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Alan, exactly right. I failed to do it. I just posted a pic of the result of adding leads from copper plane to the ground on the test rig. Thank you. 73, Mitch

Correct. I failed to connect the ground plane to the connector grounds. I did just that with hookup wire soldered to the copper and connected to the ground of the test rig. A slight improvement. See

Alan, I agree 100% on neatness, lead length, etc. This was supposed to be just a test project in anticipation of properly building the filter. From your comments and others', it appears I need to use

Dave, Thank you for your reply. Very much appreciated. In order: 1) Done. 2) Yes, I measured all components with my LCR meter (DE 5000). 3) Correct. 50 ohms confirmed by others for this

HI Dave, Yes, it's there. The line goes across the very top of the screen, and the print shows "S21 LOGMAG 10 dB/-0.00 dB" in gray. Thanks for any help. Best, Mitch NK3H

The only measurement noted at the top of the screen was S11. Was S21 also there? I didn't see

Well, there's a long history of dead bug construction, and 3D sculptures. But it's the short leads thing that's biting you here. You can solder the capacitor lead to the copperclad really close and

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