Difference between pages "Kits and Parts Mixers" and "RF Attenuators"

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−
== Kits and Parts Mixers - Features in Common ==
+
== Purchased Attenuators ==
  
−
* Available as discrete diode or ADE-1 mixer cards from Kits and Parts
+
=== Programmable Attenuator ===
−
* LO, IF, RF Ports are all 50Ω
 
−
* +7dBm Local Oscillator injection level
 
−
** As measured into 50Ω load
 
−
*** Mixers are not linear and loads should not be measured at the mixer
 
−
* ~5dB RF > IF conversion loss in HF region
 
−
* Full Diplexer at the IF Port
 
−
* Board has pads (SMT or 1/8W resistor pads) for optional Attenuators on RF & LO Ports
 
−
* 3 pin, 0.1" pads at board edges allow SMA edge connectors to be used
 
−
* Mounting holes in all 4 corners
 
  
−
== Typical Application ==
+
* [[PE4302 RF Attenuator|PE4302 RF Attenuator board in my enclosure design]]
  
−
* 7 MHz RF, 40 M band
+
[[file:PE4302_P1833-720px.jpg]]
−
* 16 MHz LO
 
−
** Si5351A square wave drive
 
−
* 9 MHz (difference 16-7=9) IF feeds Crystal Filter
 
−
** SSB or CW [[Crystal Filter Design|Crystal Filter Design]] - 9 MHz nominal
 
−
*** [[Crystal Filter Design#SSB 4 Crystal Filter on Kits and Parts Board|SSB4 Crystal filter]]
 
−
*** [[SSB6_Design|SSB6 Design Crystal filter]]
 
−
*** [[Crystal_Filter_Design#CW 5 Crystal Filter on Kits and Parts Board|CW5 Crystal Filter]]
 
−
* Use Si5351 to drive LO and/or RF ports
 
  
−
=== Si5351A Drive Level ===
+
=== Triple Attenuator ===
  
−
* [https://www.skyworksinc.com/-/media/Skyworks/SL/documents/public/data-sheets/Si5351-B.pdf Si5351A] used to drive LO and/or RF ports
+
* [[0/10/20/30 dB Attenuator]]
−
** 3 outputs
 
−
** LO at full level (+7dBm)
 
−
** RF at various levels with attenuators to drop to expected RF signal levels
 
−
* Don't want more than 7 dBm into LO or RF ports
 
−
* Two Si5351 Designs to drive ADE-1 LO or RF ports
 
−
** [[VFO-001]]
 
−
*** Uses the Si5351 without external drivers
 
−
*** Set drive levels to 2mA, 4mA, 6mA or 8mA
 
−
** [[VFO-003]] - Adds 50Ω drivers
 
−
*** Level is fixed
 
−
*** Three 74AC14 parts with 150 ohms outputs paralleled
 
−
*** 13 dBm output
 
−
*** Install 6 dBm attenuator on board (13-6=7)
 
  
−
==== VFO-001 drive ====
+
[[file:ATTEN4_CHINA_PCB.PNG]]
  
−
* The RMS value is for square-wave voltages whose pulse duration (ti) and pause (tp) have the same length:
+
== Homebrew RF Attenuators ==
  
−
[[file:RMS-SquareWave.PNG]]
+
[[file:Atten_30dB_20dV_P1812-720px.jpg]]
 +
=== 30 dB Attenuator ===
  
−
* [https://www.redcrab-software.com/en/Calculator/Electrics/Rectangular-Voltage-RMS-Value#:~:text=The%20rms%20value%20is%20for%20square-wave%20voltages%20whose,rms%20value%20is%20equal%20to%20the%20peak%20value Square Wave Calculator]
+
* [http://leleivre.com/rf_pipad.html Pi Attenuator Calculator]
  
−
[[file:RMS-SquareWave-2.PNG]]
+
[[file:Atten30dB_P116-720px.jpg]]
  
−
* Drive level of 3.3V
+
[[file:30dB_Attenuator.PNG]]
  
−
[[file:RMS-SquareWave-3.PNG]]
+
* Built
 +
** Standard 5% resistor values
 +
** R1 = 820 in parallel with 22K = 790.6 ohms
 +
** R2 = 2 paralleled 120 Ohm 1/4W resistors paralleled with 470 ohms = 53.2 ohms
 +
** Flat from 0-30 MHz
 +
** Measured attenuation is flat
 +
*** -30.01dB at 1 MHz
 +
*** -30.24dB at 30 MHz
 +
** Input Impedance - 53.1 ohms, 21.3nF
 +
** SWR 1.06
 +
** 1/2W max (5VDC max, 0 ohm source)
  
