Ramsey Electronics PM10DC, Manual

Page 1: ... microwatts to 50 Watts Auto scaling display shows forward power and reverse power in dBm watts peak power and average power Also displays percent of AM modulation 2x8 Line LCD display shows measurements on a clear and easy to read display Runs from 7 15V AC or DC Use our AC 1 wall adapter Highly accurate 1dB from 2MHz to 450MHz Effective from 100kHz to 1GHz however refer to the sensitivity charts...

Page 2: ...RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscillator QRP Power Amplifiers RAMSEY MINI KITS Many other kits are available for hobby school Scouts and just plain FUN New kits are always under development Write or call for our free Ramsey catalog PM10DC DIRECTIONAL COUPLER POWER METER KIT MANUA...

Page 3: ...u Build 8 Parts List 12 Assembly Display 14 Assembly Main Board 16 Schematic Centerfold 18 Directional Coupler Assembly 22 Front and Main Board Mounting 26 Testing 27 Using the PM10DC 30 How to Tune an Antenna 31 33 Board Layouts Schematic 34 35 Troubleshooting 36 Sensitivity vs Frequency Chart 37 Pictures 38 Warranty 39 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR ...

Page 4: ...k the match of your antenna by looking at the VSWR reading as well as reflected power The less reflected power the more power being transmitted over the air Without this power meter you might simply have to go with your best guess Since this unit also contains a directional coupler you can not only measure forward power power which exits the generating device but you can also measure reverse power...

Page 5: ...een on port C is determined by the ratio of the number of windings shown here as 7 1 Power coming back flows from A to B which causes a small portion to be seen on D If there is equal power going in both the forward and reverse directions there should be less power at D and C The power is sampled on D and C and this is done with the AD8307 log detectors VSWR is calculated from the ratio of the pow...

Page 6: ...s of 100 dB results convert it to power add the power to a total sum then take the average of all of them and display it all within one second s time All this while maintaining math accuracy of 0 024dB So how is the math done you may ask Well there isn t enough room to go into detail but here are some basic formulas I used to get this to happen Since our A D converter is measuring at 27 5mV per dB...

Page 7: ...e dBm from the samples to watts each time sum the watts then take the average watts not dBm This slows things down a bit but at least the accuracy is there Luckily the processor is fast enough to average 100 samples before up dating the display giving you a pretty good idea of average power Another useful thing the PM10DC does is show percent of AM Since we can take more than 200 samples between s...

Page 8: ...top side of the board provided The top side is clearly marked with the word TOP you can t miss it When parts are installed each part is placed flat to the board and the leads are bent on the backside of the board to keep the part from falling out before soldering 1 The part is then soldered securely to the board 2 4 and the remaining lead length is clipped off 5 Notice how the solder joint looks o...

Page 9: ... 3 Orient it correctly follow the PC board drawing and the written directions for all parts especially when there s a right way and a wrong way to solder them in Diode bands electrolytic capacitor polarity transistor shapes dotted or notched ends of IC s and so forth 4 Solder all connections unless directed otherwise Use enough heat and solder flow for clean shiny completed connections Surface Mou...

Page 10: ...and to re heat the solder dab to melt it to the component connection Let the solder cool and let go with the tweezers Inspect orientation and make sure the part is square and oriented over the correct pads Also make sure a connection doesn t overlap or short across adjacent pads and the part is placed flat on the PC board Apply solder to the rest of the pads Apply a touch more solder to the initia...

Page 11: ...ugh said Let s get building You are going to want to use a VERY clean desk space to assemble the surface mount parts of your kit Drop a resistor into even the smallest amount of clutter and it will disappear like magic in fact you would swear a magician was hovering over your shoulder in some cases when part after part disappears There are probably enough parts hidden in the papers on my desk to h...

Page 12: ...wn black red R20 21 1 10K ohm potentiometer Orange top 103 R4 2 50K ohm potentiometer Orange top 503 R13 19 1 47K ohm resistor yellow violet orange R11 2 100K ohm resistors brown black yellow R14 18 2 1 0K ohm 1 resistors brown black black brown R1 3 1 2 0K ohm 1 resistor red black black brown R9 3 10 0K ohm 1 resistors brown black black red R2 5 6 1 13 0K ohm 1 resistor brown orange black red R7 ...

Page 13: ...n the 5 method would be Brown for 1 black for 0 orange for 3 places after the last defined digit and then gold to identify the part as a 5 component So 1 0 000 ohms 5 A 1 10 0K resistor needs to identify one more place of precision than a 5 resistor does so it includes an extra stripe In this case it would be brown for 1 black for 0 another black for another 0 red for two remaining zeros and a bro...

