Difference between pages "RF-Amp" and "A Termination Insensitive Amplifier for Bidirectional Transceivers"

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[[File:RF-Amp_Front.png]]
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[[file:W7ZOI_TIA_3D.png]]
  
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== RF Amplifier Features ==
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== W7ZOI Design ==
  
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* From [https://zl2ctm.blogspot.com/2020/11/go-qrp-portable-ssb-rig.html Charlie Morris' (ZL2CTM) Go QRP Portable SSB Rig]
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* Paper - [http://w7zoi.net/bidirectional_matched_amplifier.pdf A Termination Insensitive Amplifier for Bidirectional Transceivers] - W7ZOI (Wes Hayward) design
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** Solid State Design for the Radio Amateur?
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* [http://w7zoi.net/transistor_models_and_the_fba.pdf Transistor Models and the Feedback Amplifier]
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* +22 dB gain
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* Termination Insensitive - input impedance that does not depend upon the output load
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* Input connectors: SMA or BNC
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* Bi-directional - amplifiers in both directions
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* 49x49mm card
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* 50 ohms in/out
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* 4x 4-40 mounting holes
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* BNC or SMA Connectors
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* Transformer-less
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* Power applied to one half at a time - determines signal flow direction
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* ~30 mA per side
  
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== RF Amplifier Design ==
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=== W7ZOI Schematic ===
  
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=== Schematic ===
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[[FILE:W7ZOI_SCHEMATIC.PNG]]
  
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[[file:RF_Amp_Schematic-4.PNG]]
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=== * Use ===
  
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== LT Spice Simulation ==
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* Between RF/LO mixer (IF output/input) and crystal filter
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* Between Crystal Filter and Product Detector / Balanced Modulator
  
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* [https://github.com/land-boards/lb-boards/blob/master/HamRadio/RF-Amp/LTSpice/2n3904%20amp.asc LTspice Simulation] - GitHub source file
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[[file:FARHADPNG.PNG]]
  
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=== Transformers ===
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== Schematic in KiCAD ==
  
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[[File:RF-AMP-LTSPICE_XFMRS.PNG]]
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* Single channel
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* With SPICE directives
  
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== Charlie Morris Design ==
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[[file:W7ZOI_SCHEMATIC_KiCAD.PNG]]
  
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* From Charlie's notes with mods for my use
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* Both channels
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** [https://zl2ctm.blogspot.com/2020/11/go-qrp-portable-ssb-rig.html Charlie Morris' (ZL2CTM) Go QRP Portable SSB Rig]
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* With SPICE directives
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* [https://www.mouser.com/datasheet/2/308/1/2N3903_D-2310199.pdf 2N3904 data sheet]
 
  
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=== Beta DC ===
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[[file:W7ZOI_SCHEMATIC_KiCAD-2.PNG]]
  
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* Geometric mean min/max beta at operating current
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== NGSPICE Simulation ==
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** =sqrt(100*300) = 173
 
  
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=== Beta AC ===
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* NGSPICE run from KiCAD
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** [http://ngspice.sourceforge.net/ngspice-eeschema.html Tutorial: ngspice simulation in KiCad/Eeschema]
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* +24 dB @12V
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* 2N3904 Alternate Node Sequence (MMBT3903 - SOT23)
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** KiCAD order 1 2 3 is the SPICE normal order
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** NGSPICE order: 3 1 2
  
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* Gain bandwidth product divided by operating frequency
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[[file:W7ZOI_Simulation_KiCAD-3.PNG]]
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** Assume operating frequency of 10 MHz (my IF is actually at 9 MHz)
 
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** = 300/10 = 30
 
  
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=== DC Operating Point ===
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* Closely matches
  
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* CE current 10 mA
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[[file:W7ZOI_Gainz.PNG]]
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** If Vce = 6V, this is 60 mW power dissipation
 
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* Assume Ve (voltage across emitter resistor) = 1/10 Vcc = 12V/10 = 1.2V
 
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*** R3 is Re (emitter resistor) = 1.2V/0.01A = 120 ohms
 
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* VCE = 0.7V (typical from data sheet)
 