−
* 100 mW is 20 dBm
+
* NanoVNA scan data
−
* ADE-1 needs 7 dBm level
 
−
* Would need a 13 dB attenuator
 
−
** Not actually true
 
−
*** Although the Si5351 datasheet says it drives 50 Ohms loads this is not exactly the case
 
−
*** Drive levels are controlled by the output current setting
 
−
* Si5351A outputs measured on [[VFO-001]]
 
−
** Drive Level 2 mA = 0.2 dBm
 
−
** Drive Level 4 mA = 6.2 dBm << Use this level
 
−
** Drive Level 6 mA = 9.7 dBm
 
−
** Drive Level 8 mA = 11.7 dBm
 
  
−
==== VFO-003 drive ====
+
[[file:30dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
  
−
* [[VFO-003#Output_Power_-_Power_Calculation|VFO-003 Output_Power - Power Calculation]]
+
[[file:30dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
  
−
* RMS Voltage of square wave
+
* LTSPICE Simulation
  
−
[[file:SquareWace-3.3V.PNG]]
+
[[file:LTSPice_30dB.PNG]]
  
−
* [https://www.redcrab-software.com/en/Calculator/Electrics/Rectangular-Voltage-RMS-Value Square Wave Calculator]
+
=== 20 dB Attenuator ===
−
* 2.33V^2/100 = 0.0542W
 
−
* Power is split between Source and load resistors
 
−
* 0.02714W
 
  
−
* dBm Calculation
+
[[file:Atten_20dB_P115-720px.jpg]]
  
−
* [https://www.rapidtables.com/convert/power/dbm-converter.html mW to dBm calculator]
+
[[file:20dB_Attenuator.PNG]]
  
−
[[file:SquareWave-3.3V_dBm.PNG]]
+
* Build
 +
** Standard 5% resistor values
 +
** R1 = 2 of 510 in parallel also in parallel with 8.2K = 247.3 ohms
 +
** R2 = 2 paralleled 150 Ohm 1/2W resistors paralleled with 330 ohms = 61.11 ohms
 +
** Flat from 0-30 MHz
 +
** Measured attenuation is flat
 +
** Input Impedance - tbd ohms, tbd nF
 +
** SWR tbd
 +
** 1W max (8.6 V max, 0 ohm source)
  
−
* Expect 14.3 dBm drive
+
[[file:20dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
−
* Measured 12.6 dBm with [[NanoVNA]] - Pretty close
 
−
* 6 dB attenuator to reduce for Level 7 mixers (like the ADE-1 mixer)
 
  
−
== Kits and Parts ADE-1 Mixer ==
+
[[file:20dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
  
−
* [https://kitsandparts.com/ADE.php Kits and Parts Mixer]
+
* LTSPICE Simulation
−
* Mini-Circuits ADE-1+ Double Balanced Diode Mixer with built in 50Ω transformers
 
−
** [https://www.minicircuits.com/pdfs/ADE-1+.pdf ADE-1+ Datasheet]
 
−
* Not necessary to build and tune diplexer first if using [[NanoVNA]] and/or [[tinySA]]
 
−
** Only 1 cap adjust
 
−
** Inductors can also be spread/compressed if needed
 
−
* Available from [https://kitsandparts.com/ADE.php Kits and Parts] as bare PCB or kit of parts
 
−
* Bare board - $5
 
−
* Kit - $14
 
−
** Good deal since the [https://www.mouser.com/ProductDetail/Mini-Circuits/ADE-1%2b?qs=xZ%2FP%252Ba9zWqZNkkNe3uAsRQ%3D%3D mixer itself is $6]
 
  
−
[[file:ADE-1.SCH.png]]
+
[[file:LTSPice_20dB.PNG]]
  
−
[[file:ADE-1.PCB.png]]
+
=== Attenuator Construction ===
  
−
==== Toroid Winding Direction ====
+
* Single side copper clad PCB
 +
** Approx 2"x1"
 +
* Clean with steel wool
 +
* Solder SMA connectors
 +
** Use large alligator clips to hold while soldering
 +
** Solder on sides only
  
