Radio Shack 21-533 manuale d’uso

Ca t. No . 21- 53 3 OWNER’S MANUAL Pl ease read bef o re usi n g thi s eq ui pme nt. CB/Ham Fiel d-Streng th SW R Meter 21- 53 3. fm P age 1 T hur sd a y, Au gu st 5 , 19 99 3 :4 7 P M[...]

© 1998 Tan dy Corporation. All Rights Reserved. RadioSh ack is a registered trademark used by Tandy Corpor ation. 2 INT R OD UC TIO N Your Radi oShack CB/Ha m Field- Strengt h SWR Meter helps you tun e your CB or amate ur radio sy stem for the best per- formanc e. CB and amateur rad io syste ms work best when the ant enna syste m’s impeda nce ma[...]

3 CONTENTS Me asu rin g SW R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Connect ing the Meter . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Cal ib rat in g th e M ete r/M e as uri ng S WR . . . . . . . . . . . . . 5 Int er pre ti n g S WR R ead in gs . . . . . . . . . . . . . . . . . . . 8 Imp rov in g S W R . . . .[...]

4 MEASURING SWR Measuri ng SWR s hows y ou how m uch of you r radi o’s transm it power is reflect ed from t he antenna back int o the ant enna ca- ble, genera ting heat and was ting powe r. With thi s i nformat io n, you can adju st the le ngth of your antenna or ante nna cable so your ant enna and r adio co mbina tion can pr oduce th e maxi - mu[...]

5 1. T ur n off your r adio. Then di sconnec t the a ntenna f rom the r adio and pl ug it into ANTENNA on the back of t he meter . 2. P lug the coaxi al cab le int o the r adio’s antenna j ack and into TRANSMITTER on the back of th e meter . CALIBRATING THE METER/ MEASURING SWR 1. S et CALIBRA T ION/FS/SWR on the front of the met er to CALIBR A T[...]

6 mit on s everal channel s, choo se a fr equency in the middl e of the range of channels you use. (For exampl e, if you transm it on all 40 CB channel s, choose Chan nel 20, be caus e it is midway betwee n Channe l 1 and Channel 40.) • If you use a CB that has sideba nd modes (SSB), do not select any of t hese modes. (Use onl y AM for SW R measu[...]

7 5. P ress the tran smit key ag ain, th en read the SWR by not - ing the n eedle’ s pos iti on on t he upper SWR s cale. A meter readi ng of 1 on t he upper scal e is ideal . The f igure s hown between the upper and lower scale s on the met er (% REF POWER) indicat es the per centage o f power that is wasted th rough refl ectio n of the signa l [...]

8 Interpreting SWR Readings An ideal SW R rea ding i s 1.0, but this r ead ing is usual l y possi - ble o nly un der labor atory c onditions or wit h a dummy load. Ac- tual ant enna instal lati ons have hi gher readings . The in- format ion be low will hel p you interpr et th e read ings y ou get . SWR Effici ency Interp retation 1.0 t o 1.5 Excel [...]

9 IMPROVING SWR There are se ver al ways to imp rove t he SWR of y our ra dio/an - tenn a combinati on. Try these first. • B e sure you are using the type of cable re commended fo r your equ ipment. I f the manufact urer recom mends a 50 - ohm ca ble, do not substi tut e an other type that h as a di f- fer ent i mpedance. • Co nfirm that you mo[...]

10 MEASURIN G FIELD STRENG TH Your meter can meas ure the l ow level s of radi o freq uency (RF) generat ed by a radio t rans mitte r. You can use these m easur e- ments to map th e transmit ting di rect ion and co verage pa ttern of your anten na, or to compa re your r adio an d antenn a’s ef fi- ciency before and a fter an adjus tment . You do [...]

11 PREPARING THE ANTENNA SITE B efore yo u use the m eter to measure f ield str ength, you shoul d mark t he si te aroun d the antenn a in a patt ern that will hel p you mak e the measu remen t. A n easy way to d o this is t o map the a rea around yo ur a ntenna usi ng a templat e li ke thi s one. Antenna L ocatio n 21-5 33 .f m Pag e 11 Thurs da y[...]

12 The templ ate shows an imaginar y cir cle aro und an anten na. The spokes on the tem plate repr esent i maginary straight lines measured f rom the cent er of the circ le to 36 point s spaced equall y a rou nd t he ci rcle. Eac h str aight line i s 25 fe et in l ength. The num bers on the t emplate (1– 5 ) are a gu ide to sho w you where to mar[...]

