technology (Personal Computers in the Shack)The Personal Computer debuted in 1980

with offerings by Commodore (PET),Tandy (TRS-80) and Apple (Apple II).Almost immediately, hams found them tobe useful additions to the shack. These firstcomputers were little more than a 4-MHzprocessor with a little RAM (4kB) an audiotape drive and an imbedded BASIC operat-ing system. One of the first applicationsavailable for hams was an RTTY decoder.The age of digital modes for hams wasabout to expand exponentially.

As the photo in Fig 24.6 indicates, todaythe PC is an important part of any radio sta-tion. In most cases, it is the control center ofthe various pieces of equipment we use. Inan extreme example, you can use it to down-load from the web the test questions to takeyour exam, learn the code, design yourantennas, and even search ebay or QRZ.comto buy a radio. It can control the radio, pro-vide various digital modes through the useof the sound card, connect to the Internet forsolar flux numbers to compute which bandshave propagation, use TELNET for packetspots to help find a DX station, provide soft-ware to log the QSO and keep track of awardprogress, and finally assist the operator infinding the QSL route to complete the pro-cess (or in the case of the new Logbook ofThe World (LoTW) upload the QSO to theARRL site and perhaps have that confirma-tion in hours). What could be a more impor-tant tool to the operator?

ERGONOMICSSince the computer will connect to most

of your equipment, it is usually found in thecenter of the operating arena. A tower uniton the floor will give it some distance fromthe RF generators and keep the desktop freefor equipment that you need to handle. A

well-designed station will have the key-board, mouse and keyer (assuming you area CW op!) all within a 45-degree arc oneither side of your operating chair. Use ofan LCD monitor will preserve more spaceon your desk as well as produce less RF inthe shack.

HARDWAREThe computer itself should have a

minimum of 256 MB of memory (more isbetter), hard drive with 40 GB minimumspace, a rewritable CD, two serial ports,and a sound card. Serial ports are becom-ing a thing of the past; newer PCs havereplaced them with USB ports. However,there are now many commercial USB-to-Serial Converter devices that allow you tostill connect older DB9-serial devices tothe newer PCs. If you are connecting yourstation to the Internet (recommended), youalso need to consider a modem or Ethernetport depending on your Internet serviceprovider. To save space on the operatingtable, locate your PC on the floor if pos-sible (tower) and use an LCD display topreserve maximum desk space and beless of a heat source.

One of the first things to consider isinterference from the radio to the PC orfrom the PC to the radio. If your radio isproperly grounded, your antennas at aproper distance from the shack, and youuse well-shielded cables, the chance of RFgetting into your PC is remote. It is alsogood practice to try to keep your radiosand computer equipment on separatepower circuits.

Receiving computer-generated RF inyour radios is often the result of poorlydesigned monitors or leakage from themonitor cables. Whenever adding new

computer equipment into the shack it isgood to immediately scan the bands to findany new birdies or new noise. Should therebe any, shutting off the monitor and thenthe computer will isolate which of the twopieces of equipment are at fault. In manycases, the installation of toroids on themonitor cable and all cables (power,speaker, CAT, Keyboard or Microphone)that are a source of radiating will elimi-nate the problem.

Most modern radios have a CAT (Com-puter Access Terminal) port that is a serial9 pin (MINIDIN9). Some older radios re-quired a computer interface device thatwas usually RS232 based. Yet other radiosuse DIN6 or CI-V interface devices. Com-plicating the interface issue is the trend toUSB ports instead of serial ports. Fortu-nately, the commercial ham market haskept up with the lack of standards with ahost of good USB to Radio Port products.MicroHam is one such source (www.microham.com) covering just about allthe USB wiring possibilities. The basiccommands to control your radio are avail-able from the radio manufacturers Websites. Third-party software applications allsupport these functions and are discussedin detail below.

