04 April 1998

Vol. 17, No.4 April 1998

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CONTENTS

Vol. 17, No.4 April 1998 (ReJ/nstalling the Oak Tree Antenna 11

A~Jl~U ~ll C" tllROtUY Ull f

By Arthur Lee. There used to be a say ingamon g hams that a tree wa s an integ ral part ofa d ipole ante nna. says the author. But what ifthat dipo le has been downed for a couple ofyears. the tree has grow n too high . and the guy

wires keep snap pi ng und er se vere wea the r'! Shortwave listeners will ap preciatethese simple so lutions born of ex perie nce!

By William Rhodes. Unlike the mult i-turn loops popular forthe ir directiona l properties. these tunable, single-turn. ha lf-wa ve loops have no null. Instead. the y provide consistent.noise- and fade-free liste ning.

By James Williams. Simplicity itself, this portable version of the time-honoredtransmitting or receiving antenna design is constructed of readily-availabletwinlcad,

By Richard Marris . If you are using a directi onal loop or ferrite antenna to zeroin on a signal by rotat ion. this ho rncbrcw turntable is a perfect companion to yo urmonitoring po st.

ByA.W. Edwards. Is yourtower under-utilized because it ' s too mu ch difficult orda ngerous to cl imb up and ins ta ll mou nting hardware '! Is there a tower ava ilab leat your DX camp? Wh ether yo u ante nna is wire or mast-mounted. this bracketsupport is so qui ck and easy yo u' ll wonder wh y you didn 't thin k of it first.

ByA. W. Edwa rd s. Learn how to construct two basic antenna tuner circui ts, plusan RF pro tection c ircuit.

~Il LJJrill!F ~~

~By Ha ns Johnson. You m il escape interference at home

-== and go on a DXpedi tion every da y. How'! By turning- 0 0 yo ur car into a go -anywhere mon itoring post!

Dual-Band VHF/UHF J-Pole 20

The Quickie, Snapon Tower Bracket 14

Two Varicap Tuned Receiving Loops 16:I" ~~. ~"'".... 1",,:~'

Dealing with Strong Signals 24

ASimple Turntable for Loops 18

Covel' Story

AM Transmitter Sites

Al1tetJ lIClS are the topic ofinterest in this issue. Some of thelargest antennas that dot ourcountryside belong to AM broad-cast stations. At these sites thetowe r doe s not suppo rt the antenna:The tower is the antenna. And youthought one tower was j ust thesame as another .... !

The aut hor introduces you toways to identify an AM radio towerand some of the technical co nsider-atio ns tha t go into engineering abroadcast site. AfT readers also gettrea ted to an inside look at theconstruction of KLTI's antennasite in Commerce City. Colorado.

Story starts on page 8. Coverphoto: A multiple-antenna arraynear Miami, Florida (show n onhorizon), photographed by RossCobb, Aerials. lne.http://www.aerialsinc.com

By Patrick Griffith

Postmaste r:Se nd a dd ress ch a nges to Mon itoring Times,P_O. Box 98, Brasstown. NC 28902-0098 .

Subsc ription Rctes: S23.95 in US; 536 .50Canoda; a nd 555..45 foreign elsewhere, usfunds. lobel ind ica tes lost issue of subscrip -tion.See page 95 Forsubscriptioninformation.

Copyrigh l 1998 . Per iodica ls postage paid0 1 Brasstown, Ne, a nd addit iona l mailingoffices . Short exce rpts moy be repr intedwith appropriat e credit. Complete arti clesma y not be re prod uced wi thou t permi ssion .

On the Ham Bonds ,..,. ,.,.,.,. .,.,.,. ,...,..,.. 70More Hom Software

And More! ,.,.,. ,.,.. ,.,. ,.,.,. .,.,.,. ,..,.,. ,...,.. 71Maxon SP-l DOG GMRS HT

Antenna Topics 72Building Verlical Antennas

Experimenters Workshop .,..,.,. .,..,..,. 74Handheld Scanner Backlight Mods

PCS Frontline ,.,.,..,. ,.,..,.,.,.,.,.,.,.,.,.,.,.,. 76Marketing Strategies

Federal File ,..,. ,.,.,..,.,. ,.,. ,.,.,.,.. ,.,...,.,.,. 78Smoky Mountain Monitoring

Plane Talk ,.,. ,.,.,.,.,.,.,. ,.,.,.,. ,.,.,.,. ,..,. .,., 80Tools of the Tower

Whars New .,. .,._,..,. .,. ,.,. ,.,.,.,.,. .,.,.,.,.,. 82Review .................................... 85

Palomar Loop Antenna SystemSca nning Equipment ,..,.. ,.,. ,..,. ,..,..,. ,..,., 86

RCA RP-6150 ScantrukMag ne Tests ,.,.,.,.,. ,.,.,.,.,..,.,.,.. ,..,.,.,.. 88

InterNationalWR-689Computers & Radio .,.. ,.,.,.,. ,.. ,.,.. ,...,.,. ,. 90

WiNRADiO uxx vs. leomPeR /000letters , 92Stock Exchange 94Closing Comments 96

Whatever happened to hydronics?

Washington Whispers .......................... 4Communications 6Scanning Report ,......... ... .............. ...... 26

Why We DoWhat We DoUtility World ,. ,._.,.. 30

DoesAnybody Know the Time?Digital Digest,......................... .......,. 33

Mode of theMonth - SITOR-BGlobal Forum ,,..,.. ,.,. ,,...,. 34

More Catholic Than Ihe Pope?QSL Report ,.,. 38English lang SW Guide ,.,.,. ,.,. ,.,.,.,. ,.. 39Propogation Conditions ,.,.,.,. ,.,.,.,.,..,. ,.. 60

HF Propagation BeaconsProgramming Sporlighl ,.,.,.,..,..,.,..,..,.,. . 6 1

Eavesdropping on AfricaBeginner's Comer ,.,. ,.,.,...,.,.,..,..,. ,.,.,.,. 62

Get with the Amateur ProgramAsk Bob ,.,.. ,.,.,. .,.,. ,..,.,.,.. ,.. ,..,. ..,..,._,.. 64

Preparing Those Trade-insBelow 500 kHz ,.,. ,..,..,..,..,. .,..,.,.,. ,..,.,.. 66

19/2 RememberedAmerican Bandscan 67

Ice vs. TowersOuter Limits ,.,. ,.. ,.,.,.,.,.,.,.,.,. ,.,.,. ,.,.,.,. ,. 68

How to Hear a Clandestine

DEPARTMENTSMONITORING TIMES1155N, 0889-5341 ;CPC IPM Sale,Agreement # 125 34921is published monthly byG rove Enterprises , Inc.,Brasstown. NorthCorolina , USA.

Address: P_O. 80x 98, 7540Highw ay 64 West,Brasstown, NC 28902-0098

Telephone: 17041837-9200Fox: {704} 837-221 6124 hccrslInternet Address : web: www.grove-ent.com

or e-mail: [email protected]@[email protected]

Editorial e-mcil:Subscriptions:

(If-f

New cddreases for the emai l hobby forum s form erly hosted by GroveN et:

EDITORIAL STAFF ~rresponden(e tocolumnists may be moiledclo N\onltoringTimes, any request for 0 replyshould Include on SASE.

Note:The Grove Enterpri ses internetc ddress is chang ing. To lind a ll yourfavor ite poges follow the links fromwww.q eeve. net , o r try the newaddress www.qrcve-ent.cc m to findthe M oniloring Times web pages a ndupdates on these email forums.

........ George .Zeller@acclink .com

........ [email protected]

Frequency Manager Ga yle Von Horn goyle@grove .netFrequency Monitors David Dotko. Ma rk J. FineProgr am Ma nager Jim frimmel frimmel@storlexl .nelAmerican Bcndsccn Doug Smith, W9WI .. 72777.3 1.:13@compuserve .comAnd More! Jock Elliott KB2GOM .. Iighlkeepe [email protected] Topics W. ClemSmall, KR6A .. d [email protected] r's Corne r T.l . Are y, W B2GHA Ijar ey@mosquila .ca mBelow 500 kHz Kevin Corey, WB2QMY KCorey@mdsroc .co mCom puters a nd Radio John Ca talano i-ca lo[ono@co nkne t.comDig ital Digest Bob Eve ns . . reva ns@tota l.netExperimenter' s Wbhp .. Bill Cheek bcheek@son .rr.comFederal File .. John Fulf ord, W AAVPY [email protected] mK.I.S. Radio Richard Arla nd , K7SZ [email protected] tMagne Tests .... ....... ... lawrence MagneOn the Hom Bonds Ike Kerschner, N31KO uter limits George ZellerPCS Front l ine . . Don Veeneman .Plane Talk Jea n Boker, KIN9DDProgramming Spotlight Joh n Figlioz zi , KC2BPU john fig@eor thlink.netPropag ation . J a c~ues d'Avignon . [email protected] Sl Comer.. . Goy e Von Horn . gayle@grove,netScanning Equipment Bob Pcrnc ss. AJ9SSca nning Repo rt .. . Richard Barne tt .. . [email protected] Broadca sting Glenn Hauser ghaus er@ha tmoil.co mSW Broodcost logs Gayle Va 'l Horn gayle@grove .ne tUtility World Hug h Stegma n, NV6H driver8@ne tcom .comWas hington W hispers Fred Maio , W5YI [email protected]

wun .

ac ars majordomo @patr ia t.ne tamfmtvdx [email protected] .. .. [email protected] 1ist majordo [email protected] .. ma jordo [email protected] tfedcom .. ma [email protected] thec rsct-l . . mo [email protected] tmilccm . .. ma [email protected] tscon-dc . . ma [email protected] ttrunkcom . .. 10 be announced

..... .......... to be announced

Discfa imer :Wh ile Monitoring Times makes on effo rt toen sure the information it publi shes is a ccu rate, it cannot be he ld liable for the conte nts.The reader assumes ony risk for performingmodificat ion o r construction pr o ject s pub-lished in Monitoring Times. Opin ion o rconclusion s ex p ressed are not necessarilythe view of Moniforing Times or GroveEnte rp rises . Unso licited ma nuscr ip ts areaccepted . SAS E if material is to be ret urned .

