Difference between revisions of "0/10/20/30 dB Attenuator"
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| − | == 0 | + | [[file:ATTEN4_CHINA_PCB.PNG]] |
| + | |||
| + | == Specs == | ||
| + | |||
| + | DC-4.0GHz 200mW DC 4.0GHz RF Fixed Attenuator SMA Double Female Head 0dB 10dB 20dB 30dB | ||
| + | |||
| + | |||
| + | * From the [https://www.aliexpress.com/item/4000333427604.html?spm=a2g0s.9042311.0.0.52b34c4d4UyEIF AliExpress listing] | ||
| + | ** $5 with shipping (2021-10) | ||
| + | * Frequency range: DC - 4.0GHz | ||
| + | * Maximum power: 23dBm (200mW) | ||
| + | * Standing wave ratio: ≤ 1.20 | ||
| + | * System impedance: 50Ω | ||
| + | * RF interface: SMA double female head (Outer screw inner hole) | ||
| + | * Attenuation: | ||
| + | ** Direct: 0dB (reference) | ||
| + | ** Level 1: 10 ± 0.8 dB | ||
| + | ** Level 2: 20 ± 1.1 dB | ||
| + | ** Level 3: 30 ± 1.5dB | ||
| + | |||
| + | == Measurements == | ||
| + | |||
| + | * Characterized filters uinf NanoVNA | ||
| + | ** 1 to 900 MHz (card spec is up to 4 GHz) | ||
| + | ** Through-calibrated with SMA barrel and same cables was flat | ||
| − | [[file: | + | === 0 dB === |
| + | |||
| + | [[file:ATTEN_0DB_1MHz_TO_900MHz.png]] | ||
| + | |||
| + | === 10 dB === | ||
| + | |||
| + | [[file:ATTEN_10DB_1MHz_TO_900MHz.png]] | ||
| + | |||
| + | === 20 dB === | ||
| + | |||
| + | [[file:ATTEN_20DB_1MHz_TO_900MHz.png]] | ||
| + | |||
| + | === 30 dB === | ||
| + | |||
| + | [[file:ATTEN_30DB_1MHz_TO_900MHz.png]] | ||
| + | |||
| + | == Calibrating NanoVNA through the card == | ||
| + | |||
| + | * Calibrate on card 0 dB (pass-through connections) | ||
| + | |||
| + | === 0 dB === | ||
| + | |||
| + | [[file:ATTEN_0DB_1MHz_TO_900MHz_Cal.png]] | ||
| + | |||
| + | === 10 dB === | ||
| + | |||
| + | [[file:ATTEN_10DB_1MHz_TO_900MHz_CalOnBoard.png]] | ||
| + | |||
| + | === 20 dB === | ||
| + | |||
| + | [[file:ATTEN_20DB_1MHz_TO_900MHz_CalOnBoard.png]] | ||
| + | |||
| + | === 30 dB === | ||
| + | |||
| + | [[file:ATTEN_30DB_1MHz_TO_900MHz_CalOnBoard.png]] | ||
| + | |||
| + | == Analysis of Results == | ||
| + | |||
| + | * Board uses 5% (3-digits) resistors | ||
| + | ** Can result be 1dB with 5% resistors? | ||
| + | * Tracks are wide but 50 Ohms? | ||
| + | * 0805 resistors limit power handling to 200 mW max | ||
| + | * Lots of ground stitching | ||
| + | * Compared to Homebrew attenuator | ||
| + | ** Homebrew is more accurate in DC-100 MHz range | ||
| + | ** Leads may act as inductors/capacitors | ||
| + | |||
| + | [[file:ATTEN_30DB(HOMEBREWvsPURCHASED)_1MHz_TO_900MHz.png]] | ||
| + | |||
| + | == Improvements in design == | ||
Latest revision as of 20:41, 3 October 2021
Contents
Specs
DC-4.0GHz 200mW DC 4.0GHz RF Fixed Attenuator SMA Double Female Head 0dB 10dB 20dB 30dB
- From the AliExpress listing
- $5 with shipping (2021-10)
- Frequency range: DC - 4.0GHz
- Maximum power: 23dBm (200mW)
- Standing wave ratio: ≤ 1.20
- System impedance: 50Ω
- RF interface: SMA double female head (Outer screw inner hole)
- Attenuation:
- Direct: 0dB (reference)
- Level 1: 10 ± 0.8 dB
- Level 2: 20 ± 1.1 dB
- Level 3: 30 ± 1.5dB
Measurements
- Characterized filters uinf NanoVNA
- 1 to 900 MHz (card spec is up to 4 GHz)
- Through-calibrated with SMA barrel and same cables was flat
0 dB
10 dB
20 dB
30 dB
Calibrating NanoVNA through the card
- Calibrate on card 0 dB (pass-through connections)
0 dB
10 dB
20 dB
30 dB
Analysis of Results
- Board uses 5% (3-digits) resistors
- Can result be 1dB with 5% resistors?
- Tracks are wide but 50 Ohms?
- 0805 resistors limit power handling to 200 mW max
- Lots of ground stitching
- Compared to Homebrew attenuator
- Homebrew is more accurate in DC-100 MHz range
- Leads may act as inductors/capacitors
_1MHz_TO_900MHz.png)