Your computer sound card can act as adigital modem enabling you to operateFSK, PSK, SSTV, FAX and other digitalmodes. However, you also will find theneed for a direct-controlled interface tokey the transmitter in response to signalsover the serial ports RTS or DTRpins. The interface should also include anattenuator to simplify the connection be-tween the computer sound card and thetransceiver microphone jack. This type ofinterface may also be used to connect your

Fig 24.6 Don, N1DG, and his computer-enriched operatingstation. Fig 24.7 The DXLAB Commander Control Panel.

Web, Wi-Fi, Wireless and PC Technology 24.11

computer to your radio for Echolink orIRLP operation. The RIGblaster fromWest Mountain Radio is one of severalcommercial products for this.

Lastly, most logging and contest soft-ware generates Morse code. Connectingthe output of the radio to the input of thesound card is simple enough with a stereocable. However, be sure to isolate the twodevices with an isolation transformer inthe cable (such as a RadioShack 273-1374) to prevent 60-Hz hum from arrivingwith the signal. The output from the PC tothe radio can come either from a parallelor serial port. There are several commer-cial products available, the best for paral-lel ports being from Jack Shuster,W1WEF. Two suppliers of interfacesare N3JT (n3jt@arrl.net) and W1WEF(w1wef@arrl.net).

The recent introduction of Windows XPfurther complicates the software output toserial or parallel ports. WinXP no longerallows programs direct access to them.However, there are two shareware pro-grams Directio and Userport that willinstall drivers on your operating system toallow most ham logging and modem soft-ware to reach the ports. Both are free down-loads at www.embeddedtronics.com/design&ideas.html.

SOFTWARERadio Control Software

One of the most popular free pro-grams is Commander, (www.qsl.net/civ_commander/) by DXLab Software. Itis one of many shareware modules byDXLabs and this specific program inter-faces with the recent radios from Ten-Tec,ICOM, Kenwood and Yaesu.

Through its graphical interface shownin Fig 24.7, a click of the mouse allowsyou to set filters, frequency ranges pursu-ant to your license class, memories forfavorite frequencies and customization forthe way you want your radio setups. Allthe logging programs listed below haverig control as part of their logging features.However, most of the general logging pro-grams do not have the ability to set filtersand menu items as Commander does (seeFig 24.7). They are designed for otherthings.

Logging SoftwareIn 1986, two logging programs ap-

peared for MS-DOS-based PCs thatwould inaugurate an easier way of keep-ing track of operating awards and con-testing scoring. The first, the WB2DNDLog Database, was built around DBASEIII and became popular among DXers andDXpeditioners. At the same time, K1EA

introduced CT. Computerized loggingenabled faster contacts, more accuraterecording of those contacts, easy scoringand simple QSL management. Todayslogging software not only logs, but it con-trols the radios, uses the sound card tosend and decode digital mode transmis-sions, and even interfaces to packet-spot-ting networks via VHF packet or Internetnodes.

In 1996, the CEZ and VKHI expedi-tions took computer logging to the nextlevel by posting their logs on their Websites during the DXpeditions so hamscould check their progress while theDXpeditions were still in progress. Inorder to standardize the format amongthe many logging programs that appearedover the last 15 years, two standardsemerged to allow for the easy use of theinformation being collected. Generallogging programs now allow you to ex-port your data in a format known as ADIF(Amateur Data Interface Format), whichallows you to use multiple programs andmove data among them and share log datawith friends or QSL Managers. You neverneed to worry about obsolescence of yourdata. If your publisher goes out of busi-ness, or no longer supports new platforms,you can choose from a large selection ofother programs that will load your logswithout retyping everything.

The second format has been written andis used by contesters to submit their scoresto the various organizations sponsoringthe contests. This format is known asCabrillo and is available on all contestsoftware today. By submitting all contestlogs in a standard format, adjudicators canlink the logs with a common database andquickly see errors for scoring adjustments.

It is worth noting that both current gen-eral logging programs and contest soft-ware also handle both of these standardsto make transferring the contest logs intothe general logging programs for awardtracking.