Owne rsBob ond Judy Grove

P u b lisherBob Grove, [email protected]

Ma na ging EditorRachel Baughn, KE40PD

mleditor@grove .n et

Assi sta nt Edito rLar ry Van Horn, N5FPW

Art DirectorJohn Bailey

Ad ve rt is ing Svcs .Beth Leinbach

17041 389 -4007beth@grove_net

Busin e ss Ma nagerKelly Davis, KE4TAM

[email protected]

2 MONITORING TIMES Ap,;! 1998

Bearcat Intercepts Trunked Radio

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WASHINGTON WHISPERS

By Fred Maia, [email protected]

Consumer Top 10 Telecom ConcernsDuring the final six months of 1997. thc Federal

Communications Commission IFCC )compkted asurvey and determ ined the Top 50 co nsumer tc fc-co mmu nications concerns . TIle da ta W ..IS collectedbased on nearly hal f a million telephone contactsfrom the pub lic to the FCC s Na tional Ca ll Center(NCC) located in Gettysburg. PA.

Nee. the ce ntra l clea ring ho use for incom ingconsumer inquiries invo lving tele communicati on s.is op era ted by the FCC ' s Compl iance and ln forma-tio n Bureau. The ir lo ll free number is: 1-8XX-C ALL-FCC or I-R8X-.' 25 -5] 22.I) The numhcr onc iss ue W:I S teleph on e t'slam-

ruing." Thi s is the un autho rized swi tchine oflong d istance telephone service . Ca lle rs~areasked to file a co mplai nt with the FCC ' sCo mmo n Ca rrier Bureau a nd to con tact theirlocal telephon e co mpan y and plac e a " PICfreeze" on thei r account. Th is loc ks in thePrima ry lmc rexchangc Ca rrier (PIC) of thei rcho ice and prevent s an unauthori zed ch ange .

2) T he num ber two inqu iry concerned thesta tus of rad io lice nses. gn lll is :md permitsissued by the FCC's lice nsing faci lity inGett ysburg. A mate ur rad io o perato rs in pa r-ticular arc interested in gell ing their ca ll sig nas soon :IS pos sible so they call get on the ai r.But many of the inquirie s concern licenses inother rad io services as well .

3) Disputed telepho ne h ill i n ~ lind se rvice isth e number th re e iss tle. I\'1ns l are co mplain tsabout cha rges for services nut requested ortelephone calls not made . Th ose ca lle rs whocomplain about telephone se rvice orculls madewith in thei r hom e state are ad vised that intr-astate ca lls are not rcgulurcd by the FCC andarc gi ven informu uon abou t how 10 contacttheir state regu latory agency .

oJ) The number ~ consumer issue concerns theTelep ho ne Consu me r Pr ot ect ion Act tlf1991. Con sumers arc an noyed with num cn urstele marketing calls and unsolicited fax mes-sages and want to understa nd the law .

5) H ow to obtai n a Pr-i va te La nd :\I ohile (Bus i-ness Band ) Radio license i!o the number 5issue. TI1C KCC provides information on el i-g ihility, appropr iatc fo rms and fecs and howI II co ntac t Freq uency Cuordin 'llOrs.

6) Inter ferem'c cnm pla in l 'i t il lele" isiol1 r e-ception ranks number 6 . Must are about oroad-cast TV rec eption, but some arc about cahleand satellite services.

7) :\Ia ny ca llc rs inquire w het her Ihc ) ' arc st illr cq u ircd In hold a rad io sln l inn Iit-cnse f{lftheir recreational boat (If aircrafl. The ~CCadv ises lhat the licensing requirc men ts furmost recreali onal stat ions have hee n elimi-nated.

8) Ca ller s with qu est ion s :l lmlil \l'll'phon e in-lerferenCl' arc advised to co nl;u.: t thC' tek -

phon e manufa cturer. Inter feren ce to televi-sion or radio reception from a nea rby A \IIF\ 1broadcast station mayconst itut e a violation of~CC rule s. Callers are asked 10 prov ide spe -c ific informat ion that is referred to the FCCf ie ld offices for in vestigation .

l) I How til beco me a ham radio op erator or torenew or modi fy an exist ing licen se is next.Prospective licen sees arc pro vided wi th infor-mation about o btaining an app lica tio n Form61Ound how 10con tact an Am ate ur Vo lunteerExam Coo rdin ..nor . In fomuui on on reciproc allice nsing ..rrm ngcmcnts with o ther coun trie sand the new vanity call sign program is alsoavailable. The NeC can also provide infonna-lion requirements. qua lificat io n.., and how toapp ly fo r a G f\IRS (Ge neral Mobile Rad ioSe rvice) lice nse .

10) 1\lan)' cullers are upset about th e m eth odsus ed h)' telephone companies to so lici t busi -ness. Th e majority of these co mp la ints con-cern telephone so licitations for switching longdis tance service.

Other Issues of Major Concern t oCallers:

Co mmerc ia l Radio O perat or Llcens lng : ...espe-dally the Restricted Radiotcle phon e Operator' Per mit (RPI and the Ge nera l RadiotelephoneOpcnuors Licen se (G ROL) ...who needs it and howto get the required form s. Where an examination isrequired. Nee provides a list of COI.EM' s (Com-mercial Opcnuor License lixamin arion Managers ).I inw til Olunln FCC Forms : These are availa blefrom the FCC Fonus Cum ractor who can be reacheda I 102-4 IX ,FOR~1.

Op era tor-Service PW" iders IOSP ):~CC receivesmany complaints about rates charged at payphoncsand telephones in public placcv.Mo-t callers are notaware tlun Federal rule s allow customers to choosea long distance carrier when mak ing calls frompub lic pho nes. The Telecommun ication ReformAct g ivcs the FCC power to take control ove r payteleph one pricing fmm state regulato rs.Cable Se rvice Cum plaln ts: ...espec ially inabilityI II conlac l lheir cahk company, poo r customer ser-vil.,c and dt:la)s in making service ca ll!o. There arcman y complai nts about rate incrt:ilses. charge s fo requipmt:nl and t.:han ges in cilblc pmg ramming .en Viola tinll'i: Callers co mplain ahollt inter fer ence 10 t elc \"i ~ i\ln rel'cplioll ort cJcphones cau :c.ed bya enupt:mtor. ~1'lIly C B operator s abo call to reponvinlal i (ln~ nil thc CB channels.Inh.' r nat iOlml T dcpho ne Calls : ... iOl.:ludin!! 80Y(Caribhean) .lfl';!. ~1 any complaints haw hc~n re-ce ived frolll l'allc rs charged exurhilalll rales for callsIhat were unknllwingly plact:d to inlemalionalloca-lions. They Ill

Dealers

Canada

Atlantic Ham Radio Ltd.Downsview, ON(416) 636-3636

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USA

Advanced Digital SystemsSt. Louis, MO(314) 791-1206

Amateur Electronics SupplyMilwaukee, WI(800) 558-0411

CB CityWesthaven, CT(203) 932-3832

Electronic Distributors Corp.Vienna, VA(703) 938-8105

Grove EnterprisesBrasstown, NC(800) 438-8155

RadiowareWestford, MA(800) 950-9273

Scanners UnlimitedSan Cartos, CA(415) 573-1624

SSB Electronic USAMountaintop, PA(717) 868-5643

The Communication SourceArlington, TX(800) 417-8630

The Ham StationEvansville, IN(800) 729-4373

Universal Amateur RadioReynoldsburg, OH(800) 431-3939

Professional WirelessOrlando, FL(407) 240-2880

Radio CityMounds View, MN(800) 426-2891

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Prayer: PersonalCommunications Service?

The frequencies between 930 and 931MHz belong to the narrowband personalcom-mun icat ions services (peS) for pag ing andmessagin g application s. Whil e lookin g upwhat Kobb had to say about this band in hisauthoritative Spectrum Gu ide . assistant edi-tor Larry Van Hom stumbled ac ross the fol-lowing anecdote- appropriate for an Aprilissue! We quote here from Bennett Kobb:

"The strange Space Shot service oncetriedto get acce ss to this band. Space Shot calleditself 'The Interplanetary CommunicationSystem That Links You To The Universe.'

"Space Shot helped customers ' search forextraterrestrial life ' by sending love notes orpeace messages into space on 903.0 125 MH zfor $5 per 'launch .' Its purveyors held atemporary, experimental license. Th e FCCdeclined its request for permanent status at930 MHz in 1985 ... indu stry commenters

Ap ri l 3-4: Marietta, GA2nd annual South easte rn VHF Society

Technical Conference at the AtlantaMarrionNorthwest.Technicalpresentations.antennameasurements, noise figure testing, fleamarket(Fri evening).banquet.auction.Con-ference fee $35 at door. SVHFS. PO Box125 5. Co rn elia, GA 30531 or Bobk4sz @stc.tiet, 706-864-6229.

