PM-2458 Manual 900-000002
Contents
1. PRAYXSYM Power Meter PRACTICAL SYSTEMS ENGINEERING PM 2458 User s Manual ED sn omer ES yp PM 2458 Warranty concerns or claims should be pursued with the company from which the product was purchased PRAXSYM warrants that all items will be free from defects in material and workmanship under use as specified in this guide for a period of one year from date of delivery PRAXSYM further agrees to repair or replace at its discretion any failure which upon PRAXSYM s inspec tion appears to be a result of workmanship or material defect In no case shall PRAXSYM s liability for breach of warranty exceed the pur chase price of the items in question PRAXSYM s liability on any claim of any kind for any loss connected with or resulting from the use of performance or breach thereof installation inspection operation or use of any equipment furnished by PRAXSYM shall in no case exceed the purchase price of the goods which give rise to the claim Illustrations by Mike Gorman Prairie Wind Communications Inc Phone 303 470 6367 Email mgdcabler comcast net Copyright O 2004 Castle Rock Microwave LLC PRAXSYM TABLE OF CONTENTS Introduction to the PM 2458 1 Using the PM 2458 2 Measuring Transmitter Power 5 Measuring Transmission Line Loss 7 Measuring VSWR of Antenna and Terminations 9 Specifications 11 Appendix VSWR Table 13 Appendix Notes 15 Page ii PM 2458 Introduc2. 1 01 46 1 0 005 0 0002 1 02 40 1 0 01 0 0005 1 03 36 6 0 022 0 0011 1 04 34 1 0 04 0 0018 1 05 32 3 0 06 0 0028 1 06 30 7 0 082 0 0039 1 07 29 4 0 116 0 0051 1 08 28 3 0 144 0 0066 1 09 27 3 0 184 0 0083 1 1 26 4 0 228 0 01 1 11 25 6 0 276 0 0118 1 12 24 9 0 324 0 0139 1 13 24 3 0 375 0 016 1 14 23 7 0 426 0 0185 1 15 23 1 0 488 0 0205 1 16 22 6 0 55 0 0235 1 17 22 1 0 615 0 026 1 18 21 6 0 682 0 0285 1 19 21 2 0 75 0 0318 1 2 20 8 0 816 0 0353 1 21 20 4 0 9 0 0391 1 22 20 1 0 98 0 0426 1 23 19 7 1 08 0 0455 1 24 19 4 1 15 0 049 1 25 19 1 1 23 0 053 1 26 18 8 1 34 0 056 1 27 18 5 1 43 0 06 1 28 18 2 1 52 0 064 1 29 17 9 1 62 0 068 1 3 17 68 1 71 0 073 1 31 17 4 1 81 0 078 1 32 17 2 1 91 0 083 1 33 17 2 02 0 087 1 34 16 8 2 13 0 092 1 35 16 53 2 23 0 096 1 36 16 3 2 33 0 101 1 37 16 1 2 44 0 106 Page 13 PRAXSYM Return Loss Reflected Transmiss VSWR dB Power Loss dB 1 38 15 9 2 55 0 112 1 39 15 7 2 67 0 118 1 4 15 55 2 78 0 122 1 41 15 38 2 9 0 126 1 42 15 2 3 03 0 132 1 43 15 03 3 14 0 137 1 44 14 88 3 28 0 142 1 45 14 7 3 38 0 147 1 46 14 6 3 5 0 152 1 47 14 45 3 62 0 157 1 48 14 3 3 74 0 164 1 49 14 16 3 87 0 172 1 5 14 4 0 18 1 55 13 3 4 8 0 21 1 6 12 6 5 5 0 24 1 65 12 2 6 2 0 27 1 7 11 7 6 8 0 31 1 75 11 3 7 4 0 34 1 8 10 9 8 2 0 37 1 85 10 5 8 9 0 4 1 9 10 2 9 6 0 44 1 95 9 8 10 2 0 47 2 9 5 11 0 5 2 1 9 12 4 0 57 2 2 8 6 13 8 0 65 2 3 8 2 15 3 0 73 2 4 7 7 16 6 0 8 2 5 7
3. 3 18 0 88 2 6 7 19 5 0 95 2 7 6 7 20 8 1 03 2 8 6 5 22 3 1 1 2 9 6 2 23 7 1 17 3 6 24 9 1 25 3 5 5 1 31 1 61 4 4 4 36 1 93 3 9 2 27 3 5 2 56 PM 2458 Notes Page 15 PRAXSYM Notes Page 16 PRAXSYM 31110 RevA P N 900 000002 001
4. Con nect the meter as shown on the opposite page Take another for ward power reading Subtract this forward power reading from that taken directly off the back of the transmitter This is the amount of signal lost due to attenuation in the transmission line and termina tions This value can be compared to the loss specifications of the transmis sion line and connectors to verify that the coax is properly termi nated Page 7 PRAXSYM zer TRIOS IAN Page 8 PM 2458 Measuring VSWR of Antenna and Termina tions measure the VSWR of an antenna place the meter into the system between the transmission line and the antenna Use the FORWARD SIGNAL arrow on the meter to orient the meter properly The arrow will point towards the antenna when it is properly inserted The dou ble male type adapter can be used if the antenna has a female type connector Apply power to the transmitting device The meter will display the VSW R so long as there 15 power reaching it between 0 and 20 dBm In other words if the transmit power of the radio minus the transmission line loss is less than O dBm the meter will read Below Range Likewise if for some reason the power at the meter exceeds 20 dBm it will display Exceed Range The best return loss that the meter can read accurately in any of the bands is roughly 20 8 dB This correlates to a VSWR of roughly 1 2 1 Most antenna manufac