LoTWNo discussion of general logging and

the award tracking can be complete with-out a discussion of the latest developmentin this area. In 2003, the ARRL launcheda web-based depository of QSO datacalled the Logbook of The World (LoTW).The purpose is to electronically verifyQSLs and provide those certified QSLsfor its award programs (and eventuallyother ham-organization award pro-grams). LoTW has its own website (www.arrl.org/lotw/default) that is passwordprotected. Membership is free but digitalcertificates and passwords are issuedonly after licensing, and user details are

verified by mail to the address of the lic-ensee. This assures that the data submit-ted is actually done so by the operator.

The free software to obtain your cer-tificate (called TQSL), and instructions,are downloadable from www.arrl.org/lotw/#download. Once receiving a digi-tal certificate, the Cabrillo or ADIF logscan be signed and uploaded over the webto the database. The software automati-cally matches your data to the databaseand shows your QSLs in a variety of for-mats. In the first six months since the website went live, 7,000 users have uploadedover 40 million QSO records resulting inQSL matches of over 1.2 million records.

Logging/Contesting SoftwareSome of todays popular logging/con-

testing software packages include:

CT (ConTest, by K1EA) Web site:k1ea.com

Contest logger for DOS/Win85/98/2000Freeware

Dxbase (by Scientific Solutions). Website: dxbase.com/proddxbw.htm

General logging software for Win95/98and Windows/NT/2000 $90

DX4WIN (by KK4HD). Web site:dx4win.com/

General logging software for Win95/98/ME/XP/2000/NT $99.

EasyLog (by Microware Software). Website: easylog.com/eng/index.htm

Windows full-featured logging software$89.54.

HC Log (Buckmaster Publishing). Website: http://hamcall.net

Logging software integrated to workwith HamCall CD-ROM.

Logic 7 (Personal Database Applica-tions, Inc.). Web site: hosenose.com

Windows full-featured logging software$129.

MiLOG (SA Engineering). Web site:logwindow.com

Contesting software for Windows$69.95.

NA (by K8CC). Web site:datomonline.com

Contest logger for DOS $60.N1MM Logger (by N1MM, AB5K,

PA3CEF, G4UJS, N7ZFI, N2AMG).Web site: http://pages.cthome.net/

n1mm/Contest logger for 95/98/ME/NT/2000/

XP Freeware.N3FJP Software. Web site: n3fjp.comWindows-based logging/contesting

software. Various prices by contest/version.

24.12 Chapter 24

ProLog2K (by W5VP) Web site:prolog2k.com/

General logging software for Win95/98/ME/2000/NT/XP $50.

SWISSLOG (by HB9BJS) Web site:informatix.li/english/Frame_EN.htm

General logging software for Win95/98/ME/NT4/2000/XP 70 Euros.

TR Log (by N6TR) Web site: qth.com/tr/Contest logger for DOS $75.VHF log (by W3KM) Web site: http://

www.qsl.net/w3km/features.htmVHF contest logger With CW/PTT/DVK

for Win98, ME, 2000 or XP.Freeware.

WinEQF (by N3EQF) Web site: eqf-software.com

General logging Program for Win95/98,ME, NT, XP, or Win2K $59.95.

WriteLog (by W5XD) Web site:writelog.com/

Contest logging software for Win95/98,NT, Win2K $75.This list is by no means complete but it

will give you a start to explore the prod-ucts available based on your interests.

PACKETCLUSTER AND ARCLUSTER

During the late 1980s, Dick Newell,AK1A, developed PacketCluster softwareto link PCs together via VHF radios to DX-related information. Now 15 years later,the software is still in use, but is slowlybeing replaced by Internet-based Telnetsoftware such as AR Cluster, DX Spider,CLX, DxNet, Clusse, and WinCluster.

These software servers enable users toannounce and receive DX spots, generalinformation announcements, and sendpersonal talk messages and email. Almostall logging software today has Telnet soft-ware built in to interface to the Internetnodes and retrieve Cluster spots.