April 4: Fredericksburg, PAAppalachian Amateur Radio Grou p

hamfest at Northern Lebanon High School(1-81 exit 30, PA72 south 10 US22. E on 223 mil. Talk-in 146.04/64. 8am-? admission$4. VE testing, forums, concessions. Con-tact AARG, 105 Walnut St, Pine Grove, PA17963. 7 17-345-3780.

Apri l 25: Special Ev ent StationSpecial Event Station N4C commemo-

rates the only US boundary in which fourStates share a common point-Arizona,Colorado, New Mexico, and Utah. Eventcoincides with the NorCal QRP Club's fieldtheme "Run to the Borders."

Times: Apr 25. 2200 UTe to Apr 26.1700 UTC. See bllp:/Iwww.swcp.coml- n5zgt1or email [email protected] informatio n, #10 SASE & QSL re-quested to N4C, do WASWHN. Jay Miller,

6 MONITORING TIMES April 1998

COMMUNICATIONS

"How gratifying it is to have such afine turnout/or our weekly UPLINK!"

ca lled it '3 radio version of the Pet Rock. '"A Vermont company has resurrected this

concept. Its Prayers Heuvenbound servicetransmits religi ous messages into space for afee.

'Ollr exact communicatkmsf requency to

PO Box 6552 , Albuquerque. NM 87197-6552

April 24-25: Li ll ie Rock, AR1998 Little Rock Hamfest at the Expo

Center. 2 mi. southwest of Little Rock on 1-30 . Huge, inside flea market, Morse compe-titions, homebrew contests, VHF fox hunt.banquet, weather spotter certification, tech-nica l assistance. prizes, etc! Talk-in 146.850.Admi ssion $7 ; 4-9pm Fri. 8am-5pm Sat.Co ntact Little Rock Harnfest, 1008 Pine St,Arkade lphia, AR 71923-49 19 or vis itwww.aristoUe.nel/-n5xoyllrh98.html

May 2: Cedar burg, WIOzaukee Radio Cl ub 20th Cedarb urg

Swapfest at Circle-B Recreation Center, Hwy60 and Co. [ (20 mi. north of Milwaukee ).Talk-in 146.37/.97 and 146.52. Admission$4, 8a.m. to Ip.m. VE testing. forum s, con -cessions. SASE to ORC Swapfest Chairman .W5 8 N985 Essex Drive. Cedarburg, WI53012-1 439.414-377-2784.

May 2: Owensboro, KYOwensboro ARC 6th Annual Hamfest at

Sportscenter, 1215 Hickman Ave. Talk- in147.811.2 1. 146.265/865 alt. Admission $5.8a.m.-? VE testing, forum s,co ncessions, sur-plus auction at close of hamfest. Co ntact

God's Hea ven is the result ofmuch researchand is theref ore proprietary? the companytold us. 'Our prayer uplinking faci lity is notlocated on United States so il. or within any ofits possession s. As such, its existence or RFemi ssions are of no jurisdictional concern ofthe FCC"

Sky RepeaterThis idea strikes us as a real cas tle in the

air, but Angel Technologies is a small co m-pany in St. Louis with very high hopes. Th eyenvision making high-speed Internet and dataaccess available to everyo ne within a 50 to 75mile radius by means of specially-equippeduircraft circling 24 hours a day,

Angel Technologies doesn't plan to bidfor auctioned spec trum, but hopes 10 team upwith other companies that hold frequencylicen ses . Likewise, they don ' t plan to designthe serv ices being deli vered, but hope to teamup with other companies that hald the li-ce nses to provide wireless services,

George Stokes KD4CKT. 1218 W. 3rd St,Owensboro, KY 42301, 502-683-2 169.w4nho@occ~oky, camplls,mci.net

May 3: Hagerstown, MDAntietam Radio Association's

Hagerstown Hamfe st Bold and ComputerShow at Hagerstown Junior College Corn-munity Center. 1-70 exit 32B to EdgewoodDrive. right at Federal Bank, college 1.4miles on left. Talk-in 147.090+. Admission$5. 8a.m.-3p.m. VEtesting9 a.m. (no charge.walk -ina accep ted), forums, co ncessio ns.Contact Don Jones KB8W HW 304-728-7769 .

Club News: Radio Moni tors of Maryland has an onlinec ha t room o n the club's pagewww.arrowweb.comlRMf\.I. Look for"RADIOCHAT ' on the opening page: RonBruckman ("Editor") will be online occa -sionally, or you can visit anytime for generaldiscussion . The radio email forum s which have beenhosted by GroveNet have been moved , sincethe internet service has been sold and Groveis now a customer, not a provider. See page2 for new addresses. or visit www .grove-ent.comlmajordomo.htm l for the latest up-date.

COMMUNICATIONS

~~ 150 ExecutiveParkBlvd.14600 San Francisco, CA94134Fectory Duect Phone: (4151468-2066 Fax: (4151468-2067 'Since 1971 '

So might read the bott om line from themost recent Board of Direct or ' s meet ing ofthe American Rad io Relay Leag ue.Th e Board,which last fa ll came out aga inst eliminatingthe Morse co de requ irement for HF (short-wave ) privileges. thi s wi nter voted not tosuppo rt restructuring of the ama teur radiolicen se t: I:.ISSC S to crea te fewercl asses. and notto gra nt inc rea sed pri vileg es to the Novicean d Tech nician classes.

Th e Board d id vole yes to renaming theTechnical Ex ce llence Award the "Do ugDeMaw Technical Excellence Aw ard . Now,the re ' s something we can support:'

wa re and software-c-which is wha t ham radiois all about .'

Hams (a nd tech nica lly -incl ined rad iomo nitors!) arc invited to co ntact Dr. Shuch tolearn mo re about how they can support whatis no w a private. nonprofit e ffort since Con-gress termi na ted SET l' s fundi ng in 1993.Call the membership hotl ine at 1-800-TAU-S ET! , fa x 20 1-64 1- 177 1, or e mai ljo ;"@ ,H, tih ag ue. o rg. T he ir website iswww.sctlleugue.org.

T he May issue of Satellite Times w illfeature a co nstructio n a rticle on ho w to builda simple SET I monitoring station.

"IOO-Year-Old Hobby Votes No"

we welcome news clippings fro m lourwnrld of ra d io. Send to edi tor Rachel Baughn;,) 1 ,\11' headq ua rte rs . o r e -ma i l toIIl1f 't lito,.@grm(' . lIel .

T hanks In thi s month ' s repo rt ing tea m:Anonymous. FL and NY; Refe Barber, MI ;Den nis Drissi. CA: Kenneth Dupuis, NY; A.B.Frasco. IL: R.Glenn Jones. GA; Kevin Klein ,WI; Don Loving. OK; James Macfr onald , NH;Maury Midlo. T X; Doug Robertson, CA; MikeRoth . IL; Richard Sklar. WA; Larry Van Horn.NC: Elmer wallescn. IL ; W5YI Report

~~w""',.,.HOUR "BUILT UKf R BRTTLfBHIP" Heavy dutycommercial recorder -

NOTimprovisedtromconsumer models. 12, 14.and 16 hour models alsoavailable

BUILT-INvoice activation (add $30) Applicat ions information included

Oimensions: 11 5 x7.0 x2.75'

--

So, the hamsare gellinginvolved illSETl- YUM, Ilike the soundof that!"

gimmick. and sometimes they don ' t ag reewith his views. but , says local store-ownerRalph Miller. " He takes them ..rll o n. Listen.he has no voice . It wa s eitherdo this ordie . Hefound somethin g to do."

According to Shuch. "hams have contrib-utcd to virtua lly every breakthrough enjoyedby the telecommunications industry . includ-ing the: devel opmen t of the: Internet. ... Nowthe ama teur radio co mmuni ty is rev ita lizingitsel f by applying its mem bers' talents insearch o f other life in the CO~1110S :'

"S earc hing for life in space requires thckind of rad io skills whieh ham s po ssess ... ltinvo lves the design and co nstruc tion of an-tennas. rece ivers. anti signal analysts hard-

So reads a pre ss release from Dr. Pau lShuch. Exec utive Directoroft hcSET I Leag ue.The head line refers to the league ' call forama teur radio voluntee rs in its search forex tra -te rres trial intelli gence (SET I).

"IOO-Year-Old Hobby Takes onNew Life"

Docs this remind you of a certain plan(called Sky Station )to usc blimps as towers inthe sky ?

Apparently a pnH()(YI~ ofthe spec ial planeis be ing bu ilt by Scaled Composites-thesame co mpa ny thatcreatedthe Voyagawhichsuccess fully circ led the ea rth wi thou t re fue l-ing. Te st fligh ts arc expected th is yea r.

H nHIHll. is that cloud starting to look like:a cas tle to you'!

" I guess it' s like a blind rucc cur driver: 'typed Dan Lawrence. explaining the atten-tion he gets as a di sc jock ey on rad io stationKHUM FM in Ferndale. Californ ia. Dubbed"Dig ita l Dan," he ' s the only known DJ inAmerica w ithout a vo ice .

Perh aps due to expo:-.urc 10 Agent O ran gewhi le se rving in Vietnam . Dan lost his voca lcords. tccrh. tonguc. musclcsund lymph nodesto ca nce r. Whi le doi ng so me carpentry at theloc al stat io n. Dan acquired a new toy: a dig i-tal synthesizer wh ich con nected to his laptopcomputer , Statio n co -owner C liff Ber kowi tztaped an interview with D"1I1 using the me-chanica! voi ce. and the community responsewas overwhelming.

