|
|
| Line 1: |
Line 1: |
| − | == Purchased Attenuators ==
| |
| | | | |
| − | === Programmable Attenuator ===
| |
| − |
| |
| − | * [[PE4302 RF Attenuator|PE4302 RF Attenuator board in my enclosure design]]
| |
| − |
| |
| − | [[file:PE4302_P1833-720px.jpg]]
| |
| − |
| |
| − | === Triple Attenuator ===
| |
| − |
| |
| − | * [[0/10/20/30 dB Attenuator]]
| |
| − |
| |
| − | [[file:ATTEN4_CHINA_PCB.PNG]]
| |
| − |
| |
| − | == Homebrew RF Attenuators ==
| |
| − |
| |
| − | [[file:Atten_30dB_20dV_P1812-720px.jpg]]
| |
| − | === 30 dB Attenuator ===
| |
| − |
| |
| − | * [http://leleivre.com/rf_pipad.html Pi Attenuator Calculator]
| |
| − |
| |
| − | [[file:Atten30dB_P116-720px.jpg]]
| |
| − |
| |
| − | [[file: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
| |
| − |
| |
| − | [[file:30dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
| |
| − |
| |
| − | [[file:30dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
| |
| − |
| |
| − | * LTSPICE Simulation
| |
| − |
| |
| − | [[file:LTSPice_30dB.PNG]]
| |
| − |
| |
| − | === 20 dB Attenuator ===
| |
| − |
| |
| − | [[file:Atten_20dB_P115-720px.jpg]]
| |
| − |
| |
| − | [[file: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)
| |
| − |
| |
| − | [[file:20dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
| |
| − |
| |
| − | [[file:20dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
| |
| − |
| |
| − | * LTSPICE Simulation
| |
| − |
| |
| − | [[file: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
| |
| − |
| |
| − | [[file:Atten_01_SMAs_720px.jpg]]
| |
| − |
| |
| − | * Cut "T" Shaped pads
| |
| − | ** I used nibbler
| |
| − | * Center fits between connector ground pins
| |
| − | * Glue down pads with Superglue
| |
| − |
| |
| − | [[file: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
| |
| − |
| |
| − | [[file:Atten_03_Solder CenterPads_720px.jpg]]
| |
| − |
| |
| − | * Solder side resistor(s)
| |
| − | * Leave room for center resistor(s)
| |
| − |
| |
| − | [[file:Atten_04_Solder Side_Resistors_720px.jpg]]
| |
| − |
| |
| − | * Measure side resistors from pad to ground
| |
| − | * Should match value
| |
| − | * Solder center resistor(s)
| |
| − |
| |
| − | [[file:Atten_05_Solder Center_Resistors_720px.jpg]]
| |
| − |
| |
| − | * Verify no shorts between centers and ground
| |
| − |
| |
| − | == Attenuator Design - Rev 2 ==
| |
| − |
| |
| − | [[FILE:ATTEN.PNG]]
| |
| − |
| |
| − | * SMA connectors
| |
| − | * Resistors
| |
| − | ** 1206
| |
| − | *** 1/4W
| |
| − | ** 1% values
| |
| − |
| |
| − | [[file:10dB_Attenuator.PNG]]
| |
| − |
| |
| − | === Parts ===
| |
| − |
| |
| − | {| class="wikitable"
| |
| − | ! 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
| |
| − |
| |
| − | [[file:ATTEN1_NanoVNA_40dB.png]]
| |
| − |
| |
| − | * Flat from 1-30 MHz
| |
| − | * S21
| |
| − |
| |
| − | [[file:ATTEN1_NanoVNA_40dB_1-30MHz.png]]
| |
| − |
| |
| − | * s11
| |
| − | * 1-900 MHz
| |
| − |
| |
| − | [[file:ATTEN1_NanoVNA_40dB_S11_1-100MHz.png]]
| |
| − |
| |
| − | * VSWR
| |
| − | * 1-900 MHz
| |
| − |
| |
| − | [[file: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
| |
| − |
| |
| − | [[FILE:ATTEN1_NanoVNA_DC-BLOCK_S21_50KHz-900MHz.png]]
| |
| − |
| |
| − | == Attenuator Charts ==
| |
| − |
| |
| − | [[file:dBm_vs_milliVolt_milliWatts.PNG]]
| |
| − |
| |
| − | [[file:dBm_vs_Volta_Watts.PNG]]
| |
| − |
| |
| − | [[file:dBm_vs_Volt_Watts.PNG]]
| |
| − |
| |
| − | == References ==
| |
| − |
| |
| − | * [http://leleivre.com/rf_pipad.html Attenuator Calculator] - Le Leivre.com
| |
| − | * [https://www.pasternack.com/t-calculator-pi-attn.aspx Attenuator Calculator] - Pasternak
| |
| − |
| |
| − | * Heavily inspired by Alan (W2AEW) video
| |
| − |
| |
| − | <video type="youtube">A5gGeV7CiQ0</video>
| |
| − |
| |
| − | [[file:W2AEW_Attns-01.PNG]]
| |
| − |
| |
| − | [[file:W2AEW_Attns-02.PNG]]
| |
| − |
| |
| − | [[file:W2AEW_Attns-03.PNG]]
| |
