Re: NanoVNA and LPF?


howard winwood G4GPF
 

Thats how I did mine, just used some perf board and socket strips aligned with filter pins,
Surprising how easy it is and you can see the performance of the filter as you adjust.

On 23 Jun 2021, at 17:12, Christopher Maness <christopher.maness@...> wrote:

Yeah.  I think I will try to build something out of perf board with some headers for the coils.  The caps are pretty easy to desolder from the perf board.

I guess I could find the VNA instructions for sweeping a LPF on YouTube.  I have not looked for one yet.

KQ6UP 

On Wed, Jun 23, 2021 at 9:08 AM N3MNT <bob@...> wrote:
Nothing special;  I used the adapter in the link below and installed wire sockets on an old LPF board from Hans.  The simply look at the filter cut off VS frequency and adjust the windings until the knee is at the lowest frequency you are operating.  I used the sockets so I would not have to solder and remove the torroids to adjust.  This method does induce some error, but it was negligible,
https://www.ph2lb.nl/blog/index.php?page=qrp-labs-filter-adapter-for-nanovna<20210105_150516.jpg><20210105_150415.jpg>



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