Dan now hosts the Di\lZ show (Digi ta lM usic Z OIlC) and Fra nkly Zappa (two hoursfrom his collectio n o f 1.l lJ-l- se lections ), andshares his often con trove rsia lopinions. Some -times new listene rs will th ink the voice is

Scanner for a Reason" Now that th is happen ed : ' says Roxanna

Shee ts. "I' m glad that I bo ught it:' What shebought was a scanne r. purch ased i.IS a Christ-mas present for her husband IJavid out of hermeager ea rni ngs.

Even in Cali fo rnia the nights can get co ld.and o n one of the coldes t nights last win ter inLemon Grove nca r Sa n Diego a homelessmother ca lled the Sheriff s De par tment. as k-ing them to take in her two child ren. ag ed 7and 4.

Dep uty Randy Visco nti met the family asthey huddled ncar the pay phone. "S he wasdespera te anti d idn 't know what to do ," hesa id . But as shel te r after shelter reported noroom to take the m in , the office rs and di s-patc her s were ru nning out of options.

Less tha n a mile a\\,;'I)'.the Shee ts listenedto the situation unfo ld on the ir scanner. andsuddenly the solut ion seemed dear. Sti lldressed in the irnigh tcloth es.t hey drove to thephone booth to offer what food and she lterthey had . " Like they say," S;'IY S Roxanna."God makes everyt hing happe n for a reason."

OJ Without a Voice

April / 998 MONITORING TIMES 7

RadioTransmitter

SitesThe completed tower array at KLTT. 670 kllz, Commerce City. CO.

The base insula/or anti tuning/matching II Il it for all ,LU tower,

By Patrick [email protected]

ne of my hobbi es is identi fyin gand photographing Al\I radio sra-lion transm itter sill'S. I always

li nd it im pressive to look ut the an te nna tow-ers a nd thin k ab out how lIlallY peo ple. ove rva st di st ances. may be listening 10 the signa lsemanating from the site I am vie wing .

I have fou nd that man y people. es pec ia lly

those ne w ((l t IIC hobby. aren ' t uwurc that at anA~1radi o stat io n the (I)WeTS U()11 "t support thea ntenna, they art' the antenna . This is becauseof the ext remely long wavelengths ;.11 thesefn..-qucncics. For com parison. a 1/-1- wave -len gth ant e nna ut the 4 50 tvlHz public safe tyhand is about f inc hes long . Au he 27 M Hz CBfreq uen c ies. I /..J wave leng th is about 9 feetlon g . But a I /..J wa velength anten na ut 540kl lzat the bot tom oft he A M band is abollt450feet long !

It is usually C;'ISY to spo t all A1\,1 rad io

station to wer. If it is a to wer that uses I.!U\wires , the wires will be insulated from thetower nea r the attachment points . The guywires will a lso be di vided in to severa lnonresonant sec tio ns by in sul ato rs. This pre-vents the guy wi res from interfering with thesigna ls co ming fro m the tower.

In most ca ses the tower w ill be sitt ing 0 11 alarge insul ator (see pho to be low . left ) at itsba se . T hat is a sig n of a "s eries fed" towerwhich is the most co mmo n type o rAM broad-cas t towe r. T he: exce ptions to this a re "s hu ntfed " tower s whi c h have a grounded base .An othe rcluc is multiple to wers in close prox-im ity to eac h othe r. Multiple tower arrays (seeph uto ab ove, a simp le ex ample ) are A!v1 di-rcct ion al ant enna sys te ms .

Antenna Design on a Grand Scale

Many cons ide rations are in vol ved in deter -min ing the size , number. and orientation ofthe towers. These fact or s ar e de termined bybroadcast engineer s who specia lize in thi saspec t of radio sta tio n design . So me of theite ms which m ust be co nsidere d a re thestation's freque ncy, its power, and the direc -tiona l pa tte mts l required . Many broadcas tengineers tod ay re ly on computers to mak ethese co mplex determinat ions.

In its most ba sic form. a low power.non d ircctional . loca l se rvice AM station on

8 MONITORING TIMES Ap ';/ / 998

one of the higher frequencies Illay employ asingle . shor t towe r. From there things canbeco me qui te com plicated. Many stations arerequired to "protec t" the signals from one ormore dista nt stations 0 11 the same frequencyby di recting their signals away from the otherstation 's cove rage area . Or a station' s tran s-miller site may be located at the edge of itsintended coverage area, requiring it to con-ce ntrate more signal into that area.

These problems arc resolved by using di-rectional antenna sys tems. These pattern s canbe quite bash: and require only two towers, orthey can be very complicated with many lobesand may necessitat e anywhere from three to12 or even more towers.

Because of the changes that occ ur in theionosphe re when the sun is no longer visibleat the antenna site. signals in the AM bandtend to travel much farther at night. Thi sfactor requires many stations to use differentpower levels and antenna patterns at nightfrom those used duri ng the daytime hours.Some stations also have different antennapatterns and powe r levels J uring the "criticalhours" - two hours befo re local sunse t andtwo hours after local sunrise.

Or, a station Illay have a pre-s unrise orpost- sunse t author ization that requires stillano ther set of power and pattern settings. Forexa mple. a particu lar statio n may operate with50,000 watts and a nondircctional antennaduring the day. then switc h to 1.000 watts witha directional pattern during the cr itical hours.then switch to 50 watts with a still di fferentd irect ional pattern at night.

This complex seven-tower array near Cheyenne, WY, is actually two A ll! stations.Three towers are fOT a stat ion on 650 kHz and the other four are for a stat ion Oil15311 kHz. Below is a nighttime radiatio n pattern for a Utah station 011 111611 kit:..Courtesy National Radio Club .

I Prime Siting

Another unusual aspect of AM radio slavtion construction is that the transmiuer sitesarc frequent ly built on low. wet ground ratherthan the high ground preferred by FM stu-tions. That is because the ground becomes animportant aspec t of the antenna system atthese low freq uencies and the welter theground. the more conductive it is.

In fact. the gro und is so important to theoperation of AM stations that they arc re-qui red to place a systemofground wires undereach towe r wheneve r possible. This groundsyste m must, at minimum. consist of 120wires spaced at 3 degree intervals and extend-ing at least 150 feet from each towe r base .These radia ls are usually heavy copper wireburiedj ust below the ground (sec photo at left)to protect them from damage.

Because or the importance of a highl yconductive ground system. many AM stationsgo to extremes in the placement of their tow-ers. That is why these sitcsurc oftcn placedncar, or sometimes in. streams. rivcrs. creeks,marshes. swamps. lakes or oceans. and arefrequently remote from the act ual stat ion lo-ca tion.

I recen tly had the uppor tunity to observethe const ruction of a new AM station beingbuilt near Denver. T hanks to Bill Johnson ofRocky Moun tain Erec tion Company in Okla-homa City. I was given an inside view of theman y aspec ts ofbuilJ ing such u facili ty. This

April 1998 MONITORING TIMES 9

particu lar station was to become KLTT on670 kHz licensed in Co mmerce City. Cole-rado. It uses a directional antenna sys tem(see photo on p. 8) with four 363 foot towers.KLIT' s license requires it (Q use differentdirectional patterns during the day and nightcoverage periods. The daytime pattern uti-lizes three of the towers with a transmitterpower of 50 .000 walls. The night patternrequires all four towers with a power of1,400 watts.

Whose Transmitter is it?

In most cases At\'1transmi tter sites do nothave signs iden tifying the station. usually forsecurity reasons.One method Ihave fou nd todeterm ine which station I am looking at is topark near the site. remove the antenna for mycar radio from the veh icle. tum off the DX ordistance switch. then place the radio in theseek position. The radio will usually "fi nd"only the nearby transmitter. Of course thestation must be on the air when you do this.

It is also a good idea to scan past thestation to sec if the radio might find ano therone. With the expense of real estate andantenna towe rs increa sing on a daily basi s,many stations arc now sharing towers withother stations by means ofmultiplexers whichallow more than one station 10 use the sameantenna at the same time.

Above all, remember to m ! l ''r trespassonto the radio station's property. Aside frombeing illegal. it can also be hazardous to yourhealth due to the high energy RF fi eldssurrounding the lower and its buried grou ndsystem.

Happy hunting!

10 MONITORING TIMES Aprd 1998

Materials for all A M tower include a set of lights and a roll of wire mesh which ispart of the grounding sy stem.

The antenna, phasingand tower lightingcables fo r the fourtowers at KLTT cometogether ill a pit behindthe transmitter buildingduring construction.

KLTT tower # / is on theground awaitinginstallation as tower #3nears completion ill thebackground.

(Re)lnstalling the Oak Tree Antenna

The first item on o ur list was to toss a guyline up over the high est tree branch in l ilt: oaktree. It turn ed out that the tallest tree hadgrown eve n ta ller du ring the ensuing year.

The cas ual toss was now to be a full-blownthro w o f about 50 feet up to loop the line overa de sirab le bra nch of the heig ht requ ired. So nRandy, bein g the youngest and with the bestpitchin g arm, was elected to do that.

Th e perfect weight was an old pulley wefound in the j unk bo x. To this we tied on e endof some light-weight nylon cord. My so n tr ieda few throws but was thwarted when his dogdeci ded to take a nap on the loose co ils. Withthis limiting restrain t on the ny lon cord, backdro pped the weight. missing the poor houndby an uncom for tab ly close margin . We thense t in place Rule # I: keep pets, child ren , andother peop le clear of the area. Rule #2 is goodalso: wcur prot ect ive helmets if yo u havethem.

On the third try . the weight fou nd a lowerlim b instead o f the one we had voted on asideal. As the laws of phys ics d ictate. theweight-s-acting in somewhat of a "bolo" fash-ion-wrapped the guy line fi rml y twice aro undthe lim b.

