Looking for individually screened ribbon cable - Page 1
Forum section: electronics / general

author: CambridgeMart
author_rank: Regular Contributor
timestamp: May 15, 2021, 10:38:15 pm
content: I'm looking to make up some probe sets for my TLA logic analyser as used cables are insanely expensive; the original cable uses individually screened ribbon cable, as seen here:https://www.eevblog.com/forum/testgear/tektronix-714-logic-analyzer/?action=dlattach;attach=338150;imageI've searched high and low but cannot find anything like it. Has anyone come across this type of cable?

author: ucanel
author_rank: Regular Contributor
timestamp: May 15, 2021, 10:47:55 pm
content: If you could not find exact one,would it be enough to instead of using 8 row individually shielded cable use whole shielded 16 row cable and connect odd lines as shield either.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 15, 2021, 10:49:47 pm
content: Maybe old external SCSI cable? Not the same shape but it's designed to carry many high speed digital signals with minimal crosstalk between them.

author: jmelson
author_rank: Super Contributor
timestamp: May 16, 2021, 03:28:28 am
content: Spectra-Strip made a clone of the AMP coaxial ribbon cable. I first saw it in the backplane to backplane extension jumpers of the VAX 11/780. AMP stopped making it, but Spectra-Strip apparently kept the tooling and will make it on order. We needed a bunch, and had them make 2000 feet for us, 17 coax conductors, 50 Ohms. I think they can also make it in 75 and 91 Ohm impedance. We had our shop build a mass termination stripper and press.Jon

author: jmelson
author_rank: Super Contributor
timestamp: May 16, 2021, 03:32:18 am
content: My 9200 / DAS 720 uses some very wide ribbon, looks a lot like Chabin cables. It has two different wire sizes, I THINK the grounds are larger diameter, and there are two grounds between every signal. This is used with the 92A96 acq boards. The probe pods are totally passive (series resistor with small parallel cap.)Jon

author: smaultre
author_rank: Regular Contributor
timestamp: May 16, 2021, 05:09:29 am
content: On ebay there's tonn's of such probes from 20 to 100$ i dont think, that you find it much cheaper.https://www.ebay.com/itm/124187132017

author: amyk
author_rank: Super Contributor
timestamp: May 16, 2021, 05:41:29 am
content: The search keywords are "micro-coaxial ribbon cable". It is commonly used for LVDS connections to LCD panels.

author: CambridgeMart
author_rank: Regular Contributor
timestamp: May 16, 2021, 04:25:26 pm
content: Ebay ones at a reasonable price never seem to be available to the UK, e.g. from the auction listed above "Doesn't post to United Kingdom"

author: David Hess
author_rank: Super Contributor
timestamp: May 17, 2021, 04:26:10 pm
content: Quote from: ucanel on May 15, 2021, 10:47:55 pmThat is what I would try first because it is so simple and inexpensive. A step up would be to use adjacent pairs for a differential signal and ground every third wire for screening.

author: alexwhittemore
author_rank: Frequent Contributor
timestamp: May 17, 2021, 08:28:39 pm
content: I know Leopard Imaging makes their MIPI cables out of micro coax like this, but I have no idea where they source it and it looks too fine of pitch to be assembled practically by hand into a useful harness.

author: CambridgeMart
author_rank: Regular Contributor
timestamp: May 18, 2021, 09:46:34 pm
content: Looking through my cable stock, I found that RG178 is nice and small and will work nicely, so I'm going to make up my cables from this. I just need to find a neat way to keep them flat in a ribbon; failing that, I could bunch them up in expanding braided nylon sleeving I guess.

author: David Hess
author_rank: Super Contributor
timestamp: May 19, 2021, 12:57:28 am
content: You could braid the RG178 into flat cable.

author: ConKbot
author_rank: Super Contributor
timestamp: May 19, 2021, 06:06:01 am
content: The construction looks similar to how Samtec does their very high speed connectors. I.e.https://www.mouser.com/ProductDetail/Samtec/HLCD-30-1200-TR-TR-1?qs=%2Fha2pyFadug1ss0UNWiEgg7s0vKN4IHC0yaasB0PaXCvXLJ0db4i9gB6hBUOAvrQIf you can find a source that isn't $8/foot .047 coax may be of use for something dense.https://www.pasternack.com/precision-0.056-semirigid-replacement-50-ohm-coax-cable-fep-jacket-pe-p047-p.aspxFEP or PTFE highly suggested for your own sanity while soldering. Plus then you can use a thermal stripper for cable prep.It's just a shame pasternack is so expensive that cutting up a samtec cable is a more viable option

author: CambridgeMart
author_rank: Regular Contributor
timestamp: May 19, 2021, 08:52:21 pm
content: RTG-178, or at least a Chinese version of it, is available fairly cheaply; it's marginally larger than the Pasternack cable, but that won't be an issue in this case, it is PTFE jacketed (I wouldn't even look at PVC or PE cables for this job).

author: PlainName
author_rank: Super Contributor
timestamp: May 21, 2021, 01:24:53 am
content: QuoteClear UV-settable resin. I used this technique to make up a ribbon from discrete wires for a small connector. The photo is of my prototype, so could be a lot neater. Essentially, just dribble across the strip at whatever suitable intervals and fix with a UV LED in 10 secs. The resin could be the blindingly expensive Bondic, or the super-cheap stuff on Amazon for arts and crafts - both do the same thing as well as each other.