AR Cluster (developed by AB5K) al-lows the user to tailor the information hereceives. Since it is an SQL Database, the

user can query that database in an almostunlimited way. SH/DX commands can beby call, band, mode, DX Country, State orCountry of the spotter, the node the spotcame from, DTS (Date/Time stamp), ITUor CQ Zone, or even from a comment as-sociated with the spot. Further, the inquirycan be any one or all of the above param-eters. Looking for the last 50 spots for aDXpedition is as simple as sh/dx/50CALLSIGN. The user can also set specificfilters for his use so that spots sent to himare set to the specific parameters he has setfor his call. A VHF-only user does not needto see HF spots. Spots outside of licensedfrequencies can be ignored, etc. The AR-Cluster user manual can be read atwww.ab5k.net/ArcDocs/UserManual/ArcUserManual.htm.

One of the best sources of Telnet Hamradio sites is maintained by K6PBT on hiswebsite http://telnet.dxcluster.info/.

MODE-SPECIFIC SOFTWAREThe ability of using the sound card as a

modem has enabled hams to operate manydigital modes without addition equipment.Software has emerged that generate anddecode these modes and in some caseseven log the contacts made. While someof the logging software listed earlier in-cludes mode decoding routines, the mostfeature-rich software is mode specific.Some popular programs in this softwarecategory:

Multi-Modes:RadioCom 5 (by Computer Interna-

tional, Bonito line). Web site:computer-init.com

Skysweep (Skysweep Technologies).Web site: skysweep.com.

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Introduction to the CD-ROM EditionUsing this CD-ROMFull-Text SearchingARRL on the Internet

Front MaterialCover I (Front)Cover IITable of ContentsForewordAmateurs CodeSchematic SymbolsThe ARRLAt Your Service

Chapter 1What is Amateur (Ham) Radio?Hobby of DiversitiesYour LicenseUS Amateur BandsHam Radio ActionGetting StartedGoverning RegulationsResourcesGlossary

Chapter 2Activities in Amateur RadioAwardsContestsNetsAmateur Radio EducationEmergency CommunicationsSpecialized Communications

Chapter 3SafetyAntenna and Tower SafetyPower LinesElectrical Wiring around the ShackLightning/Transient ProtectionGroundsProject: An Earth-Continuity TesterStation PowerFCC RF-Exposure RegulationsSafe HomebrewingRF Radiation and EMF SafetyOther Hazards in the Ham Shack

Chapter 4Electrical FundamentalsDC Circuits and ResistanceSeries and Parallel ResistancesPower and EnergyCircuits and ComponentsAC Theory and ReactanceFrequency and PeriodCapacitance and CapacitorsInductance and InductorsQuality Factor (Q) of ComponentsCalculating Practical InductorsOhms Law for ReactanceImpedanceResonant CircuitsTransformers

Chapter 5Electrical Signals and ComponentsAnalog GlossaryAnalog Signal ProcessingAnalog DevicesPractical SemiconductorsTransistor Amplifier DesignDigital FundamentalsNumber SystemsPhysical Representation of Binary StatesCombinational LogicSequential LogicDigital Integrated CircuitsComputer Hardware

Chapter 6Real-World Component CharacteristicsLumped vs Distributed ElementsLow-Frequency Component ModelsComponents at RFThermal ConsiderationsThe Thermistor in Homebrew ProjectsLow-Frequency Transistor Models

Chapter 7Component Data and ReferencesComponent ValuesComponent MarkingsInductors and Core MaterialsOther Sources of Component DataSemiconductorsIntegrated CircuitsVacuum TubesOtherReferencesGeneral/Electronics/ComputersComponents/EquipmentAntennas/Transmission LinesModesOperating and InterferenceMessage Handling

Chapter 8Circuit ConstructionShop SafetyTools and their UsesProject: A Deluxe Soldering StationProject: Soldering-Iron Temperature ControlElectronic CircuitsSurface Mount Construction TechniquesFrom Schematic to Working CircuitMicrowave Construction TechniquesHigh-Voltage TechniquesMechanical Fabrication

Chapter 9Modes and Modulation SourcesIssues Common to all Transmission ModesEmission ClassificationsEmission Modulation and Transmission CharacteristicsMajor Modulation SystemsInternetworkingRadio Control (R/C)Voice ModesImage ModesSpread SpectrumMultimedia Systems