No pro blem. we co uld hand le that. Ta kinga defens ive position behind the hou se, wepulled and pulled on the co rd. trying to ei therbreak the line or pu ll the pulley free of theclut ches of the branc h.

We misjudg ed both the strength and thestored pote ntial energy in the stretched nyloncord. We had ex panded the length o f the cordanother third o f its length be fore the narrowbranch broke. Th e pu lley shot outofthe tree atan ama zing speed. W ith a resounding "crack: 'it stru ck a hard blow to the side of the house.

2 FT. LENGTH OFLIGHT COTTONSTRI.N:.;G;;..--....

ANTENNA NYLON COROGUY LINE

"Toss a guy lineup over thehighest treebranch in the

k "oa - tree.

TREEGUY LINE

_---WEIGHT

By Arthur R. Lee, WF6P

FIGURE 1

The task

We care fully examined the an tenna andlend -in. Aft er we straightened out a kink ortwo in the stranded co pper wire. it was intact.No problem here. All we had to do next wasIII run a co uple of new gu y lines in the tree toge t the ant enna back up in the air where itbe lo nged.

/ 1 _V PULLEY

FIGURE 2

/ Lle111 k

I What we found

Orig ina lly " tn lllg be twee n two large trees.the an tcnn ..1 hall been down since Ia"t win ter.The ny lon guy lines had bee n damage d by theultra viole t (U V) rays o f the sun. plu-, thesway ing and wcur ac tion of the trees. O IlC ofthe old guy lines- the one in the II;gl/('.\{ tree .of cou rse-c- had part ed . Additi onally. it hadsomehow gotten wra pped up in [he rotor bladesof the lawn mow er in the first ", pring mowing .0 11 wel l. things like this hap pen !

l;lC]"L' probably i" ll' ( uu cavicramcnnn II Iput up than an uld-fus hioncd ~() rueterdipole . or CO UI'S\.'. i f it i.... one that 11:1 ";

been down for it couple of ye ars. that is ad ifferent stor y ~ This w a-, the ease for my sonRandy. N6UZ I.

With a new baby in the household. he andhis wife Cybclc. KC6ZQ S. had been usin gtheir time for a more noble purp ose. thai oft hecare and feeding ora young infant son (No . theson do cs n 01 ha ve hi s ham ti...k c t yctl ). Wh enthey to ld rue o f thei r need to ha ve the wi rehack lip. friend Stuart Keller. KlJWNlJ. and Ifle w to the ir as sista nce.

Ap6/ 1998 MONITORING TIMES 11

.fANTENNA

PLASTICBUCKET

ROCKWEIGHTS

FIGURE 3

FIGURE 4

~---- PULLEY GUYLINE

8' POLE

fccdlinc co ax at the tran s-mine r e nd into hi s jvlf-JMod d 2St) SW R Ana-Iyzcr. According to theanalyzer's readi ngs. theantenna was trimm ed cor-rec tly and read ab out I: 1.5o n the desi red frequenc yo r 7. 155 MI-It.. Wecould n't ask for mu c hbet te r than that. Now m),so n and hi s wife are se tfo r som e nice long QSOs !W ho know s? Maybe soonwe can a lso talk to ourgrandso n. Beckett.

"To the end ofthe antennu guyline we attacheda plastic bucket.filled with justthe right numberof rocks to holdthe antenna in ahorizontalposition."

W ith the ante nna bac k in place . we chec kedthe guy line in the smaller tree . A tall ladderallowed us to ge t up into the sma ller brunche sto cut away new growt h bran ch es and leavesth aLwere in contact wit h the anten na wi re . Nothav ing a profes siona l tree- trim m ing tool. wema de our own (figure 4) .

leavi ng a scar in the wood . Wc were a ll we llclear, but Stuart joki ngl y said. "Well. thatli tt le damage is something that could be eas ilycovered by a 4 by ~ sheet of plywood , nailedin placed and painte d!"

Thus the " bre akable link " wa s re invented(fi gu re I ), whe re a two fool le ngth of lightcotto n stri ng was made to jo in the weight andthe throwin g line . A sharp tug would ea silybreak the st ring and allow the we ight to returnto earth for ano ther try .

Ano the r th ro w pu t the guy line success-fully in place ove r the correct bran ch. We thenattach ed a sma ll pull ey to the antenna (figure2). Through the pu lley we pa ssed the an tennaguy line. the n haul ed up the tree guy line to thehigh est poi nt.

To the e nd of the antenna gu y tine weattach ed a plas tic buck e t fi lled with just therigh t number of rocks to hold the antenna in aho ri zontal position . Holes in the bucke t pre-cluded it fro m act ing as a rain-catcher (secfigu re 3 and side ba r sto ry' on co unterweights).By ad ding or subtrac ting the we ight in thebucke t. we were ab le to kee p the buck e t sus-pe nded. Its weight exe rted the pro per te nsionon the anten na to allo w a " rain loop" in theco ax feed- line (figure 5).

The proof of the pUdding

To lest the sta nd ing wave ratio (S\VR) ofthe ante nna . S tua rt p lugged th e a ntenna

The finished job

Weighted bucket maintains tension01/ antenna, compensating finmovement of trees and wind.

Feed-line "rain-loop" preventswater fromflowing down thecoax and entering uttic.

FIGURE 5

12 MONITORING TIMES April /998

Two Counterweights for Tree-Supported Dipoles

FIGURE 2

.--- ,

L ANTENNA

FIGURE 1

the ante nna guy to one end of the post. varyingthe attach point unt il the post was at a 35 to 40degree angle with the ground (figure 2). Theweig ht exe rted by the POSI kept the antenna atthe desired height. The swaying of the treebranches lifted the post, then returned it to itsangular position. In any case, the antenna wasfree to move without putting undue strain onthe end guy s.

These two easy solutions to keeping yourtree- supported antennas "tight" and withoutdamage cost nothing. Moreover, they cer-tainly have proved to be effective. No morewalking out onto my back deck after a stormto see my 80 meter wire draped across my wetroof, useless and inoperable. Let the Apri lwinds blow!

PULLEY

I.~__ J\

ANTENNA GUY

J 1

,--

TREE GUY 1i

'- ..--TREEGUY

-1

By adding a rope hand le. it co uld be at-tached to the counterwe ight line of the an-tenna. The addition or subtrac tion of a fewrocks would balance the weight of the antennanicely. The drain holes wou ld serve to preventany accu mulation of rainwater (figure I).

The old fence post trick

The buck et full of rocks worked nicelywhen dealing with a relatively short 40 meterdipole. However, the location. length andweight of my 80 meter dipole was a differe ntcase and ca lled for a different strategy. Whensett ing up this counterw eig ht, the materials athand were limited until I ca me across an oldfencepost.

The heavy post was perfect! I simply tied

A method that is not so new presented itselfwhen I was strugg ling with the problem ofsetting up my son's 40 meter dipole (seeaccompanying article). Voila! A plastic bucketwas near at hand . More specifically, it was abuck et in which a potted plant had arriv ed athis household. Con veniently.drain holes werealready present.

There is more than one way to skin a cat-or hold up an antenna.

There used to be a saying amo ng hams inthe early years that a tree was an integral partof a dipo le antenna. This was probably theresult of a universal absence of funds forpurchasing the towers, roto rs. and beams wenow have in abunda nce . Eve n today, how-ever. we find that ma ny hams still use conve-nient trees to support one or bot h ends of theirdipoles.

I own a 40 foot tower which supports itsown three element bea m and 40 meter dipole.It does this without the aid of a tree. but doesde pend upon a fence post and porch rail tosecu re the end guys. My 80 meter antenna,however, is another story. Due to its greatlength (125 feet) it extends from my garage tothe large tree on the edge of my property.

The standard method of attaching the guysto a tree wo rks quit e well - there is nothingnew here. Yet , if the counterweight is not "j ustright," the raging winds of winter may causethe trees to sway heavily. pulli ng and rippin gyour antenna away from the mast and othersupport.

After experimenting with a few counter-weights which weren' t "right," old mothernature beatme two winters in a row. Thewild ly sway ing lim bs of the giant Eucalyptustree were too much for the metal retainingmast Ihad construc ted on my garage roof. Thejerk ing and pulling easily snapped a wirecable afte r collapsing the supporting mount.

One of my early attempts at making acounterweight was that of using a green log. Icut it to the right weight and ran an eyeboltthro ugh it. Fine. It looked and worked well fora while, until the log dried out and lost itsweight. My 80 meter wire then sagged downonto my rooftop. snagg ing under my shingles.Heavier logs put too much of a strain on theantenna. A sack of rocks was tried next , butafter a while the sack rotted out, spilling theroc ks out onto the grou nd. My antenna endedback on my roof. Hmmm ... what to do ?

The old oaken bucket

T Ie Quickie, Snap-onTower Bracket

36"

Hole forPulley orAntenna Wire

Details ofslot placem entand dimensions forRohn 2S tower.

FIGURE 1

The steel cuts easily with a hacksaw. TheRohn tower uses 5/ 16 inch rod for structuralbracing. so for the end slot. drill a slightlylarger hole-l recommend 11 /32 to 318 inch .Then saw out to intersect the hole at the sidesand remove the excess metal. You may needto dress the slot with a file. See figure I.

To make the elongated slot, drill adjacentholes with the same drill to about 1-1/4 inchlength . Saw a 3/8 inch access slot as before,removing excess metal. Refer to figure I. Youwill need to file or grind out the rough spotsalong its length. Th is work is more than com-pensat ed by the snug fit and ease of installa-tion later.

