N2PK VNA
From Note to self
Contents
Build notes
Master oscillator
I'm going to build the master oscillator from a Winner-Confield oscillator. Output needs to be adapted to 5V. -> Done, made a PCB
Parts
- CW470CT-ND Winner Confield oscillator
- TC1014-3.3VCT713CT-ND Microchip 3.3V Regulator
- MMBTH10-FDICT-ND (.28€) of KST10MTFCT-ND (0.18€) -> First one has a much larger stock. Is there something I am missing about the cheaper model?
- some caps and inductors for filtering 5V
- some resistors
Documentation
Notes
- The caps I bought
- For the anti-aliasing filters I use the redesign (with 0.15uH inductors instead of 0.22uH, as the latter are not in stock at digi-key)
Components
Missing
Bottom side
- R160a - R166a: I used 270k instead of 220k
- C115-117,126,127: 10uF 16V X5R 1210
- C180, C170: 27pF (filter redesign)
- R250: 3.3R 5% 0805 - I have 1.8R, 3.9R -> Use 3.9
- C250, 280,281,292: 10uF 16V Tant 20%
- C213, C290 100nF X7R
- C280,281,292
Top side
- C251 100nF X7R
- Q190,270: npn tx
- C125: 1uF 25V X7R 10%
Questions
- All caps seem to be NPO, X7R, X5R, or Tant. NPO = temperature independant, X7R & X5R = ceramic, Tant = tantalum. Problem: I only have an assortment, no other specs (prob. ceramic?)... According to Jacques, most small (pF) caps are NPO
- R160a - R166a should be 221K. They are part of (what I assume to be) an RC filter, and a load for that filter (the input impedance of that buffer IC is probably quite high). These are digital lines. I don't have those values, so I was thinking about taking 1k2/75pF for the RC filter, and 270k for the load. I don't see why it should be very critical.
- Build notes talk about using silver solder, this is not really necessary I presume.
Arduino interface
Interface Board Connections
Black 15 Ground Orange 2 RF DDS data Purple 3 LO DDS Data White 4 DDS W_Clk Blue 5 DDS FQ_UD Yellow 6 DDS Reset Orange-red 7 ADC SCK Brown 8 ADC nCS Green 11 ADC nSDO (PIN IS INVERTED IN VNA!!!)
Mailing list: interesting messages
3539 (!), 4482, 4457, 6164 (PSU), 3452 (!)