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* V(emitter) = 1.2V
 
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* V(base) = V(emitter) + VCE = 1.9V
 
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* Assume current in biasing resistors = 10x current needed by DC beta
 
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** 10 mA in C-E, beta DC less = 10 mA/173 = 48 uA
 
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** 10x the current in the biasing resistors = 480 uA (calculated)
 
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* R2 is 1.9V at 480 uA = 3.9K use 3.3K
 
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** Actual current will be 1.9V/3.3 ohms = 634 mA
 
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* R1 sources current to R2 and transistor base
 
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** Voltage = Vcc (12V) - 1.9V = 10.1V
 
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** Current = 576 uA + 57 uA = 634 uA
 
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** R1 = 10.1 / .634 mA = 15.9K, use 15k
 
  
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=== Input resistance ===
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* Across Band
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[[file:W7ZOI_Simulation_KiCAD_S2.PNG]]
  
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* Parallel resistors R1, R2 paralleled with transistor input impedance
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== CAD ==
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** R1=15K, R2=3.3K
 
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** Transistor resistance = Beta AC (30) times re
 
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*** re = 26 / Ie (10 mA in mA) = 26/10 =
 
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*** Beta AC * re = 30*2.6 = 78 ohms - predominates
 
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** All in parallel are 75.8 ohms
 
  
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=== Transformers ===
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[[FILE:W7ZOI_CAD.PNG]]
  
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* T1 50:75.8 ohms
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== SMT Build ==
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** n = sqrt(Zout/Zin) = sqrt(75.8/50) = 1.23
 
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** 9:11 turns ratio
 
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* T2 - different than Charlie's design since my Crystal filters are all 50 ohms in/out
 
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** 250:50 ohms
 
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** n = sqrt(250/50) = 2.23:1
 
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** 11:5 turns
 
  
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=== Charlie's Notes ===
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[[FILE:W7ZOI_TIA_SMD_3D.png]]
  
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[[FILE:IF Amp_0046A.jpg]]
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[[FILE:W7ZOI_TIA_SMT_CAD.PNG]]
  
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[[FILE:IF Amp_0046B.jpg]]
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== Videos ==
  
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[[FILE:IF Amp_0046C.jpg]]
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<video type="youtube">JjcxEYk9atg</video>
  
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[[FILE:IF Amp_0047A.jpg]]
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<video type="youtube">CpQK0W7TY5g</video>
  
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[[FILE:IF Amp_0047B.jpg]]
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<video type="youtube">7TtKE39TWpI</video>
  
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[[FILE:IF Amp_0047C.jpg]]
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<video type="youtube">T8lq8Qtjqe0</video>
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== Video ==
 
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<video type="youtube">CHdtoupH2Vg</video>
 
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<video type="youtube">YJTsWV2kzFY</video>
 
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<video type="youtube">xPFzFhM0ojE</video>
 
  
 
== Assembly Sheet ==
 
== Assembly Sheet ==
  
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* [[RF Amplifier Assembly Sheet]]
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* [[W7ZOI TIA Assembly Sheet - Rev 1]]

Revision as of 11:03, 12 November 2021

W7ZOI TIA 3D.png

W7ZOI Design

W7ZOI Schematic

W7ZOI SCHEMATIC.PNG

* Use

  • Between RF/LO mixer (IF output/input) and crystal filter
  • Between Crystal Filter and Product Detector / Balanced Modulator

FARHADPNG.PNG

Schematic in KiCAD

  • Single channel
  • With SPICE directives

W7ZOI SCHEMATIC KiCAD.PNG

  • Both channels
  • With SPICE directives

W7ZOI SCHEMATIC KiCAD-2.PNG

NGSPICE Simulation

W7ZOI Simulation KiCAD-3.PNG

  • Closely matches

W7ZOI Gainz.PNG

  • Across Band

W7ZOI Simulation KiCAD S2.PNG

CAD

W7ZOI CAD.PNG

SMT Build

W7ZOI TIA SMD 3D.png

W7ZOI TIA SMT CAD.PNG

Videos

Assembly Sheet

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