Difference between revisions of "N2PK VNA"
From Note to self
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* [http://n2pk.com/VNA/VNA-below3-1.jpg PCB bottom side] | * [http://n2pk.com/VNA/VNA-below3-1.jpg PCB bottom side] | ||
== Notes == | == Notes == | ||
| − | + | ||
== Components == | == Components == | ||
=== Missing === | === Missing === | ||
* R250 - 3.3R 5% 0805 - I have 1.8R, 3.9R | * R250 - 3.3R 5% 0805 - I have 1.8R, 3.9R | ||
| + | * For R160a - R166a I used 270k instead of 220k | ||
=== Questions === | === 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?)... | * 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?)... | ||
* 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. | * 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. | ||
Revision as of 23:08, 15 October 2013
Documentation
Notes
Components
Missing
- R250 - 3.3R 5% 0805 - I have 1.8R, 3.9R
- For R160a - R166a I used 270k instead of 220k
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?)...
- 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.
