Instruction/ maintenance manual of the product 21-533 Radio Shack
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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.
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 .
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.
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.
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.
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 .
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 .
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.
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 .
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.
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.
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) .
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 .
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.
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.
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.
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.
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.
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 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 .... .. .. ... .. .
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.
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 .
An important point after buying a device Radio Shack 21-533 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Radio Shack 21-533 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Radio Shack 21-533 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Radio Shack 21-533 you will learn all the available features of the product, as well as information on its operation. The information that you get Radio Shack 21-533 will certainly help you make a decision on the purchase.
If you already are a holder of Radio Shack 21-533, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Radio Shack 21-533.
However, one of the most important roles played by the user manual is to help in solving problems with Radio Shack 21-533. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Radio Shack 21-533 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