−
* Toroids needs to be wound to match the pad locations/offsets on the PCB
+
[[file:Atten_01_SMAs_720px.jpg]]
  
−
[[file:toroid-cw.jpg]]
+
* Cut "T" Shaped pads
 +
** I used nibbler
 +
* Center fits between connector ground pins
 +
* Glue down pads with Superglue
  
−
=== ADE-1 Schematic ===
+
[[file:Atten_02_Pads_720px.jpg]]
  
−
[[file:ADE-1_Schematic.PNG]]
+
* Solder center pin with big solder blob
 +
** A bit too high for direct contact
 +
* Verify raised pad does not short to ground
  
−
=== Performance ===
+
[[file:Atten_03_Solder CenterPads_720px.jpg]]
  
−
[[file:Chart_dBm-to-Volts.PNG]]
+
* Solder side resistor(s)
 +
* Leave room for center resistor(s)
  
−
[[file:ADE-1_Performance.PNG]]
+
[[file:Atten_04_Solder Side_Resistors_720px.jpg]]
  
−
[[file:ADE-1_ElectricalSpecs.PNG]]
+
* Measure side resistors from pad to ground
 +
* Should match value
 +
* Solder center resistor(s)
  
−
=== Port VWSR ===
+
[[file:Atten_05_Solder Center_Resistors_720px.jpg]]
  
−
* Measured VSWR of 2.23 at 9 MHz with NanoVNA matches spec nicely
+
* Verify no shorts between centers and ground
  
−
[[file:ADE-1_LO_VSWR.PNG]]
+
== Attenuator Design - Rev 2 ==
  
−
[[file:ADE-1_IF_VSWR.PNG]]
+
[[FILE:ATTEN.PNG]]
  
−
[[file:ADE-1_RF_VSWR.PNG]]
+
* SMA connectors
 +
* Resistors
 +
** 1206
 +
*** 1/4W
 +
** 1% values
  
−
=== ADE-1 Measurements ===
+
[[file:10dB_Attenuator.PNG]]
  
−
==== NanoVNA Measurements ====
+
=== Parts ===
  
−
* No RF in
+
{| class="wikitable"
−
* LO driven by NanoVNA Tx
+
! Mfr. #
−
** About -10dBm output
+
! Manufacturer
−
* IF output to NanoVNA Rx
+
! Customer #
−
* IF at 9 MHz
+
! Qty
−
** VSWR: 2.233
+
! R1/R2
−
** S21 Gain: -67 dB
+
! Description
 +
|-
 +
| RK73H2BTTE17R8F
 +
| KOA Speer
 +
| ATTEN_03DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 1/4W 17.8 ohms 1%
 +
|-
 +
| RC1206FR-07294RL
 +
| YAGEO
 +
| ATTEN_03DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 294 ohms 1/4W 1206 1%
 +
|-
 +
| RK73H2BTTD37R4F
 +
| KOA Speer
 +
| ATTEN_06DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 1/4W 37.4 ohms 1%
 +
|-
 +
| CRCW1206150RFKEAC
 +
| Vishay
 +
| ATTEN_06DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 1/4Watt 150 ohms 1%
 +
|-
 +
| RC1206FR-0771R5L
 +
| YAGEO
 +
| ATTEN_10DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 71.5 ohms 1/4W 1206 1%
 +
|-
 +
| RC1206FR-0797R6L
 +
| YAGEO
 +
| ATTEN_10DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 97.6 ohms 1/4W 1206 1%
 +
|-
 +
| RK73H2BTTD1070F
 +
| KOA Speer
 +
| ATTEN_13DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 1/4W 107 ohms 1%
 +
|-
 +
| RC1206FR-0778R7L
 +
| YAGEO
 +
| ATTEN_13DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 78.7 ohms 1/4W 1206 1%
 +
|-
 +
| AC1206FR-07249RL
 +
| YAGEO
 +
| ATTEN_20DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 249 ohms 1/4W 1206 1%
 +
|-
 +
| RK73H2BTTDD61R9F
 +
| KOA Speer
 +
| ATTEN_20DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 61.9 ohms 1%
 +
|-
 +
| RK73H2BTTD7870F
 +
| KOA Speer
 +
| ATTEN_30DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 1/4W 787 ohms 1%
 +
|-
 +
| AC1206FR-0753R6L
 +
| YAGEO
 +
| ATTEN_30DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 53.6 ohms 1/4W 1206 1%
 +
|-
 +
| RC1206FR-072K49L
 +
| YAGEO
 +
| ATTEN_40DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 2.49k ohms 1/4W 1206 1%
 +
|-
 +
| RK73H2BTTD51R0F
 +
| KOA Speer
 +
| ATTEN_40DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 1/4W 51 ohms 1%
 +
|-
 +
| RK73H2BTTDD49R9F
 +
| KOA Speer
 +
| ATTEN_50_60DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 49.9 ohms 1%
 +
|-
 +
| RC1206FR-077K87L
 +
| YAGEO
 +
| ATTEN_50DB
 +
| 1
 +
| R1
 +
| Resistors - SMD 7.87k ohms 1/4W 1206 1%
 +
|-
 +
| RC1206FR-0726K1L
 +
| YAGEO
 +
| ATTEN_60DB
 +
| 2
 +
| R2
 +
| Resistors - SMD 26.1k ohms 1/4W 1206 1%
 +
|-
 +
|}
  
