RE: Tap Tap Tap

shabaz — Thu, 24 Jul 2025 01:26:42 GMT

Hi Mike,

Wow great work! I don't know how I missed seeing this project earlier. I'm tempted to build one now too, maybe with N connector. Your results with the 50 ohm termination look very good.

Regarding the 100 ohm resistors, as [mention:4f57fc9d538949ad9eb336ddb9469bb8:e9ed411860ed4f2ba0265705b8793d05] mentions, if they can be shortened, it may improve things at the high frequencies. Those two resistors can be small since they don't carry a lot of current, and can then be soldered directly between center pin and the body, rather than to the screw, e.g. if those two resistors were 0603 or 0805 sized. But anyway, the results look extremely usable already.

You mentioned 100dB, 40dB is about the maximum that can be done reliably in a single metal enclosure, at least I've never managed more with DIY attenuation. Now that you have three, you could chain them to achieve 80 or 120 dB : ) I can see the need, I sometimes want 100 dB minimum too, to test radio receivers.

RE: Tap Tap Tap

DAB — Sat, 07 Jun 2025 19:32:17 GMT

Nice project.

RE: Tap Tap Tap

jc2048 — Wed, 04 Jun 2025 16:51:36 GMT

'I give them a "Good" grade. According to my NanoVNA, they start at about 33dB of attenuation at 3MHZ.'

I'm not very familiar with RF. Is a reading of -33dB for what is supposed to be -40dB really "good"?

RE: Tap Tap Tap

JWx — Wed, 04 Jun 2025 10:52:44 GMT

nice work!