Some may regard the elongated slot as toomuch work. The bracket. with only the endslot. may be installed. but it will angle upslightly. Though not as attractive, it does givea few inches more height at the end of thebracket. Without the elongated slot, however,this bracket definitely muse have additionalsecuring CO be safe.

Either design is great for emergency ortemporary use, such as for Field Day or aDXpedition, increasing the tower use for sup-porting antennas. It also may be consideredabout as permanent as any other antenna as-sembly. It may be installed or removed with aminimum of time and fuss.

Not to Scale!

I used 3/16inch by 2 inch mild steel stock.An overall length of 36 inches gives a two-foot clearance from the tower. You may drilla suitable hole at the far end to attach a pulleyand insert a halyard. When you climb thetower. you may haul up the bracket assemblywith that line; or you may dispense witht hepulley. attach the insulator directly and use

the wires to hoist the assembly.The bracket fits levelly across the

tower and snuggles up to one tower leg.It is optional whether you secure it

further, but it isgood safety prac-tice and installation proce-

dure to wire each end tothe assoc iated tower

leg (see figure 2).

Construction

so long as there is a downward pull andreasonab le tension from the antenna . One canuse wire to secure the bracket to one or twolegs, providing additional insurance againstmovement .

The legs of a dipole will act as guy wires,effectively securing the bracket. If you installa small mast-mounted antenna, the additionalsecuring is a must. The required U-bolt maybe installed on the ground, reducin g workoperations performed on the tower.

By A.W. Edwards, K5CN

View ofhow bracket is inserted and moun ted.Additional securing may be done at legs A andB with wire.

The antenna bracket described here of-fers a quick and easy method to supporta shortwave antenna or multiple anten-nas off your exisitng tower. You could add acenter-fed antenna or configurations of singlewire antenna s-whether slopers, trapped an-tennas, or verticals-at various angles to thetower. Itmayalsosupportsmall.mast-mountedantennas-VHFIUHF scanneranten-nas, discone s, small yagis, etc.

The bracket was developed to takemost of the work out of attaching anantenna support to the upper sectionsof a tower, where working conditionsoften are difficult and uncomfortable, and thehardware you carry along is subjec t to drop-ping. This installation uses no hardware .

The dimen sions shown are for a Rohn 25tower, but these may be changed so that theslots will fit other towers. The finished bracketdrops neat ly into place and locks fairly well.


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ing and feeds the rad io thro ugh the coax wirethat a lso conducts tuning hias fro m the co ntro lbox to D I ,

Th e sole dut y of this loop is now weat her-fax, The sharpes t selec tivity tbig hcst-Qj is atthe low frequency end and co vers the 5 . 10MH z hand , However. Q decreases hy theamount of co upling int roduced throu gh C LLess coup ling im proves Q. selectivity andgnin - up 10

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It has sharp nul ls when rotated while sur-rounded with house wiring. T his shouldn' tbe, but it doesn' t kno w that ! Maybe nulls willbe absent in your home. but do move it aroundif your antenna 's per formance seems suspec t.The high end of its range of course suffersfrom a loss of sharp resonance peaks as withthe big loop.

On e day my mind snapped and Inamed thislittle desktop the " RHOT ENN A." I wouldenjoy hearing from those daring to make one !

Th e circuit show n in Figure 3 is a super-mouse. It is quick to make and not cranky atall to co mplete and operate, 5/16" woodendowels for the frame have 6-32 bra ss screwsthroug h the dowe l e nd s wit h 1/8" o r111 6" X 20" bronze bra zing rods sol-dered to them . Did I calculate di-mcnsio ns'!Nope. justestimated!

The secondary can be madeof any barcor insulated wirea nd thread s th ro ughholes in the dowelsa nd anchor at thecross- hub. The sec-onda ry co uld also be arod duplica te of the mainloop. Any feed wires are okay .Expcr imentin g with zip-chord andaudio cable found no difference.

Second ary spacing from the mainloop can he anywhere from 112" to I"without noticeable perform ance changes.Thedrawing is schematic only. The main loopends should be brought toward eac h other andsoldered to two brass screws that pass throug hthe usual Radio Shack project box con nectingcomponents and 9 volt battery . Do observeproper polarity beca use varicaps arc cra nkyabout reversa ls.

Silting on my desk, always ready to per-fon n during storm approaches. the loop 'sresponse to lightning discharges is very poor.

The Original Desktop Loop

Silicone Sealing the Component Box

All box entrances including the panel andbolts are sealed against weather with G.E.Silicone 11. Thi s is an ammonia cu ring com -pound that neve r corrodes internal pan s.(Sm all tubes are avuilable .)Avoid substitutesbecause some contain ace tic acid and its va-por will silently destroy metal parts, espe-ciall y iron. Sea ling both sides of the endsagainst the box co mpletes the job.

band . Through the receiver, tuning the upperarea with the varicap finds peaking noiseabsent

\Vith such limitation was it worth the ef-fort? Abscl utely! If you live in an electrical lyno isy area, signals bang through virt uallynoise free. Also , looking ornamen tal andmounted only six feet abov e ground, zoningsnoops arc not likely to notice.

Another trait of the single-tum loop isbrnad siding arriving waves; all ang les of po-larization arc add itive at the ter minals. Incontrast, straight co nductors are plane-of-at -rival sensitive and respond to variatio ns withfading. Ionospheric fading can involve bothpolarization and reflect ion angle changes. Theonly rem edy when using straight conductorswould be three antennas oriented on X,Y .Zaxes with a switching arrangeme nt.

Performance vs, Height

There doesn 't seem to be any advantagewhen mounted higher than a few feet abovegro und. It certainly red uces lightning hazard .Since R3 is the only co mponent drawingcurrent. it requires three ye:'lrs to decrease the9 volt bauer)' to 5 'lo lls. Volt age is checkedacross the female coax socket with pot R3 setmaximum w'here a fraction or a volt errorexists.

April' 998 MONITORING TIMES 17

~

ASimple Turntablefor Loop Antenn s

By Richard a . Marris G2BZa

Many enthus ias ts usc ta ble topfram e or fer rite rod loop anten -nas for one reason or another.These loops arc usually directional. using thepeaks and null s in the ir figu re-e ight or car -dioid directi on al po lar reception pattern toaugment a weak signal or dim inish an over-powering one.

Over many years the writer has designedand built table top loop antennas from VHF toVLF . and whenever any o f these have bee npublished . it is usually men tioned that the"loop is placed on a small turntable." Th isinevitably brings a question from a few read-ers. "where can I purchase a small turntable?"The answer. as far as the writer kno ws. is" you cannot buy one-you make it!"

A record player turntabl e can read ily beadap ted for the purpose . On e of my earlymodels (aro und 15 years ago). used the turn -tabl e plus motor from an o ld suitcase typerecord player. suitab ly box ed lip. for loopro tat ion. It wo rked fine. but wa s rea lly tooheavy ami cumbe rsome.

A more recent idea is illustrated. and showsa spin dle located in the ccn tcr ota so lid woodbase (figure I ) o nto whic h a turn table isfitted .

O ld record pla yers arc now very plentiful.

" Why not buy a turntable atyour local store?" The am'weT isthey arejust 110/ suitable.Because they are lightweight,they WWIlDt support the weightof a 36 H by 36 " (or larger) loop.Jlforeov.er, the store turntablewill probably be fitted with free -naming bearings, mak ing italmost impossible to keep theloop turned ill a particulardirection , given the stiffness ofthe coax. A homebrew solutionis the best compromise.

4x rubber co rner feet

o

TOP VIEW

FIGURE 1

The turntable is usually sec uredto a cen ter spi ndle. and hel d inpo sit ion with a ci rclip, which ca nbe pried off with a sma ll sc rew -driver.

O ldertype turntables are usu-ally made from me tal. More re-cent type s arc of mo lded plast ic.Eithe r can be used. A po pularsize appears to be about 28cms indiameter. The most popularspindle d iamete r appears to be 6mm ( 1/4 inch). The underside ofthe turntable often has a circularra ised rim (figure 3) with a diam-e te r abo ut 50c/c, percent of theoverall turntable .

Th e square wood base shouldbe about 18 mrn (3/4 inch) thick,and cut as sho wn in figure I.

\

Rubber or plast ic feet are fittedat eac h comer.

Spindle An appropriate di-

/

Turnta ble 3/4' thick umc tcr brass or steelwood ba se s p ind le s ho u ld be

r;;;;;;;~;;~;;;;;;;;~ / Iappe d inlo a hoi c".c:i4~"J1);;H !.w 'I W(~~~ I~~Si;(~~~~en~~r~r~:~

/ca re must be taken whe n drill-

ing the hole to en sure tha t thespind le is true vertical.

Th e turn table tit s over the spindlewit h its und er rim resti ng and rotat ing on thewood surface. The sp ind le should be cut sothat it is fl ush with the turntab le upper surface.The baseboard top should be stained and po l-ished with a silicone wax po lish to aid insmooth turnta ble rotation. The frame or ferri teloop stands on the turntable top, and is ea silyrotatable.

Note; So me plastic turntables have a centerhu b protruding below the under edge of thetur ntab le.Thi s excess protuberance can be cuthack as requi red . using a short length of ahacksaw blade.