Page 14: ...ful not to install it on the wrong side The header will be installed on the back of the LCD display Soldering will all be done on the front of the display which is the side that displays things and we will be soldering the short ends on the display board Make sure all 14 pins are soldered well Hold the heat there for a bit with the soldering iron to make sure the solder has flowed down into the dr...

Page 15: ...ay be generating away from the rest of the circuitry 11 Install C7 a 0 01uF ceramic capacitor 12 Install S1 one of the momentary pushbutton switches Make sure it is flush and square to the board before soldering 13 Install S2 the other momentary pushbutton switch These two switches will be used to toggle through the various modes of your power meter 14 Install the display as shown Make sure the di...

Page 16: ...tor Marked 103 7 Install R5 a 10 0K ohm 1 resistor brown black black red 8 Install C5 a 10uF electrolytic capacitor Note that electrolytic capacitors are sensitive to polarity they are only properly installed in one direction The capacitors typically have a stripe indicating the negative side and we indicate the positive side on the board Make sure to mount the negative side of all electrolytic ca...

Page 17: ...his is the micro controller and therefore contains all of the intelligence of the kit Make sure pin 1 is aligned properly and that all 20 pins are lined up before seating the IC into place 28 Install C15 a 0 01uF ceramic capacitor Marked 103 29 Install VR1 the 78L05 voltage regulator This part has the job of making the supply voltage flat at 5 0V output with a number of varying inputs 30 Install C...

Page 18: ...PM10DC y18 ...

Page 19: ...PM10DC y19 ...

Page 20: ...36 Install R24 a 1K ohm SMT resistor Marked 102 37 Install R25 a 47K ohm SMT resistor Marked 473 38 Install C14 a 0 01uF ceramic SMT capacitor 39 Install R10 a 33 ohm SMT resistor Marked 330 40 Install R12 a 75 ohm SMT resistor Marked 750 41 Install R8 a 120 ohm SMT resistor Marked 121 42 Install C12 a 0 01uF ceramic SMT capacitor 43 Install U5 the other AD8307 IC Remember to only solder one pin a...

Page 21: ...about this stage it will prevent many headaches later Now is the time to check part orientation especially of the capacitors diodes and ICs Don t be totally disappointed if you find one has been installed backwards simply get them in right before applying power 55 Install S3 the DTDP power switch Make sure it is square and flush before soldering so that it will properly stick out of the hole provi...

Page 22: ...us wire 2 Using small needle nose pliers bend each wire using the pattern above Try to get the bend dimensions as close as possible and keep bends nice and square as possible and the wires nice and straight Use the pattern above for actual size Hold your wires up against this to verify dimensions 3 Cut off a 12 section of the thin magnet wire We will wind 6 turns of this wire through one outside s...

Page 23: ... other side s windings now if you wish It may look sloppy but it sure helps 7 Take the wires on one end of the binocular core and twist them to gether tightly We want this twist to apply some tension to the wires to hold windings in place Solder these two wires together You will find that if given enough heat the insulation will melt from the wires allowing for the solder to flow 8 Place one of th...

Page 24: ...wn from the back side of the board to pin the core down flat Solder the wires to hold the core in place 10 Solder the bus wires on the same end of the core as well 11 Bend the entire core up in the air on the end away from where you just soldered about 1 4 It makes the winding of the wires much easier 12 Tin the two remaining ends of the magnet wire back about 1 Remem ber that we told you to leave...

Page 25: ...wire exiting the other side Cross it over to its opposite side and solder with ample heat 14 Bend the core back down It will probably want to spring back up again but you will have to press down and solder at the same time to make sure the wire is tight to the board 15 Solder the bus wires down to the main board s provided pads using your tweezers or needle nose pliers to press down on the bus wir...

Page 26: ... Align the display board with the main board so that the connector s pins line up with the pads on both the top and bottom of the board 3 Solder a single lead and check for orientation The front panel should be mounted as close as possible to the main board We don t want the front panel to be too far away from the main board then the display would no longer fit into the case They should also be sq...

Page 27: ... but the offset can vary quite a bit from unit to unit To further complicate matters it is hard to get an accurate base line for noise to adjust to We don t really have the luxury in most cases to have an accurate signal source so we are going to have to give this a best guess cali bration Luckily without any strong fields like a nearby transmitter present the base line is easy to calibrate to Jus...