−
[[file:ADE-1.NanoVNA_LO-to-IF.png]]
+
=== Measurements ===
  
 
* NanoVNA
 
* NanoVNA
−
* No LO in
+
* S21 gain
−
* RF driven by NanoVNA Tx
+
* 1-900 MHz scan
−
* IF output to NanoVNA Rx
+
* Calibrated with cable on thru
−
* IF at 9 MHz
 
−
** VSWR: 2.216
 
−
** S21 Gain: -42 dB
 
  
−
[[file:ADE-1.NanoVNA_RF-to-IF.png]]
+
==== 40 dB Attenuator ====
  
−
* Scanning from 1 to 100 MHz
+
* Flat from 1-600 MHz
 +
* Higher attenuation past 600 MHz
 +
* -39.9 dB at 14 MHz
 +
* S21
  
−
[[file:ADE-1.NanoVNA_RF-to-IF_1-100MHz.png]]
+
[[file:ATTEN1_NanoVNA_40dB.png]]
  
−
==== tinySA Measurements ====
+
* Flat from 1-30 MHz
 +
* S21
  
−
===== LO to IF port isolation =====
+
[[file:ATTEN1_NanoVNA_40dB_1-30MHz.png]]
  
−
* Driven by [[VFO-001]] 3.3V squarewave output
+
* s11
−
** Signal level about 0.5 dBm
+
* 1-900 MHz
−
** CLK0 = 9 MHz into LO port
 
−
* Monitor IF output from mixer on tinySA
 
−
** Output through 20 dB attenuator (tinySA set to -20dB gain)
 
  
−
[[file:ADE-1.tinySA_RF-to-IF_9Mhz-center.png]]
+
[[file:ATTEN1_NanoVNA_40dB_S11_1-100MHz.png]]
  
−
===== Mixer Operation =====
+
* VSWR
 +
* 1-900 MHz
  
−
* Mixer is driven by [[VFO-001]] 3.3V squarewave outputs
+
[[file:ATTEN1_NanoVNA_40dB_VSWR_1-100MHz.png]]
−
** Signal output levels about 0.5 dBm
 
−
** CLK0 = RF @7 MHz [[VFO-001]] output with 30 dB attenuator
 
−
** CLK1 = LO @16 MHz no attenuator
 
−
* Monitor IF output from mixer on [[tinySA]]
 
−
** IF out to tinySA with 20 dB attenuator (tinySA set to -20dB gain)
 
  
−
[[file:ADE-1.tinySA_LO-16MHz_RF-7MHz-to-IF_9Mhz-center.png]]
+
== DC Block ==
  
−
* Same but 9 MHz picked out
+
* Use same PCB
−
* Approx. 8 dB insertion loss
+
** Install 0.1uF cap between the two SMAs
 +
* S21 of -0.8 dB at 50 KHz
 +
* S21 of 0.44 dB at 900 MHz
  
−
[[file:ADE-1.tinySA_LO-16MHz_RF-7MHz-to-IF_9Mhz-at9MHz.png]]
+
[[FILE:ATTEN1_NanoVNA_DC-BLOCK_S21_50KHz-900MHz.png]]
  