5. cal Specifications Frequency Range 2 4 2 4835 GHz 5 150 5 350 GHz 5 725 5 850 GHz Forward Power Measurement Range 0 dBm to 20 dBm no inline attenuation 10 dBm to 30 dBm 10 dB inline attenuator 20 dBm to 40 dBm 20 dB inline attenuator 30 dBm to 50 dBm 30 dB inline attenuator Reflected Power Measurement Range 20 dBm to 17 dBm no inline attenuation 10 dBm to 27 dBm 10 dB inline attenuator 0 to 37 dBm 20 dB inline attenuator 10 dBm to 47 dBm 30 dB inline attenuator Power Measurement Accuracy 0 5 dBm with a 1 2 1 LOAD Insertion Loss 0 4 dB 2 4 GHz 0 75 dB O 5 8 GHz VSWR Measurement Range 1 2 1 to 6 0 1 2 4 GHz 1 2 1 to 6 0 1 5 3 GHz 1 2 1 to 6 0 1 5 8 GHz Environmental Specifications Temperature Range 10 to 50 C Humidity 95 non condensing Altitude to 15 000 feet Mechanical Specifications RF Connectors Type female input output Display 2 lines by 8 characters LCD not illuminated Keypad Five keys see definition on page 3 Enclosure Black ABS Page 11 PRAXSYM Mechanical Specifications cont d Power Source 2 AA alkaline batteries industrial grade Size 4 9 x 2 7 inches exc N connector Weight 10 ounces Page 12 PM 2458 Appendix VSWR Table Return Loss Reflected Transmiss VSWR dB Power Loss dB 1 00 0 0
6. e a 50 Q load on its output when connected to a transmitter Depending on the type of test this can be an antenna or the 50 termination included in the kit The 20 dB attenuator is included for use when the device under test trans mits a signal higher than 20 dBm in amplitude When using the 10 dB attenuator it is a good idea to change the offset to 10 in the MODE settings page 4 Note that the input to the 2 W 10 dB attenuator should not exceed 33 dBm 2 W If an attenuator with a higher power rating is used the input into the attenuator can be increased such that the output of the attenuator does not exceed 20 dBm The attenuator offset should be set for 00 when no attenuator is used Page 2 PM 2458 The meter should always be inserted into the system in the forward power direction Use the arrow labeled FORWARD SIGNAL as a guide when connecting the meter Pressing and quickly releasing the ON OFF button turns the meter on The meter will display Below Range if it is not connected to a source that 15 within it s dynamic range 0 to 20 Once the meter is connected to a source and a 50 Q termination is placed on it s output the forward and reflected power can be meas ured If the meter is not properly terminated the forward power measurement may be inaccurate If the signal applied to the meter exceeds 20 dBm the meter will read Exceed Range VSW R is automatically calculated and display
7. ed according to the for ward and reflected measurements The accuracy of the VSWR meas urement depends on several variables forward and reflected power levels attenuation in the transmission line etc Button Description ON OFF Turns the unit ON or OFF Unit also powers down five minutes after last key depression Powers up to the last state that it was in SELECT Used with MODE key to make selections MODE First push Displays remaining battery life Second push Allows selection of the unit of power dBm or mW on the display Third push Allows selection of the freguency band of interest 2 4 5 3 or 5 8 GHz Fourth push Allows selection of the inline attenuator offset 0 dB 10 dB 20 dB or30 dB Fifth push Exits MODE and returns to selected moni toring state FW D or REFL Depressing FWD or REFL also exits MODE at any time FWD Displays forward power and VSWR A right pointing arrow in the upper right of the display indicates the meter is measuring forward power The power Page 3 PRAXSYM measurement is displayed continuously The VSW R is displayed for two seconds on the bottom display line and then is replaced for one second by the band indi cator 2 4G 5 3G or 5 8G and the in line attenu ator setting 00 10 20 or t30 REFL Similar in function to the FWD button except it dis plays the reflected power and shows a left pointing arrow in the upper right of t
8. he display Page 4 PM 2458 Measuring Transmitter Power The meter should be connected to the transmitter according to the FORWARD SIGNAL label on the meter see the illustration on the opposite page Depending on the gender of the type connector on the transmitter it may be necessary to use the double male type adapter The meter should be terminated with the 50 load in cluded in the kit Turn the PM 2458 on by pressing the ON OFF button Select the fre quency band of interest by pressing the MODE button until the fre list 15 shown Use the SELECT button to scroll through and select the appropriate band A small arrow should be displayed be side the band 2 4 5 3 or 5 8 Press the FWD button to read the forward power A small right pointing arrow will appear in the upper right side of the display This is the amplitude of the signal in or mW depending on the unit selected in the MODE menu in the forward direction The meter is designed to detect signals between 0 and 20dBm in the forward direction and 20 to 17 dBm in the reflected Damage can occur to the meter if the forward power into the meter without the attenuator exceeds 36 dBm Most broadband radio transmitters deliver less than 100 mW 20 dBm The 2 W 10 dB attenuator can be used for sources that are between 20 and 30 dBm in amplitude Remember to apply the ap propriate offset in the MODE setting 10 if the a