Chapter 10Oscillators and SynthesizersHow Oscillators WorkPhase NoiseOscillator Circuits and ConstructionVHF and UHF OscillatorsFrequency SynthesizersPhase-Locked LoopsSynthesizer in an MF/HF TransceiverTrends in Oscillator Applications

Chapter 11Mixers, Modulators and DemodulatorsThe Mechanism of Mixers and MixingPractical Building BlocksTesting and Calculating IMD in Receivers

Chapter 12RF and AF FiltersBasic ConceptsFilter SynthesisDesigns using Software/SVC TablesChebyshev Filter DesignQuartz Crystal FiltersMonolithic Crystal FiltersSAW FiltersTransmission-Line FiltersHelical ResonatorsActive FiltersProject: Crystal Filter EvaluationProject: Band-Pass Filters for 144 or 222 MHzProject: High-Performance Passive CW FilterProject: Broadcast Band Rejection FilterProject: A Wave Trap for Broadcast StationsProject: Second-Harmonic-Optimized LP FiltersProject: The Diplexer Filter

Chapter 13EMI/Direction FindingThe Scope of the ProblemResponsibilityEMC FundamentalsCuresTVI Troubleshooting ChartAmateur Harmonics/CATV ChartProject: Finding Shack Noise SourcesRadio Direction FindingProject: The Simple SeekerProject: Active Attenuator for VHF-FM

Chapter 14Receivers and TransmittersA Single-Stage Building BlockNegative Feedback in RF DesignReceiver Design TechniquesThe Superheterodyne ReceiverVHF and UHF ReceiversProject: GaAsFET Preamp for 430 MHzProject: Microwave Receiver for 10 GHzTransmitter DesignProject: A Rock-Bending Receiver for 7 MHzProject: A Wideband MMIC PreampProject: A Binaural I-Q ReceiverProject: A Superregenerative Receiver with SquelchProject: A Broadband HF Amp using MOSFETSProject: A Drift-Free VFOProject: A Simple Regenerative HF Receiver

Chapter 15Transceivers, Transverters and RepeatersTransceiver ExampleProject: The Norcal SierraAn 80-15 M CW TransceiProject: A 10-Watt SSB Transceiver for 60-M BandTransvertersRepeaters

Chapter 16DSP and Software Radio DesignDSP FundamentalsDSP Algorithms for RadioAnalytic Signals and ModulationDigital Speech ProcessingInterference-Reduction TechniquesFourier TransformsRadio Architectures for DSPSoftware RadiosHardware for Embedded DSP SystemsDSP System SoftwareDSP ProjectsProject A: DecimationProject B: FIR Filter Design VariationsProject C: Analytic Filter Pair GenerationProject D: Newtons Method for Square RootsProject E: A Fast Square-Root AlgorithmProject F: A High-Performance DDSProject G: Fast Binary Multiplier in High-Speed CMOS Logic

Chapter 17Power SuppliesGlossaryAlternating-Current PowerRectifier TypesRectifier CircuitsFiltrationRegulationHigh-Voltage TechniquesBatteries and ChargingEmergency OperationsPower-Supply ProjectsProject: Series-Regulated 4.5- to 25-V SupplyProject: 13.8-V, 40-A Switching SupplyProject: 28-V, High-Current SupplyProject: Commercial-Quality, High-Voltage SupplyProject: Micro M+ Charge ControllerProject: The UPSA Universal SupplyProject: A Portable Power Supply

Chapter 18RF Power AmplifiersTypes of Power AmplifiersDesign ExamplesProject: 3CX1500D7 RF Linear AmplifierProject: A 6-Meter kW AmplifierProject: A 144-MHz Amplifier