SIDE VIEW

I

Ell

-.-,4x rubber feet

Wood Base.I 3/4" min. thickness. I

""-Circular Rim

FIGURE 2

FIGURE 3

MetalsPindl:....~

-


~

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,

'"Twist wires toqether and solderFor this art icle the we will conce ntrate 0 11

the most popula r hands in thi s co untry: the 2meter band ( 144 MH zto 148 MHz) and the 70em ban d (4-tOl\.1Hz to '+50~'I I{ l ) . Ihave foundthe antenna to have a vo ltag e standing \\

.-.

may have lying aro und or buy u new piece 6foo l long.

You will need the following:

6 feel of fla t 300 ohm twi nlead6 feel or more of RG-58 coaxPL-259 or BNC connector (your choice)Soldering Iron and SolderWire CUllers. strip pers Of knifePlast ic e lec trical tape or heat shrink tubing

Buil ding the Antenna

Begin hy carefully removing 0.75 inch ofinsu lation from one end of the twinlead . beingcareful that you also do notcut the wires. Oncethe wire has been stripped. (wist the pa ir ofwire s toget her and ..older. Thi s is the bot tomof the antenna.

C ur the twi nlcad 10 54 inches ex actly fromtop to bottom. Do uble check the length : itneed s III he ex act.

Measure 1..25 inches up from the bottomofthe antenna and mark the insulation. From thisma rk. care fully 1'1:1110\'\: the insulation for .25

inches above and be low the mar k, bei ng ca re-fu l not 10 nick the wire . Repeat on the otherside of the twin lead .

Measure exactly 15.25 inches from the oneof the notches yo u ha ve j us t cut and remove a.25 inch notch from (his po int; remove boththe insulation and the wire . This is the grou ndsidc ( 1/4 wave stub). The other uncu t side isthe radiator side (3/4 wa ve) of the antenna .

Us ing a pie ce of RG -5Hcoax at least 6 fee tlong, carefully rem ove .75 inches of insula-tion from the coax to expose the braid. Sepa-rate the brai d from the ce nter conductor andtwi st toge ther, Remove the insulat ion fromthe center co nduc tor. Connect the braid fromthe coax to the ground side (s tub) of thetwinlcud and the center co nductor to the longside {radiator) of the tw inlead . T ry to co nnec tthe coax so tluu it lays in the cente r of thetwlnlcud. So lde r the CO

-.

-_.I

cAR DXINGI

How you can escape interference at homeand go on a DXpedition every day

By Hans Johnson

Everything is there: power, and antenna, and a tape recorder. Y OUT shack 011 wheels isready 10 go.

YOU have finally escaped that QRM(manmade interference) at home andgone onyour DXpedition insearch ofdistan t signals. The logbook is soon filledwith all sorts of new stat ions. bUI sadly. it hasto come to an end after a few days.

How ca n on e recreate those DXpcditionconditi ons eve ry day?

Car DXing is the answer.

C ar DXing. also Known as a micro-DXpedi tion. is a sing le listening session fromyour ca r. Mos t of my listening in the last threeyear s has been while Ca r DXing. so let meshare with you some of what I learned alongthe way.

Location, location , locat ion

One of the keys to hea ring rare stations is to

try for them often. Car DXing must be as easyand convenient as possible, otherwise youaren 't going to go very often because it is toomuch trouble.

T he most importa nt aspect of Car DX ingis the location you choose, The idea is toimprove upon the conditions you have athome. This is done primarily by finding alocation with space for a bette r antenna, q ui-

c tcr conditions, or a combination of' thetwo. Rememb er. if it isn' t easy. youaren't going to do it. A good site fiveminutes fromthe house is better than anexcellent one an hou r aw ay.

A few words of caution. Don ' t CarDX d ose to houses where it mightmake the locals nervous. Secondly,don' t Car DX from office parking lotsor anywhere that is posted. Finally.choose parks with care. avoiding theones that are rather fes tive in the eve-nings. (Yes, I have learned all this thehard way.)

There are plent y of goo d spots closeto where yo u live; you simply havc 10seo ul aro und and be wi lling to try themout. Apartme nt dwellers. try DXi ngfro m your car right on the apartmentgrou nds. It certainly will be qui eterthan inside the apartment and you mightjust find plenty of roo m for so me tem-porary antennas.

Parks ca n begood, too . DXing fromsmall. neighborh ood parks will prob-ably be an im provement on your con di-tions at home. One of the first thin gs I


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Dealing with ron Signalsrhe Receiving Antenna runer

ByA.W. Edwards

ing to accept one freq uency better than all therest.

Figure I shows two bas il' L-C reso nantcir cui ts: parallel and series. The parallel re-o-

c

L

L

nant ci rcuit is a lso called "anti -resonant" be-cause it offe rs a very high impe da nce (rejects)the resonant frequency. but a llows other frc-qucncics to pass throug h. By co ntras t, theseries resonant ci rcuit does j ust the opposite .o ffer ing a very low imped ance 10 (accepts) thetuned frequency wh ile rejecting all othe rs.

cFIGURE 1

A parallel-resonantcircuit rej ects the tunedfre quency but allowsothers to pass through.

Th e current GTlH'e.HiIJ TuIJ er is th eTUN-.JA, all updateof tile TV ,V3mentioned by th eauthor.

,t series-resonantcircuit accepts thetuned frequ en cy andreje cts all others.

FIGURE 2

Two Ways to Work MagicNOW thai I am retired I have beengo ing ove r sonic old no tebookscbcmurics. ideas. and looking

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I bought the Grove Mini'I'uncr (TUN-.3 l atleast len years ago . It is a compact . well-designed unit. It is surprising 10 note howmuch performanceand whit! a broadcoveragerange is packaged ill tharli ulc box. Ihave builldevi ces before and since I bou ght if. for spe-c ialized purposes. Wit h 1I0 W mort: than twodecades of hands-on experie nce. I am stillsuffic iently impressed hy the simple series-resonant LC circuit to want to write abou t it.

11 is a given that almost any passive itemone inserts in a fecdlin c might he ex pected 10degrade the input sig ll.1I 10 some extent. ifonly slightly, Even band-ne w coax has its "d l!loss per hu ndred feet" ligu res published. ( Itwould hewo nderful if the oppos ite were true:3 dB GAIN per hundred feet at all frequen-cie s. Inr cxumpl c. But life j ust ain 't that way.I

Or is il '! Anything we put into the tra nsmi s-sion line for transmitters will present so me" inserti on loss:' he iL

FIGURE 3Circuit used 0 11ship to protect receivers fromdamage fromhigh power RFfields (see text}.

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in the presence of strong RF fie lds the diodescond ucted . placin g one end of the filament toground.

If the coupled energy were excess ive itac ted as fuse. opening the antenna circuit andprotect ing the receiver input. This necess i-tated repl acement of the lamp. but it wasmuch preferable to having irrepl aceable com-ponents dam aged .

A word about the diod es: Use co mmondiodes such as the IN400 I. orothers with 500rna. to I ampere rating at 50-2 00 p.i.v. Do notuse sens itive RF signal diodes; we don' t wa ntsigna l detec tion at this po int. and they arc notrugged enuugh.

Th e circuit worked so well tha t I was askedto make and insta ll them for the captain andother shipmates. One time while coming intoa port I notic ed the lamp was flicke ring . Thecause turned out to bean AM broadcast tran s-mitter about a mile distant! So it sure 'nuffwor ks .

ANT.TERMI NAL

RECEIVER

SEE TEXT

Other Tuning Tricks

Here arc some other tips that are usefu l forgenera l SWLing at any frequ ency. One trick Iha ve found 10 be qui te cffective when trying toreceive an AM shortwave broadcast throughadjacent channe l interference is 10 usc theupper or lower side band (US B or LSB ) func-tion s. Ofte n by choo sing one or the otherside band and zero-beating the de sired signal.rem arkable improvement in iso lation and clar-ity results.

T he nulling fea ture o f a homemade wiredloop or a ferri te stick can also produce exce l-lent rejection res ults if the dir ect ion of arriv alof the competing signals is more than a fewdeg rees differen t. Co mmercially availab leloop s call e liminate or greatly redu ce unde s-ired signals on the sa me frequ ency by nullin gout or greatly redu cing the strength of theoffending signa l. Also . the judiciou s adju st-ment or RF gain (or an uttenu ator} ca n pro-duce im pro vement.

series tuning capaci tor for "fine tunin g." whichmade it a series reso nant device .

P/otection from Too Much Signal

Whil e u seago'ing Radio Officer I wasobliged 10 protect the sens itive inputs on mypersonal radio fro m very strong radio ener-gies (RF) from the ship' s several tra nsmitters.Once I neglected 10 disconnect the antennafrom my receiver . and the powerful RF fieldliterally cha rred so me fro nt end compo nents.To prevent ", recurrence of this disaster Idcsign ed a prot ect ive ci rcu it which workedexcellently.

Ahead of the antenna inpu t of the rece ive rI put in a circuit with ;'1 flO-mi lliampere pilotlamp (type 49 , pink head ). and back-to-buckdiodes. It d id not affec t normal inco mingsignals (the lamp' s co ld res istance is low) but

TYPE 49(PINK BEAD)

ANTENN A

There arc good uses for bo th circuits.The series-resonant filter ' s ac tion rel ieves

the receiver input of the "d e- to-light" stam-ped e of electromagnetic signals presented bythe antenna. Instead of "s eeing" all the radiosignals and other electromagnetic emissionsimpinging on the antenna. now only a narrowpassband of signals eme rges from the tunerand is offered for recei ver processing. Th is isthe equivalent of eliminating eight lanes ofrush hour traffic from the highway, leavingon ly the much reduced traffic'o f the car poollane.