9. tion to the PM 2458 The PM 2458 is a handheld broadband power meter capable of de tecting forward and reflected power in a microwave radio system The meter is capable of detecting various types of wireless broad band modulation schemes in the license exempt 2 4 5 3 and 5 8 GHz frequency bands The meter was designed with the system integrator and installer in mind It is the perfect tool for the verification of transmitter power transmission line loss characteristics and antenna performance Key features of the PM 2458 e affordability e portability tri band use in the microwave bands 2 4 5 3 and 5 8 GHz e verification of system installation Gorman 2005 Page 1 PRAXSYM Using the PM 2458 The PM 2458 ships with a durable nylon case that is secured with hook and loop flaps The package is designed so that the meter can be used while still in the nylon case The flaps that cover and protect the meter can be secured behind the unit while it is in use This is shown on the front cover of this manual Packaged with the meter is male to male type adapter in the left pocket a 50 2 termination right pocket and a 2 W 10 dB attenu ator in the pocket above the meter Male to male adapter 2 W 10 dB attenuator Most transmitters have a female type N connector on them The double male adapter can be used to connect the meter directly to the transmitter The meter should always hav
10. ttenuator included in the kit is used If the output of the transmitter exceeds 33 dBm 2 W an attenuator of the appropriate power rating and insertion loss should be used to lower the signal to a level below 20 dBm Using the MODE button an offset can be configured for attenuators up to 30 dB If an attenuator is not used the offset should be set to 00 While the forward power is displayed constantly on the top line of the display the bottom line alternates between the VSWR and the frequency band and offset settings NOTE A good way to verify proper operation of the 50 Q termination included in the kit is to make sure that a VSWR of 1 3 1 is displayed when the meter is connected according to the diagram on the oppo site page If the VSWR is not 1 3 1 the termination should be placed Page 5 PRAXSYM LO o Page 6 PM 2458 Measuring Transmission Line Loss the forward power of the transmitter as shown on the previ ous pages Use the 50 termination included in the kit as the load Make note of the forward power reading Disconnect the meter from the transmitter NOTE The transmitter should always be powered down when there is no load present or when connecting the meter or transmission line Connect the trans mission line directly to the transmitter with the proper amount of attenuation if necessary Move the PM 2458 to the opposite end of the transmission line
11. turers in the license exempt broadband wire less market advertise a VSWR of 1 5 1 Therefore a defective or dam aged antenna feed should be pretty evident using the PM 2458 as they will indicate a VSWR higher than 1 5 1 It is possible to measure the VSW R or return loss of a transmission line termination by placing the meter between it and the radio It is necessary to properly terminate the far end termination with the 50 Q termination and typically a type N double female adapter not included These measurements are often only accurate for the local terminations or the terminations that are physically close to the me ter The two way transmission line loss may mask any reflections further down the transmission line or at the far end terminations i e make the VSWR look better than it really 15 The problem becomes more pronounced as the two way loss of the transmission line ap proaches the dynamic range of the meter which is 20 dB Therefore it is best to have as little transmission line loss as possible when at tempting to measure return loss or VSWR of a termination with the meter A VSW R vs return loss table is included in the Appendix NOTE Reflections are usually due to bad terminations kinks in the transmission line bend radii which are too tight or moisture in the line or connectors Return loss is simply the forward power minus the reflected power Page 9 PRAXSYM Page 10 PM 2458 Electri
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