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sinara-hw / Urukul

4 channel 1GS/s DDS (AD9910 or AD9912 variant)
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SMA stackup wrong, SMA cables loose #24

Closed Jochenwolf3 closed 5 years ago

Jochenwolf3 commented 5 years ago

Using standard SMA cables (e.g. JP1XJP1XF316-40 from Gigatronix), there is not enough exposed threading to put the SMA cables on. The plastic washer, tooth washer, and nut take up so much space on the thread that upon tightening the SMA cable nut, the cable still feels loose and can be wiggled around, indicating an unreliable connection:

20190408_142321

An extra ~3 mm of SMA threading is needed.

Workaround: remove the plastic washer from the stack, which creates just about enough space (and is fine for people who do not want their SMAs floated anyway)

Jochenwolf3 commented 5 years ago

This applies to Urukuls manufactured by both Creotech and Technosystem.

gkasprow commented 5 years ago

One option is to switch to longer SMA connectors like Telegartner J01151A0921. But they are very long. They are also far more expensive (30$/pc). I can also move the PCB edge to the panel by 1mm. This should solve the issue.

gkasprow commented 5 years ago

I moved them by 1mm to the panel.