which double shielded coax?

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#2
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#7
davidsrsb said:
This one is quite good and not too thick
https://www.pasternack.com/images/ProductPDF/PE-C195.pdf
Unfortunately 50 Ohm means high capacitance
Click to expand...

Yes that looks good. I only need a couple of 1 foot cables so capacitance not a big deal. If I take 75 or 100 ohms, does that mean lower capacitance?

I need especially good mains and mains harmonic screening. Not sure if that is ever a concern for cable bakers.

Jan
 
#11
Sorry Jan,
I was trying to find the original Swensons article but withput success. It was on AA forum, it seems to me. So I posted first one that was on "serach".
Main thing is that Swenson uses insulation between the two shilding layers.
 
#12
I read with considerable interest the Audiomart quote from John Swenson and subsequent posts testing his theory linked to above in RajkoM's first post. It's been my practice to use copper braid to double shield signal wiring, but I've always also installed a single drain wire connecting one end of the double shield to chassis ground (typically a star ground that connects to house mains ground). As best I can tell, none of the tests address whether attaching the shield to ground offers any benefit.

Does anyone have any experience or informed thoughts on this? If the shield drain wires offer little or no benefit, I'd be very pleased to omit them.

MTIA, Derek
 
#13
Cable shield is an extension of the equipment casing. To be effective at RF (not the OPs focus) the shield has to be 360 degrees around the connector. Connectors with a solder tag are rubbish at RF.
The best shielded coax cables are the semi-rigid types
 
#16
This may be more expensive than you're looking for, but the following cable is sort of triple shielded. A copper foil shield with two OFC braid shields, 22awg solid core silver coductor:

Neotech NEVD-2001, Sonic Craft

It's somewhat challenging compared to other coax cables because it is so thick (8mm or 8.5mm with techflex). The only BNC that I know would fit would be the Oyaide:

Oyaide SLSB BNC Plugs - Set of 2 :782 Japan New 4562112764127 | eBay

The Oyaide are solid silver pin, but inside barrel is 9mm. Once again, this could be too expensive for what your looking for. Also, having an all silver conductor medium could be too much silver for your application.
 
#18
ainami said:
This may be more expensive than you're looking for, but the following cable is sort of triple shielded. A copper foil shield with two OFC braid shields, 22awg solid core silver coductor:

Neotech NEVD-2001, Sonic Craft

It's somewhat challenging compared to other coax cables because it is so thick (8mm or 8.5mm with techflex). The only BNC that I know would fit would be the Oyaide:

Oyaide SLSB BNC Plugs - Set of 2 :782 Japan New 4562112764127 | eBay

The Oyaide are solid silver pin, but inside barrel is 9mm. Once again, this could be too expensive for what your looking for. Also, having an all silver conductor medium could be too much silver for your application.
Click to expand...

Good tip, thanks. Diameter of cable is an issue for short cables like I need for test equipment.

Those special BNCs look more like a fashion product to me, so I let that pass.

Jan
 
#20

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