TTL SMA isolation from front panel

[sbourdeauducq]

In each SMA-DIO the two banks are supposed to be galvanically isolated, but the grounds of the SMA connectors are shorted by the front panel.

[gkasprow]

Aren't there black shrinking tubes on the SMA connector installed?

[sbourdeauducq]

There are, but the nuts on the SMA connectors are resting directly on the varnished metal of the front panels. Even though the DC impedance between two banks that I measured is ~200k, this looks quite fragile. I was expecting some solid plastic washer like those on Urukul.

[gkasprow]

The front panel label is not conducting. 200k were placed intentionally to discharge potential ESD. Plastic washers dont fit. I couldnt find smaller ones that used in Urukul.

[hartytp]

I couldnt find smaller ones that used in Urukul.

I thought you were planning to 3D print these. Or did that work out too expensive?

[gkasprow]

I did dedicated one for Sayma RTM.
For SMA IO it's too expensive and the heat shrink tubes seem to work well.

[hartytp]

@gkasprow Sounds good. I was just curious!