−
* Look at 7 MHz RF freq on IF output
+
== Attenuator Charts ==
  
−
[[file:ADE-1.tinySA_LO-16MHz_RF-7MHz-to-IF_9Mhz-at7MHz.png]]
+
[[file:dBm_vs_milliVolt_milliWatts.PNG]]
  
−
* Look at 16 MHz LO freq on IF output
+
[[file:dBm_vs_Volta_Watts.PNG]]
  
−
[[file:ADE-1.tinySA_LO-16MHz_RF-7MHz-to-IF_9Mhz-at16MHz.png]]
+
[[file:dBm_vs_Volt_Watts.PNG]]
  
−
===== Mixer with SSB4 IF Crystal Filter =====
+
== References ==
  
−
* Mixer is driven by [[VFO-001]] 3.3V squarewave outputs
+
* [http://leleivre.com/rf_pipad.html Attenuator Calculator] - Le Leivre.com
−
** Signal output levels about 0.5 dBm
+
* [https://www.pasternack.com/t-calculator-pi-attn.aspx Attenuator Calculator] - Pasternak
−
** CLK0 = RF @7 MHz [[VFO-001]] output with 20 dB attenuator
 
−
** CLK1 = LO @15.998,6 MHz no attenuator
 
−
*** Adjusted to center of the [[W7ZOI_Filters_on_Kits_and_Parts_Boards#SSB_4_Crystal_Filter_on_Kits_and_Parts_Board|SSB4 Crystal filter]]
 
−
* IF output from mixer to [[W7ZOI_Filters_on_Kits_and_Parts_Boards#SSB_4_Crystal_Filter_on_Kits_and_Parts_Board|SSB4 Crystal filter]] input
 
−
* Monitor [[W7ZOI_Filters_on_Kits_and_Parts_Boards#SSB_4_Crystal_Filter_on_Kits_and_Parts_Board|SSB4 Crystal filter]] output on [[tinySA]]
 
−
** No attenuator on IF output into tinySA
 
  
−
[[file:tinySA_ADE-1-MixerwCystalFilter_9MHz_center.png]]
+
* Heavily inspired by Alan (W2AEW) video
  
−
* Scan from 1 to 30 MHz
+
<video type="youtube">A5gGeV7CiQ0</video>
−
* Note other signals are now well into the noise floor of the [[tinySA]]
 
−
** LO present but down
 
  
−
[[file:tinySA_ADE-1-MixerwCystalFilter_1_to_30MHz.png]]
+
[[file:W2AEW_Attns-01.PNG]]
  
−
* 16 MHz LO level
+
[[file:W2AEW_Attns-02.PNG]]
−
* 16 dB lower with crystal filter
 
  
−
[[file:tinySA_ADE-1-MixerwCystalFilter_16MHz_LO-Suppression.png]]
+
[[file:W2AEW_Attns-03.PNG]]
−
 
 
−
===== Mixer with CW5 IF Crystal Filter =====
 
−
 
 
−
* Mixer is driven by [[VFO-001]] 3.3V squarewave outputs
 
−
** Signal output levels about 0.5 dBm
 
−
** CLK0 = RF @7 MHz [[VFO-001]] output with 20 dB attenuator
 
−
** CLK1 = LO @15.997,9 MHz no attenuator
 
−
*** Adjusted to center of the [[W7ZOI_Filters_on_Kits_and_Parts_Boards#CW_5_Crystal_Filter_on_Kits_and_Parts_Board|CW5 Crystal filter]]
 
−
* IF output from mixer to [[W7ZOI_Filters_on_Kits_and_Parts_Boards#C_W5_Crystal_Filter_on_Kits_and_Parts_Board|CW5 Crystal filter]] input
 
−
* Monitor [[W7ZOI_Filters_on_Kits_and_Parts_Boards#CW_5_Crystal_Filter_on_Kits_and_Parts_Board|CW5 Crystal filter]] output on [[tinySA]]
 
−
** No attenuator on IF output into tinySA
 
−
 
 
−
[[file:tinySA_ADE-1-Mixerw_CW5CystalFilter_9MHz_center.png]]
 
−
 
 
−
* Scan from 1 to 30 MHz
 
−
* Note other signals are now well into the noise floor of the [[tinySA]]
 
−
** LO present but down
 
−
 
 
−
[[file:tinySA_ADE-1-Mixerw_CW5CystalFilter_9MHz_1to30MHz.png]]
 
