Ramsey Electronics FX-146, User Manual

Page 1: ...crystals to buy Perky 5 watt RF output Dual conversion sensitive receiver with crystal and ceramic IF filters PACKET ready Dedicated packet interface connector on back 12 Channels expandable to as man...

Page 2: ...FTR 146 for two meters The FX Transceiver design was developed in immediate response to those builders suggestions wish lists and inquiries This publication is dedicated with deep thanks to all those...

Page 3: ...8 FX 146 Circuit Overview 19 Quick Reference Programming Guide 28 FX 146 Programming Worksheet 30 Using Computer BASIC as a Programming Aid 32 How to Activate an Auxiliary non Standard Offset 35 Progr...

Page 4: ...band 144 to 148 MHz Proper licensing is required for MARS or CAP operations Amateur licensees are required by the FCC to maintain strict control over their equipment to prevent unlicensed operation e...

Page 5: ...mic on your average speaker mic you have just grounded the audio output of your transceiver If All Else Fails FX 146 5 SPECIFICATIONS FOR THE RAMSEY FX 146 General Frequency Range Any 20 MHz segment...

Page 6: ...gh that you ll take it easy learning as you build and then enjoy the reliability of your Ramsey FX Transceiver for a long time to come The style of our kit building directions presumes that you are pe...

Page 7: ...efer pin VDC pin VDC pin VDC pin VDC 20 0 0 16 0 0 12 5 0 24 0 5 19 5 5 15 0 0 11 5 5 22 0 0 18 5 5 14 0 5 10 0 5 21 0 0 17 0 5 13 5 0 25 0 5 23 0 0 VOLTAGES ON U6 146 52 MHZ IN RECEIVE TRANSMIT FX 14...

Page 8: ...at Ramsey have been speaking with customers making repairs experimenting and compiling notes on the FX 146 These notes and the circuit overview and theory of operation sections of your FX 146 manual...

Page 9: ...icensed RAMSEY ELECTRONICS INC FX 146 9 DC POWER SUPPLY CONSIDERATIONS Your Ramsey FM Transceiver is designed to operate from any stable DC voltage source in the 12 to 15 volt range from typical car b...

Page 10: ...ll need to make as attractive a finished unit as possible with a single trip to the neighborhood Radio Shack store FX 146 137 This completes the assembly of the low pass filter PC board Inspect the bo...

Page 11: ...s that the top black becomes the foundation for mounting the PC board with the standoffs as well as securing the SO 239 antenna connector assembly You may wish to repaint the white bottom which now be...

Page 12: ...annot be secured permanently to the bottom section until after installation of L9 R32 and L10 AFTER Alignment and before Transmitter tuneup 3 Install the strain relief grommet supplied with the transc...

Page 13: ...nd the leads trimmed away flush on the other side When soldering the disc caps be sure that their leads are properly soldered sometimes the body insulating material will coat FX 146 13 resoldered afte...

Page 14: ...sults discussed above there is no point in doing more work on the transmitter section until the problem is solved If you are not able to transmit at least within the same room and receive on any desir...

Page 15: ...ton pressed C81 is adjusted for exactly 146 52 MHz on your Ramsey frequency counter or a zero beat 146 52 MHz signal on a digitally accurate monitoring receiver If you cannot tune C81 low enough insta...

Page 16: ...in your antenna depends on your operating goals Regardless of the style of antenna it really pays to give serious attention to electrically solid weatherproof connections of the coaxial cable to the a...

Page 17: ...ng tools for installing SMT chip capacitor C75 Tweezers Magnifier if needed Low wattage clean soldering tip C75 Location of C75 FX 146 17 VHF PACKET DATA OPERATION Your FM transceiver was planned and...

Page 18: ...IF the case is properly soldered to the groundplane of the PC board as detailed in the assembly instructions The transistor is fully intended by the manufacturer to be heat sunk in this manner don t...

Page 19: ...networks at the respective IC s The full 12 15 volt input is supplied to the transmitter RF output section and to the audio amplifier U2 Components L20 and C42 provide ignition noise filtering The 5...

Page 20: ...ts need handmade preparation before installation in the transmitter RF stages of your transceiver We recommend that you get them ready for installation before wiring the Driver and Final stages If you...

Page 21: ...for a 2nd IF filtering scheme designed to solve the adjacent frequency swamping effect experienced with many handhelds costing much more The receiver has good hysteresis characteristics the ability to...

Page 22: ...acitance and thereby lowering the frequency Q5 is a common base buffer which affords good isolation low input impedance and broadband characteristics The buffered output from Q5 is fed into U3 TD6128...

Page 23: ...effect of the filter is that the beta of Q4 multiplies the 47 uf for a virtual capacitance effect of a much larger device Stage G The FX Transceiver Synthesizer PLL The MC145152 IC incorporates the e...

Page 24: ...peration and that receiver programming 21 4 MHz lower does not interfere with transmit operation A variety of techniques are possible for binary programming of U6 s 16 paralel inputs We focus on the d...

Page 25: ...fully on or fully off when the op amp outputs swing Releasing the mike button instantly reverses the status of Q12 Q13 and Q14 to return to receive mode R70 limits the current drawn by D17 to a safe...

