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I don't see a connection of the ground to the copper clad. But more than that, the leads are pretty long. A rule of thumb is that 1 cm is 10 nH, so it looks like you've got 40-50 nH in series with

I see two yellow wires for input and output but NO ground lead from the copper board to each of the coax connectors

EXACTLY... As I was walking away from the screen shot and getting ready to pull the plug! Again... NEATNESS COUNTS in this process.

Here's a plot of the expected response from Elsie

One thing you could also try is running the filter in a program like Elsie (which is free, for Windows only, though) and look at the S11 plot from Elsie and see if it looks like what you're measuring

Mitch, It looks like the ground (copper plane) of your filter is not connected to the grounds (outer conductors) of the cables. That would make a big difference. --John Gord

Hi Mitch. Dave can assist and we have confirmed that you filter in indeed set up for a 50 ohm source and load termination. The response is validation from a simple AC simulation. I looked at your

Hi Dave, S21 is the gray, I think (the not yellow one -- I'm color blind) print at the top right of the screen in the last two images I posted. It's line is flat at 0 dB across the frequency range

These plots compare reference impedance renormalization using S11, S21, S12, and S22 (yellow) with using just S11 and S21 (cyan). Shown are results for two different 10.7 MHz Murata ceramic filters

Please measure S21 instead of S11 using the NANOVNA! All S11 tells us is the match (which is pretty bad!). Dave - W?LEV [email protected]> wrote:

Thank you Alan. I've attached an image of the whole setup including the filter, the test rig and the VNA. Please note that I'm just using hookup wire to connect the filter to the testing rig--no SMA

1) Please post a schematic (already requested). 2) Did you measure the individual components before constructing the filter with them? 3) We assume the filter is designed for 50-ohms in and out?

One last item, on your scope pulse gen measurement. Dial your pulse gen back to 100 kHz, you should see the fidelity of the square wave as measured at the output load termination R. As you increase

Also, I would do your setup and cal over a frequency range of 100 kHz to 30 MHz. This way you should see the FLAT DC response of the filter, well below its cutoff and then see its roll off and

Confirmed and looks ok... Mitch. Assume that your layout is such that the inductors are ideally non coupled to each other, ideal each at right angles. The connectors are panel mount? Soldered their

Great. Give a few moments to run a check on what we should be seeing.

Here's the filter I built. Laid out on copper plated board. Capacitors are all grounded on the copper ground plane. Thanks. Mitch NK3H

Please post a schematic of your filter. Assume it is designed to operate in a 50 ohm system.

I've searched through the message list looking for symptoms similar to mine and didn't find anything. I'm somewhat new to this and would appreciate any help you can offer. I've been trying to get my

1 Hour... Good info... Excellent Intro.... Time well spent.... From R&S. https://event.on24.com/wcc/r/4871656/262AE419BBD73FA413BB90B6EEB73F0D?partnerref=mid_28133_na_m4c_inv-vna