−
 
 
−
* 16 MHz LO level
 
−
* 16 dB lower with crystal filter
 
−
 
 
−
[[file:tinySA_ADE-1-MixerwCW5CystalFilter_16MHz_LO-Suppression.png]]
 
−
 
 
−
===== Mixer with CW3 IF Crystal Filter =====
 
−
 
 
−
* Mixer is driven by [[VFO-001]] 3.3V squarewave outputs
 
−
** Signal output levels about 0.5 dBm
 
−
** CLK0 = RF @7 MHz [[VFO-001]] output with 20 dB attenuator
 
−
** CLK1 = LO @15.997,7 MHz no attenuator
 
−
*** Adjusted to center of the [[W7ZOI_Filters_on_Kits_and_Parts_Boards#CW3_Crystal_Filter_on_Kits_and_Parts_Board|CW3 Crystal filter]]
 
−
* IF output from mixer to [[W7ZOI_Filters_on_Kits_and_Parts_Boards#CW3_Crystal_Filter_on_Kits_and_Parts_Board|CW3 Crystal filter]] input
 
−
* Monitor [[W7ZOI_Filters_on_Kits_and_Parts_Boards#CW3_Crystal_Filter_on_Kits_and_Parts_Board|CW3 Crystal filter]] output on [[tinySA]]
 
−
** No attenuator on IF output into tinySA
 
−
 
 
−
[[file:tinySA_ADE-1-Mixerw_CW3CystalFilter_9MHz_center.png]]
 
−
 
 
−
* Scan from 1 to 30 MHz
 
−
* Note other signals are now well into the noise floor of the [[tinySA]]
 
−
** LO present but down
 
−
 
 
−
[[file:tinySA_ADE-1-Mixerw_CW3CystalFilter_9MHz_1to30MHz.png]]
 
−
 
 
−
* 16 MHz LO level
 
−
* 16 dB lower with crystal filter
 
−
 
 
−
[[file:tinySA_ADE-1-MixerwCW3CystalFilter_16MHz_LO-Suppression.png]]
 
−
 
 
−
== Mixer as Product Detector ==
 
−
 
 
−
* RF is 9 MHz from IF stage
 
−
* LO is 9 MHz BFO
 
−
** Minor adjustments to get to side of the base band offset
 
−
* IF output is audio
 
−
** Mixer goes down to DC
 
−
** IF needs Audio Filter
 
−
** [https://www.mouser.com/ProductDetail/871-B78108S1155J 1.5 mH inductor]
 
−
** 0.33 uF cap/50 ohms terminates higher frequencies
 
−
* LTSpice Simulation
 
−
 
 
−
[[file:LP_Audio.PNG]]
 
−
 
 
−
* Circuit Mods
 
−
 
 
−
[[file:ADE-1_AF_Filter.PNG]]
 
−
 
 
−
* IF section
 
−
 
 
−
[[file:ADE-1_AF_Filter_Physicals.PNG]]
 
−
 
 
−
== Bridged Tee Diplexer ==
 
−
 
 
−
Diplexor is a bandpass/band-stop filter popularized by [https://www.youtube.com/watch?v=iVUv8C-8g-Y Joe Reisert W1JR] that is used after a double Balanced Mixer to provide a 50 ohm termination to all frequencies at the mixer's IF port, and to the following amplifier stage.  Maintaining a consistent load at the mixer avoids overload and Inter-Modulation Distortion (IMD) effects that these mixers are prone to when not properly terminated.
 
−
 
 
−
=== LTSpice simulation ===
 
−
 
 
−
* 9 MHz
 
−
* FT37-67, 20T-12" = 8 uH
 
−
* T37-17, 13T-10" = 250 nH
 
−
* C2 adjusts peak from left to right
 
−
 
 
−
[[FILE:DIPLEXER_SPICE_SIM.PNG]]
 
−
 
 
−
* [https://www.changpuak.ch/electronics/calc_16a.php Diplexer Calculator (Bridged Tee) Diplexer Calculator]
 
−
* [https://www.qsl.net/g3oou/mixerterminations.html Mixer Diplexer description]
 
−
 
 
−
[[file:Diplexer.PNG]]
 
−
 
 
−
[[file:Diplexer_pass.PNG]]
 
−
 
 
−
<video type="youtube">zOk_0IiIgZY</video>
 
−
 
 
−
=== Adjust IF Diplexer C1 (ADE-1) ===
 
−
 
 
−
* Drive RF port from [[NanoVNA]]
 