Chapter 19Station Layout and AccessoriesFixed StationsMobile and Portable InstallationsProject: Tick-2A Tiny CMOS Keyer 2Project: Vintage Radio T/R AdapterProject: Quick and Easy CW with your PCProject: An Expandable Headphone MixerProject: A Simple 10-Minute ID TimerProject: Audio Break-Out BoxProject: An SWR Detector Audio AdapterProject: PC Voltmeter and SWR BridgeProject: Tandem MatchAn Accurate Directional WattmeterProject: Automatic Antenna Switch for Yaesu or ICOMProject: A Trio of Transceiver/Computer InterfacesProject: Computer-Controlled Two-Radio SwitchboxProject: TR Time-Delay GeneratorProject: A Switched AttenuatorProject: Simple QRP TR ChangeoverProject: QRP L-Match ATUProject: QRP T-Match ATUProject: An Ugly Transformer for Heavy-Load Stations

Chapter 20Propagation of RF SignalsFundamentals of Radio WavesPropagation Summary by BandMUF PredictionPropagation in the TroposphereExtraterrestrial Propagation

Chapter 21Transmission LinesBasicsMatched LinesReflections on the Smith ChartMatching the Antenna to the LineMatching the Line to the TransmitterLoads and Balancing DevicesWaveguides

Chapter 22AntennasAntenna PolarizationDipoles and the Half-Wave AntennaProject: 135-FT Multiband DipoleAntenna Modeling by ComputerProject: A 40/15-M Dual-Band DipoleProject: K8SYL 75/10-M Dual-Band DipoleProject: W4RNL Inverted-U AntennaProject: Two W8NX Multiband, Coax-Trap DipolesVertical AntennasOptimum Ground Systems for Vertical AntennasProject: Dual-Band Verticals for 17/40M or 12/30MInverted L and Sloper AntennasProject: 1.8-MHz Inverted LProject: Half-Wave Vertical Dipole (HVD)Project: The Compact Vertical Dipole (CVD)Project: All Wire 30-M CVDYagi and Quad Directive AntennasQuad AntennasProject: Five-Band, Two-Element HF QuadProject: Simple Quad for 40 MProject: Simple Loop for 28 MHzHF Mobile AntennasVHF/UHF AntennasProject: Simple Portable Groundplane AntennaProject: Dual-Band Antenna for 146/446 MHzProject: A Quick Antenna for 223 MHzProject: An All-Copper 2-M J-PoleVHF/UHF YagisProject: 3- and 5-Element Yagis for 6 MProject: A Medium Gain 2-M Yagi

Chapter 23Space CommunicationsAn Amateur Satellite PrimerAmateur Satellite HistoryProject: Single Brick L-Band AmplifierProject: Double Brick L-Band AmplifierProject: Parabolic Dish ConstructionProject: Helix Feed for an Offset DishProject: Integrated AO-40 Antenna SystemGlossary of Satellite TerminologyEarth-Moon-Earth (EME)

Chapter 24Web, Wi-Fi, Wireless and PC TechnoloThe World Wide Web (www)The InternetHams Guide to Useful Internet SitesGlossary/Wireless Fidelity (Wi-Fi)Glossary of Wireless TechnologyWireless TechnologyPersonal Computers in the ShackMode-Specific Software

Chapter 25Test ProceduresTest and Measurement BasicsDC Instruments and CircuitsAC Instruments and CircuitsProject: The MicrowatterFrequency MeasurementProject: Marker Generator with Selectable OutputProject: A Dip Meter with Digital DisplayOther Instruments and MeasurementsProject: A Wide-Range Audio OscillatorProject: Measure Inductance and Capacitance with a DVMOscilloscopesProject: HF Adapter for Narrow Bandwidth ScopesProject: A Calibrated Noise SourceProject: Signal Generator for Receiver TestingProject: Hybrid Combiners for Signal GeneratorsProject: Compensated Modular RF VoltmeterReceiver Performance TestsTransmitter Performance Tests

Chapter 26Troubleshooting and RepairSafety FirstWhere to BeginTesting within a StageLook for the ObviousTypical Symptoms and FaultsTroubleshooting HintsAfter the RepairsProfessional Repairs

Back MaterialAdvertisingARRL Membership FormIndexAbout the ARRLCover IIICover IV

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