13 For exampl e, for a 50-f oot diamet er ci rcle : 50 feet = 4.363 Feet 11 . 4 6 So, y ou wou ld place a mark ev ery 4. 363 feet ( 4 feet , 3 i nches) . CALIBRATING THE METER/ MEASURING FIELD STRENGTH Im portant : Be sure to fol l ow any radi o servi ce re gulation s tha t li mit the amount of time you can tr ansmit witho ut a break or sta- ti on [...]

14 2. Set CALIBRA TION/F S /SWR to CALIB R A TION/FS . 3. T o calibr ate the meter , have yo ur helpe r select a channel or fre quency on your transmi tter and hol d down its t rans- mit key . T ell the hel per not to s peak i nto t he m icrophone. Then, wh ile the hel per h olds do wn the transmi t key , wa lk around i nside t he marks you made us[...]

15 • If you hav e an amateur ra dio, se lect the c ont inu ous wave (CW ) or t uni ng mode to check the field str ength. 4. T o measu re fiel d stren gth, a s the hel per co ntinue s to hold down th e transmi t key , move t o the marke d spot on t he cir cle due n orth of the antenna, then wat ch the meter’ s needl e. Note t he readi ng on t he[...]

16 5. Move to each marked spot al ong the ci rcular path then repeat Step 4 for ea ch one, takin g anothe r readi ng and record ing that readi ng on t he templat e. Here is an exampl e of a co mpleted t emplate . It shows an an- tenna mount ed on the rea r bumper of an automo bile that is parked f acing n orth. The fi eld streng th readi ngs fo rm [...]

17 USING FIELD STRENGTH READING S TO T UNE Y OUR RADIO AND ANTENN A You can u se field str ength meas ureme nts to monit or th e ef f ec- ti veness of changes you make to y our radio and ant enna while you ma ke the m. Changes you might mak e inc lude: • Instal l ing a new antenna or anten na cable • Adjusti ng th e leng th of an an tenna • C[...]

18 Then, wh ile the hel per h olds do wn the transmi t key , wa lk around and adjust the met er ’s knob un t il the met er ’s nee- dle mov es to 3 on th e FIELD STRENGTH scal e. Notes: • If you use a CB that has sideba nd modes (SSB), do not select any of t hese modes. ( Use on ly AM for fi eld stren gth measu rem en t s). • If you have an [...]

19 CARE AND MAINTENANCE Y our RadioShack CB/Ham F ield-Streng t h SWR Met er is an exam ple of super i or design and c raftsmanshi p. The fo llowing sugges t ions will help you c are f or your meter so you ca n en- joy it for y ear s . Ke ep th e m e ter dr y. If it g et s we t, w ip e it d ry im- mediat ely. Liqu i ds can con tain mineral s that c[...]

20 Modifyi ng or tamperi ng wit h your meter’ s in ternal co m po- nents can cause a mal funct ion and might inval idate the meter’ s warra nty and void you r FCC aut horiza tion to o per a te it. If you r me ter is not opera t ing as it shoul d, take it t o your l o- cal Ra dioShack stor e for assi stance . 21-5 33.fm Pag e 20 Thurs da y, Augu[...]

21 SCHEMATIC D IAGRAM (illus - show s che matic diagram of met er) 21-5 33.fm Pag e 21 Thurs da y, Augu st 5, 19 99 3:4 7 P M[...]

22 SPECIFICA TIONS Measurabl e RF Po wer ....... ..... ..... ....... ..... ..... ... 1–1000 W atts SW R . ... .. ..... ... .. .. ... .. ... ..... .. .. ... .. ... ..... .. .. ... .. ... .. ..... ... .. .. ... .. . 1 –3 Impedance .... .. .. ... .. .. ... .. . . ... .. . .... . ..... ...... ... .. ..... ... .. . .. 50 Ohms Frequenc y Ra nge .....[...]

23 Limited Ni nety -Day W ar ranty This pr oduct is war ranted by Ra dioShack agai nst ma nufactur ing de fect s in ma- terial and wor km anship unde r normal use f or nin ety ( 90) day s from the date of purcha se from R adioShack com pany-ow ned stor es and auth oriz ed Ra- dioShack franc hi sees and deal ers. E XCEPT AS PROVIDE D HERE IN, Ra- di[...]

Ra dioS hack A Divisi o n of Tandy Corporation Fort Wo rth, Texas 7610 2 8110 81 26 0 A 3A8 Pr int ed in Ch in a (contin ued) This war rant y does not c over: (a ) dama g e or f ailur e caused b y or at- trib utable to acts of God, abus e, a ccident, m isuse , impr oper or a bnormal us a g e, failu re to follow instruct ions, imprope r installation[...]