Page 26: ...About 2 volts through R60 and R57 operate the microphone element which sends audio through C83 to U4A PNP transistor Q12 senses the tiny current draw of the microphone element and switches the 8 volt...

Page 27: ...or nearby hand held If desired a connection can be made to the wire sticking up from the PC board near C71 that wire will later be connected to the antenna jack You may then connect up to a signal ge...

Page 28: ...whatever point in the procedure that is most convenient for you Its purpose is to apply 5V to the desired diode bridge Connect the desired channel positions on the switch to corresponding matrix chan...

Page 29: ...r area You can change or delete any of these frequencies whenever you wish H44a Construct at least two diode bridges for frequency programming as illustrated H44b Install 2 or more diode bridges in th...

Page 30: ...0 1 0 1 1 145 07 29 014 1 1 0 0 0 0 0 0 0 1 145 09 29 018 1 1 0 0 1 0 0 1 1 1 145 55 29 110 0 1 1 0 1 1 0 1 1 0 146 52 S 29 304 1 0 0 1 1 1 1 0 0 0 FX 146 117 H41 Form one diode matrix bridge for the...

Page 31: ...100K resistors brown black yellow required for R91 R101 and R116 118 Plan careful soldering procedure and install the parts H22 40 a Install the 19 100K resistors brown black yellow required for R71 R...

Page 32: ...enience and is not integral to the Ramsey FX 146 operation If you have trouble running the program please get help from a local computer friend and not from the Ramsey factory we re radio guys not com...

Page 33: ...in those positions Let s work backwards starting with the actual diode positions and discover why they are put there Starting with the easiest add up the values for the 2 diodes used in the RPT line...

Page 34: ...r band edges for the 2 Meter band Notice that the values of the highest 6 positions are the same throughout the band We still must program in those six positions but we only need to calculate for the...

Page 35: ...X matrix row for the desired offset following our published instructions 3 Connect the channel row to the AUX matrix row by installing a diode as shown below The cathode end is soldered to the diode p...

Page 36: ...T all of the above bits 1 1 1 1 1 1 1 0 0 0 0 Then ADD 1 1 1 1 1 1 1 1 0 0 0 1 This is our two s complement value which we program into our offset matrix You ll see these diodes in the position for 60...

Page 37: ...IC program We recommend strongly that you fully understand how to make the attempted descending subtraction calculation yourself because that is your ONLY means for checking the accuracy of printed in...

Page 38: ...LLY CONTROLLED FX TRANSCEIVER FREQUENCY SWITCHING The 12 front panel switched channels with never a need for a crystal will cover most applications generously Yet many of us will want to figure out wa...

Page 39: ...10K G34 Install C85 1 uf marked 1 or 104 G35 Install diode D8 type 1N914 or 1N4148 Orient the banded cathode end correctly FX 146 39 4 DON T run switching cables across the VCO and Transmit RF side of...

Page 40: ...ircuit board BUFFER An electronic circuit stage a sort of referee that tells its input and output not to mess with each other Think about such a task It may also provide amplified output of the incomi...

Page 41: ...oldering as a single operation while others do better work with frequent breaks in the phases that involve repetition of steps The suggested order of assembly is for the benefit of the latter group If...

Page 42: ...eceiver whose output is mixed with another signal such as antenna input See SUPERHET LOCK The condition in a phased locked loop PLL in which all sections are working together as intended and designed...

Page 43: ...he next section We ll even see that the roles of the offset matrix and the binary adders U7 U10 are clear brief and simple to explain FX 146 43 magic number decimal to understand in FX binary frequenc...

Page 44: ...the PIN diodes used in the FX transceivers UNLOCK unlocked refers to the condition in a PLL phased locked loop where one or more elements of the loop become defective or incorrect preventing the phas...

Page 45: ...n the phase detector gets so unhappy that what is being fed into its two inputs is so far out of whack that it cannot make corrections If the loop is unlocked no useful control voltage reaches the VCO...

Page 46: ...the PLL Frequency Synthesizer and VCO will present the greatest challenge to understanding In fact these stages which are at the heart of the transceiver s design are not easy to explain in everyday...

Page 47: ...the end of most of the assembly stages Use these as a guide for tracing the circuit If you make the effort to understand each of the small sections of the big picture you should have no trouble in id...

Page 48: ...parts distributors or may be ordered through a Radio Shack store The following chart should help you make the most cost effective choice if replacement semiconductors are needed Part ID Type Recommend...

Page 49: ...be even easier after the PLL circuitry is completed When you are finished with this optional test disconnect DC voltage Then cut the wire to TP1 leaving 1 4 soldered in place to serve as a permanent...

Page 50: ...is temporary jumper applies 8V to all 8R points on the board You also have of course the option of wiring the microphone input and PTT circuitry before testing the receiver Even if you do not perform...

Page 51: ...pf disc capacitor marked 10 F9 C46 100 pf disc capacitor marked 100 or 101 F10 C50 100 pf disc capacitor marked 100 or 101 F11 C38 001 uf marked 001 or 102 F12 C57 001 uf marked 001 or 102 F13 Instal...