Page 28: ...tion you should only see a very tiny amount of reflected power typically a hundred times less than the forward power Note the reading of the forward power at this point and write it down We will be adjusting R13 to match this power after we swap connections Now swap the connections on the jacks connecting the signal source to RF out and no load or termination to RF in Adjust R13 so that reverse po...

Page 29: ...til R reads 0dBm 9 With the 50ohm termination removed but the signal generator still con nected the F and R readings should be very close to each other You may gently spread or move the magnet wire windings to tweak the read ings so they read exactly the same This optimizes the directivity of the PM10 and is essentially mirror imaging both sides of the core You may use hot glue or tape to hold the...

Page 30: ...ward and reverse power in auto scaling watts Automatically converts dBm readings to power for you Scaling is such pW Picowatts which is Watts 10 9 uW Microwatts which is Watts 10 6 mW Miliwatts which is Watts 10 3 and W Watts Mode 2 Prefixes F R Forward and reverse power in dBm Mode 3 Prefixes V d VSWR and difference in dB display V Indicates VSWR which is a ratio of forward to reverse power This ...

Page 31: ...lls you that you are heading in the right direction and you should start trimming your antenna Be careful though don t start cutting long pieces off the antenna stick with a quarter of an inch at a time When the VSWR reading starts to go back up or levels out stop trimming If the value went down you will have to find a permanent way of appending a length of durable wire to the end of your antenna ...

Page 32: ...in relation to a high power am plifier and 12 5 watts lost from power sent over the air will mean nothing to additional distance coverage Use caution however since some transmitters do not like this much reflected power and instability results causing spurious signals and other problems See your transmitter documentation for more in formation on antenna matching Note however that most people striv...

Page 33: ...1 6 12 6 5 5 0 24 1 15 23 1 0 488 0 0205 1 65 12 2 6 2 0 27 1 16 22 6 0 55 0 0235 1 7 11 7 6 8 0 31 1 17 22 1 0 615 0 026 1 75 11 3 7 4 0 34 1 18 21 6 0 682 0 0285 1 8 10 9 8 2 0 37 1 19 21 2 0 75 0 0318 1 85 10 5 8 9 0 4 1 2 20 8 0 816 0 0353 1 9 10 2 9 6 0 44 1 21 20 4 0 9 0 0391 1 95 9 8 10 2 0 47 1 22 20 1 0 98 0 0426 2 9 5 11 0 5 1 23 19 7 1 08 0 0455 2 1 9 12 4 0 57 1 24 19 4 1 15 0 049 2 2 ...

Page 34: ...PM10DC y34 MAIN AND DISPLAY BOARD LAYOUT ...

Page 35: ...PM10DC y35 PM50 MAIN AND DISPLAY SCHEMATIC ...

Page 36: ... jack is installed in the correct orientation The battery should read at least 8V when the power is off If power tests fine but still no display check the mounting between the main board and the display board You may have a short between one of the signal lines and data cannot get to the LCD controller Also check to make sure you installed the display in the correct orientation PROBLEM The display...

Page 37: ...PM10DC y37 FINAL ASSEMBLY PICTURES ...

Page 38: ...1 0 4 32 7 10MHz 32 7 0 4 32 3 25MHz 30 3 0 3 30 35MHz 28 6 0 1 28 5 50MHz 26 3 0 1 26 4 75MHz 23 1 0 6 23 7 100MHz 20 8 0 8 21 6 250MHz 11 4 3 6 15 350MHz 8 8 4 7 13 5 500MHz 10 3 3 13 3 750MHz 16 8 9 24 9 1GHz 22 3 22 2 44 5 Level set at 0dBm on HP 8647A 250kHz to 1000MHz signal generator Serial 3349A03018 Measurements on final board layout August 20 2001 Results may vary according to assembly o...

Page 39: ...much be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA If you believe we packed an incorrect part or omitted a part clearly indicated in your assembly manual as supplied with the basic kit by Ramsey please write or call us with information on the part you nee...

Page 40: ...ly and Instruction manual for RAMSEY MODEL NO PM10DC REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS12 Needle Nose Pliers Ramsey MPP4 or RTS05 Small Diagonal Cutters Ramsey RTS04 OR Technician s Tool Kit TK405 ADDITIONAL SUGGESTED ITEMS Holder for PC Board Parts Ramsey HH3 Desoldering Braid Ramsey RTS08 Digital Multimeter Ramsey M133 TOTAL SOLDER POINTS 310 ESTIMATED ...