The wide spectrum of signals and noisespresent withou t [he filterin g act ion of a simpletuner adver sely affect receiver perfo rma nce:e ither the automatic gain co ntrol mutes de-sired signals along with the interference . or .with out it. 10 0 much gain swamps the frontend tuned ci rcuits 10 prod uce images and otherspurious responses.

In one memorable instance I had bee n besetwith noises that ob scured rece ption on themarine and aircraft beacon and communica -tion s band between 200 and 520 kHz. Th erewas a multitude o f screeching-so bowltngs. andrough signals that ripsawed across the weak ersignals of interest.

1 built a circuit of ten inductances. eac hwith a by pass switch, These cou ld be selec-tively inserted and summed with others. It wasplaced between the antenna and the receiverinput, By experimenti ng with co mb inations ofinductance only. I found se ttings that gave"clear channe l" recepti on of an othe rwisesmothered signal.

It was tru ly amazin g to sec the "in" and"out" comparisons: The difference went liter-a lly from no discern able signal to only thedes ired signal. A rad io ham friend of minecould not believe I was accomplishing thiswit h inductance switching until I ope ned thebox and showed him. I ult imatel y add ed a

Apri/ 1998 MONITORING TIMES 25

Richard BarnettScanMo#er@ool. rom

The World Above 30 MHz-~--------

Why We Do What We Do

More great volunteers' equipmen t,

Every now and then you run into someone in theconsumer electro nics indu stry who asks. " Whywo uld anyone wa nt 10 own a scanner?" These arcpeople in the busine ss of se lling the pro duct and yet theycan' t understand why any one wou ld wa nt to own, op er-ate, listen 10. or even look at a scanner. "What's thepurpose of it: ' they ask incredulously. "why do you needto knowwhat the policeare doingT'These people sec thatthe product is selling.so they accede to customerdemandand continue to stoc k scanners; ye t, they can ' I understandwhy the custo mers want them.

While there is a level of ignor ance in some circles o fthe business (as there certainly has been in the federalgo vernment ), there are many others, grate fully, whoapprec iate the value o f the sca nncr. We did ge t tothinking recently though about why we do scan. What isit that captures our inte rest? What is it that keep s uscoming back to that volume and that squelch knob , thatsca n and manual key, when we could just as easily hit theup arrow on the remote control and selec t a boob tubechannel to keep us hypnoticall y transfixed?

Setting aside the Letterman-like humor, here is myTop 10 list of reasons why we sca n, I wo uld appr eciate hear ing yo urthought s on this matter as wel l. Perhaps we need to have a pam phletat the ready, or at least a ready list of answers, for those industry (orcongressional) suits who qu estion ou r hobby and, for many, ourpro fession.

10. \Ve scan because we're fascinated by co mmunica tions. We'refascinated by radio tec hnology, the challe nge of findin g newfrequencies, piecing together radio sys tems , and understandingthe intri cacie s of ho w it all wor ks. ~

9. We' re co nce rned ahout our ow n, and our neighbo r' s. safety.We're members of cr ime watch gro ups and theres value inlearning abo ut crime in our area.

8. We're in the two- way business and scanners help us dete rmineavailable frequencies, tone codes. and other information that'simportant to our business.

7. We 're ra il-fans or air-fans who don 't rea lly ca re about scann ingpe r se, but by scanning we can lea rn more abo ut and bett er enjoyour primary hobby.

6. We ' re truckers and we wa nt to keep up -to-date on road co nditionsand po lice activ ity.

5. We' re firefi gh ters who need to know what' s happenin g. in ourcommunity while of f-duty or on-call.

4. We ' re news photographers and reporters who arc responsible foruncovering the stories that are reporte d on TV , radi o, and in thepapers.

3. We want to know where that po lice car, fire truck or ambulanceis goi ng that j ust passed our house and why it' s go ing there.

2. w e' re auto racin g fans who like to listen to the drivers talk to thepit c rews.

I. We like to hear the news as it happens.

If yo u lake all the above reasons and boi l them down : we j ust wantto know what's going on around us. We 're taking a pro ac tiveapproach in learn ing of this information pract ically firsthand. We 're110t waiting for the T V news or for the paper the nex t day . We' recurious, sure, but that ' s only hum an natu re. Businesses have do nequ ite well appeal ing 10 human natu re.

T his then begs the question about how we firs t beca me inte restedin scanning. Was it through watching T V sho ws such as Eme rgencyor Cops? Was it by see ing a scanne r at a nclghbor' xhou se? This is nottrivia l curiosity : To encourage the industry to give mo re crede nce tosca nners, develop new mod els, and adve rtise them as we ll, it' sirnportnnt tn he able to present a cogent argu ment as to not on ly whywe sca n, bUI how business ca n entice tha t potent ial first-time scannerbuyer to actually plunk down the S 100-plus doll ars to scan.

Scanners fi rst gained immense popularit y dur ing the race riots ofthe late 1960s. With Vietnam war-prote sts. racial and other civil strifein the country , many people were holed lip in the ir hom es, fearful fortheir lives. News organiza tions were not as ubiquitous as they aretoday. T here was 110 C NN News or local new s live all day long.People were unsure what actually was happening down the block orthe next neighborhood over. The scanner fi lled that void.

Today, with the im mediacy of news on TV, cuhlc . satellite, andthe Intern e t. you could make the argum ent that there is less need to usc

26 MONITORING TIMES Apri//998

a scanner 10 lea rn what is happen ing ou ts ide the wa lls of one s horne .We' re thankfu l. 10 0 , that ther e is no widespread ci vi l strife in thenation as there W

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Stuart is not licen sed on a trunked sys tem- they are e ithe r on theirVHF/U HF cha nne ls or 011 Mart in Cou nty' s sy stem.

The nearest Publ ic Safety sys tem that would be truckablc with theTru nkTracker is West Palm Beach. hut thai is too far to be receiv edin Stuart. There arc . however. sev era l comme rcial trunked SMR's inthe are a. but I do not have any trunkin g info on them. oth er than thefact that Nex tel (w ho ow ns mo st of them ) will be shutt ing off allanalog systems February 28. Hope that helps!"

TrunkTracker TIps

Brian Cathcart, KE4PM J- alias 'The Scanner Dude," a southFlorida resid ent ex pert 0 11 sca nning ami trunktrac king- passed on thefollowing tip on the TrunkCom list server recently:

"At the recent Miami Hamfest a fellow TT user passed on a greatlip that ' s not in the manual (or at least no t the ma nual l have). To godirec tly toa stored TT 10 in me mory. pre ss the numbcr ofthc trunkingbank plus the number of the tm nking memory and press enter, and theIT will go directly 10 tha t memory ! Thus. to go to ID memory bank5. 10 channel 6. enter "S-6-ENTE R" and it' ll go directly there.Another example: I have Broward County Fire-Rescue "North"channel (8208 ) in bank 3. channel 6. I press 36 then ENTER. and itgoes d irectly there. You have to be in trunkin g mod e and tracking asys tem, and you have to be scanning or ho lding on one of the 10mem ories. In other wor ds, you ca nnot do this whil e in ID SRC Hmod e."

[Edi tor's Note: Brian left one important item ou t. You need 10 hitthe Manua l key fir st before hitting the bank and channe l numbers.]

Brian also ans we red a qu estion tha t wa s posed on Tru nkComabout communicatio ns in the Stua rt and Mar tin County, Florida , area .

"Mart in County is on a 14-chan nel EF Johnso n analog sys tem.Po lice. fire , and local government is usin g it. except the units inIndia ntown who usc R67.0 125 PL 156.7 (NPSPAC T AC I ) forop erations. Also the fire de partment still uses the ir old VHF system.Trunked sys tem frequencies :

Th e first th ree ba nks arc o f maj or interest. so they are the first tobe programmed . Ot her listeners ma y have a different SCI of priorities.

"Mo nitors living ill a c ity like Chicago could use some thingsimilar. I wouldn ' t put a ll of the suburban and city fire freq uenc ies inthe same bank. however. Too much acti vity in a c ity like Chicago.

"The listen er should decid e what the prio rity of his listening is. Inthe above exa mple in my se tup. onl y ba nks I. 2. 3 and 16 are beingscanned 90 percent of the time, This is because on some frequenc ies,th ree depar tments arc using: one freq uency.

"Too man y frequenci es bein g scanned at the same time may resultin a very imp ortant dispatch being mis sed in a town of inte rest. If Iprogrammed al l the police into the fir st 5 cha nnels in han k 1, 1 wo uldbe listening to 15 depar tments be ing dispatched ! Experience andlistening priority is the deciding factor in how to program channelsand ban ks. I do n' t think fire and po lice de part ments should be mixedtogether. It is too di fficult for me to rem ember which frequency is inwhat bank . All I need to kno w is that local po lice is in bank I. and li redepa rtm ents arc in bank 2. and turn it on .

"Hope thi s gives others some thoughts o n how to 'cu stomize ' howtheywould like their scanners to perform, Keep up the good wo rk . I enjoyyour column every mo nth."Jerry Smithja rren.smi1"@ \\"Or/d lll' l. aa.lI'1Chicag o Area Radi o Moni toring Assoc. memberCA R1\'1 A Web site ...http://www.theramp.net/sh abec/carma.htm

This is the bonk for police depcrnneots that bo rder ou t hJrther from bonk1 frequencies. Ihese are usually towns tha Ia re the secon d o r more townsof interest away from my home .This is prcqrommed with local todical freq uen cies.Medical freq uencies (MED1, MED2... 15 4.3400, etc.].State Police.Trunked system in Na perville.CornEd e lectric company.Rood

04 April 1998

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Transcript of 04 April 1998