Page 52: ...coil is seated snugly on the PC board E2 Install C43 001 uf marked 001 or 102 E3 Install C54 56 pf disc capacitor marked 56 E4 Install C51 22 pf disc capacitor marked 22 E5 Install R30 51 ohm green br...

Page 53: ...equency in step with that variation If the frequency is varied in step with speech patterns or other audio signals such as tone shifts we are generating frequency modulation hence FM D5 and R31 perfor...

Page 54: ...ilarly if the oscillator output could reach Q9 and Q8 in the transmit section or even the transmit buffer Q10 some sort signal could be put on the air After the VCO is assembled on the PC board the in...

Page 55: ...3 L8 2 2 uH TX34 L9 VK200 RF choke TX49 Install AFTER alignment L10 04 uH TX47 Install AFTER alignment L11 33 uH mini TX7 L12 2 5 T TX40 L13 1 5T 5 16 dia TX28 L14 015 uH TX24 L15 2 5T 5 16 dia TX21 L...

Page 56: ...ire coil DR19 Install C28 47 pf marked 47 DR20 Install L2 another 015 uH small 2 turn wire coil DR21 Install L6 yet another 2 turn 015 uH coil DR22 Install C31 47 pf marked 47 DR23 Install C104 8 2 pf...

Page 57: ...stall D4 type 1N914 or 1N4148 Orient the cathode band correctly DR9 Install C53 01 uf disc capacitor marked 01 or 103 DR10 If you think that transistor Q3 type NE021 is tiny wait until you install C75...

Page 58: ...gh at a cost typically 20 to 25 We leave this option open to you The RF present now strongly favors signals that are in the desired frequency range of interest This RF is amplified again by Q2 and the...

Page 59: ...59 R71 100K H22 H40 U6 counter input pulldowns R72 R73 R74 R77 R78 R79 R80 R81 R82 R83 R84 R85 R86 R87 R88 R89 R90 10K G30 R91 100K H11 H21 U6 counter input pulldowns R92 R93 R94 R95 R96 R97 R98 R99 R...

Page 60: ...e needed Y1 21 855 MHz CR23 Receiver IF oscillator Y2 10 240 MHz G3 PLL reference oscillator Y CRYSTALS FX 146 87 FX SERIES TRANSCEIVER Simplified Receiver Block Diagram LOW PASS FILTER HIGH PASS FILT...

Page 61: ...uency selection TP1 F20 VCO control voltage TP2 F20 VCO output frequency TP3 F20 U3 prescaler output U1 MC13135 CR1 FM dual conversion receiver U2 LM380 B1 Receiver audio amplifier U3 MC12017 F21 Dual...

Page 62: ...ntil we have received the MINIMUM repair fee of 49 00 or authorization to charge it to your credit card account INCLUDE a description of the problem and legible return address Do not send a separate l...

Page 63: ...shielded coil marked LB53303HK Make sure it is seated squarely on the board before soldering Solder all pins CR24 Install C101 4 7 or 10 uf electrolytic observe polarity Install these following resis...

Page 64: ...ND FEATURES In addition to audio output at pin 17 a separate high speed data output up to 35000 baud is available and may be linked directly to a packet TNC or other data controller using the jumper w...

Page 65: ...e detector Inductor L1 is the quadrature coil requiring a simple one time adjustment The exact process of detecting intelligible FM voice or data from the 455 KHz 2nd IF is the job of the remaining se...

Page 66: ...ously required for a quality FM receiver circuit For years Ramsey Electronics has employed a similar IC the MC3359 as the heart of our popular FM receivers for the 10 6 2 and 1 25 Meter bands We adopt...

Page 67: ...to make L9 and L19 1 hookup wire as needed may include 1 2 or 3 conductors 3 wire cable ties 1 5 16 x18 bolt to wind coils on for perfect spacing 1 document packet including this manual REQUIRED NOT S...

Page 68: ...istors and miniature inductors used in this project require upright or vertical installation It is important to follow the orientation illustrated for vertically installed parts Always put the body of...

Page 69: ...es of box cartons Since the assembly of this kit is presented in distinct stages some builders may prefer to group their parts by stage before beginning assembly 11 HELPFUL HINT Many of the parts are...

Page 70: ...ew coils and RF chokes The piece of thin enameled magnet wire is to be wound on the small toroid coil in Assembly Stage CR TINNING is the process of heating the stripped end of a wire and LIGHTLY flow...

Page 71: ...se or just badly made power supplies Stage A of your FX Transceiver is designed to help your radio survive quite a wide variety of imperfections It s not a power supply in itself but it comes close be...

Page 72: ...and U4 and couples packet audio to the microphone input line A18a Select D9 one of the many 1N914 or 1N4148 switching diodes used in the circuit Don t confuse these diodes with the smaller PIN and va...

Page 73: ...73 Stage A ASSEMBLY STEPS A1 Strip 1 8 of insulation from the heavier gauge black wire insert and solder in the GROUND hole This connection may be soldered on the TOP side of the board as well as the...