−
** Nominal 0 dBm drive level
 
−
* IF port is output
 
−
** Listen on IF port on [[NanoVNA]]
 
−
* No drive on LO
 
−
* 9 MHz is IF design frequency
 
−
* Nano VNA set to scan from 1 Mhz to 30 MHz
 
−
** Shows peak expected signal around 9 MHz
 
−
 
 
−
[[file:ADE-1.NanoVNA_RF-to-IF.png]]
 
−
 
 
−
* Scan from 8 to 10 MHz
 
−
* Adjust C1 to peak near 9 MHz
 
−
** Eliminate double peaks
 
−
 
 
−
[[file:ADE-1.NanoVNA_RF-to-IF_8-10MHz.png]]
 
−
 
 
−
== Kits and Parts Diode Mixer ==
 
−
 
 
−
* [https://kitsandparts.com/DBDM.php Double Balanced Diode Ring Mixer Kit]
 
−
* Not necesary to build and tune diplexer first is using a [[NanoVNA]] or [[tinySA]] to adjust
 
−
* Available from [https://kitsandparts.com/ADE.php Kits and Parts] as bare PCB or kit of parts
 
−
* Bare board - $5
 
−
* Kit - $12
 
−
 
 
−
[[file:DBDM.SCH.png]]
 
−
 
 
−
[[file:DBDM.PCB.png]]
 
−
 
 
−
== Videos ==
 
−
 
 
−
<video type="youtube">GvadQpkZ8l0</video>
 
−
 
 
−
<video type="youtube">Mm7WfVzr1ao</video>
 
−
 
 
−
<video type="youtube">7qhY_NMNzxw</video>
 

Revision as of 10:38, 23 October 2021

Purchased Attenuators

Programmable Attenuator

PE4302 P1833-720px.jpg

Triple Attenuator

ATTEN4 CHINA PCB.PNG

Homebrew RF Attenuators

Atten 30dB 20dV P1812-720px.jpg

30 dB Attenuator

Atten30dB P116-720px.jpg

30dB Attenuator.PNG

  • Built
    • Standard 5% resistor values
    • R1 = 820 in parallel with 22K = 790.6 ohms
    • R2 = 2 paralleled 120 Ohm 1/4W resistors paralleled with 470 ohms = 53.2 ohms
    • Flat from 0-30 MHz
    • Measured attenuation is flat
      • -30.01dB at 1 MHz
      • -30.24dB at 30 MHz
    • Input Impedance - 53.1 ohms, 21.3nF
    • SWR 1.06
    • 1/2W max (5VDC max, 0 ohm source)
  • NanoVNA scan data

30dB Attenuator NanoVNA Setup Curve 900MHz.PNG

30dB Attenuator NanoVNA Data 900MHz.PNG

  • LTSPICE Simulation

LTSPice 30dB.PNG

20 dB Attenuator

Atten 20dB P115-720px.jpg

20dB Attenuator.PNG

  • Build
    • Standard 5% resistor values
    • R1 = 2 of 510 in parallel also in parallel with 8.2K = 247.3 ohms
    • R2 = 2 paralleled 150 Ohm 1/2W resistors paralleled with 330 ohms = 61.11 ohms
    • Flat from 0-30 MHz
    • Measured attenuation is flat
    • Input Impedance - tbd ohms, tbd nF
    • SWR tbd
    • 1W max (8.6 V max, 0 ohm source)

20dB Attenuator NanoVNA Setup Curve 900MHz.PNG

20dB Attenuator NanoVNA Data 900MHz.PNG

  • LTSPICE Simulation

LTSPice 20dB.PNG

Attenuator Construction

  • Single side copper clad PCB
    • Approx 2"x1"
  • Clean with steel wool
  • Solder SMA connectors
    • Use large alligator clips to hold while soldering
    • Solder on sides only

Atten 01 SMAs 720px.jpg

  • Cut "T" Shaped pads
    • I used nibbler
  • Center fits between connector ground pins
  • Glue down pads with Superglue

Atten 02 Pads 720px.jpg

  • Solder center pin with big solder blob
    • A bit too high for direct contact
  • Verify raised pad does not short to ground

Atten 03 Solder CenterPads 720px.jpg

  • Solder side resistor(s)
  • Leave room for center resistor(s)

Atten 04 Solder Side Resistors 720px.jpg

  • Measure side resistors from pad to ground
  • Should match value
  • Solder center resistor(s)

Atten 05 Solder Center Resistors 720px.jpg

  • Verify no shorts between centers and ground

Attenuator Design - Rev 2

ATTEN.PNG

  • SMA connectors
  • Resistors
    • 1206
      • 1/4W
    • 1% values

10dB Attenuator.PNG

Parts

Mfr. # Manufacturer Customer # Qty R1/R2 Description
RK73H2BTTE17R8F KOA Speer ATTEN_03DB 1 R1 Resistors - SMD 1/4W 17.8 ohms 1%
RC1206FR-07294RL YAGEO ATTEN_03DB 2 R2 Resistors - SMD 294 ohms 1/4W 1206 1%
RK73H2BTTD37R4F KOA Speer ATTEN_06DB 1 R1 Resistors - SMD 1/4W 37.4 ohms 1%
CRCW1206150RFKEAC Vishay ATTEN_06DB 2 R2 Resistors - SMD 1/4Watt 150 ohms 1%
RC1206FR-0771R5L YAGEO ATTEN_10DB 1 R1 Resistors - SMD 71.5 ohms 1/4W 1206 1%
RC1206FR-0797R6L YAGEO ATTEN_10DB 2 R2 Resistors - SMD 97.6 ohms 1/4W 1206 1%
RK73H2BTTD1070F KOA Speer ATTEN_13DB 1 R1 Resistors - SMD 1/4W 107 ohms 1%
RC1206FR-0778R7L YAGEO ATTEN_13DB 2 R2 Resistors - SMD 78.7 ohms 1/4W 1206 1%
AC1206FR-07249RL YAGEO ATTEN_20DB 1 R1 Resistors - SMD 249 ohms 1/4W 1206 1%
RK73H2BTTDD61R9F KOA Speer ATTEN_20DB 2 R2 Resistors - SMD 61.9 ohms 1%
RK73H2BTTD7870F KOA Speer ATTEN_30DB 1 R1 Resistors - SMD 1/4W 787 ohms 1%
AC1206FR-0753R6L YAGEO ATTEN_30DB 2 R2 Resistors - SMD 53.6 ohms 1/4W 1206 1%
RC1206FR-072K49L YAGEO ATTEN_40DB 1 R1 Resistors - SMD 2.49k ohms 1/4W 1206 1%
RK73H2BTTD51R0F KOA Speer ATTEN_40DB 2 R2 Resistors - SMD 1/4W 51 ohms 1%
RK73H2BTTDD49R9F KOA Speer ATTEN_50_60DB 2 R2 Resistors - SMD 49.9 ohms 1%
RC1206FR-077K87L YAGEO ATTEN_50DB 1 R1 Resistors - SMD 7.87k ohms 1/4W 1206 1%
RC1206FR-0726K1L YAGEO ATTEN_60DB 2 R2 Resistors - SMD 26.1k ohms 1/4W 1206 1%

Measurements

  • NanoVNA
  • S21 gain
  • 1-900 MHz scan
  • Calibrated with cable on thru

40 dB Attenuator

  • Flat from 1-600 MHz
  • Higher attenuation past 600 MHz
  • -39.9 dB at 14 MHz
  • S21

ATTEN1 NanoVNA 40dB.png

  • Flat from 1-30 MHz
  • S21

ATTEN1 NanoVNA 40dB 1-30MHz.png

  • s11
  • 1-900 MHz

ATTEN1 NanoVNA 40dB S11 1-100MHz.png

  • VSWR
  • 1-900 MHz

ATTEN1 NanoVNA 40dB VSWR 1-100MHz.png

DC Block

  • Use same PCB
    • Install 0.1uF cap between the two SMAs
  • S21 of -0.8 dB at 50 KHz
  • S21 of 0.44 dB at 900 MHz

ATTEN1 NanoVNA DC-BLOCK S21 50KHz-900MHz.png

Attenuator Charts

DBm vs milliVolt milliWatts.PNG

DBm vs Volta Watts.PNG

DBm vs Volt Watts.PNG

References

  • Heavily inspired by Alan (W2AEW) video

W2AEW Attns-01.PNG

W2AEW Attns-02.PNG

W2AEW Attns-03.PNG

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