Combined coax + multiconductor cable

[jmw]

Are there any off-the-shelf cables that have 50 Ω coax and multiconductor wire bundled together? For example: what's in an active probe cable where there are wires for carrying power to the tip and coax for sending signal back? I could not find anything browsing Digikey but I don't know if I'm searching for the right name.

[coromonadalix]

I dont know,  we ordered in the past custom made dual rg316 coax and 5 wires in one special cable ...........

It is doable but the price it costed us 90$  a cable of 1.5  meter

[coppercone2]

because it was run through a extruder.

[DC1MC]

https://www.primuscable.com/collections/bundled-cable

https://compucableplususa.com/products/compucableplususa-best-bulk-multimedia-cable-in-wall-cable-multi-signal-access-cable-500-ft-type-1-cat-6-x-1-pc-rg-6-u-quad-shield-coaxial-cable-x-1-pc

https://simiacable.com/en/cctv-a-combined-cables/

[jonpaul]

Mogami and other cable fab can make anything you need but a setup fee and MOQ.

Easy to make a short cable with different conductors with large shrink tube or cable ties.

Frequently seen in broadcast studios

Jon

[switchabl]

For small runs (or one-offs) where custom cables aren't an option, braided cable sleeves are also worth a look.

[edavid]

https://www.primuscable.com/collections/bundled-cable

https://compucableplususa.com/products/compucableplususa-best-bulk-multimedia-cable-in-wall-cable-multi-signal-access-cable-500-ft-type-1-cat-6-x-1-pc-rg-6-u-quad-shield-coaxial-cable-x-1-pc

https://simiacable.com/en/cctv-a-combined-cables/

Those all have 75ohm coax though.

If OP can use that, VGA cable would also work.

[SeanB]

How about HDMI cables, where you do have some screened pairs, and also a few other pairs of non screened cable, in an overall screened sheath. Just have to get the longest ones you can get, or best price per foot, and chop off the plugs, or even just use them as is.

[edavid]

How about HDMI cables, where you do have some screened pairs, and also a few other pairs of non screened cable, in an overall screened sheath. Just have to get the longest ones you can get, or best price per foot, and chop off the plugs, or even just use them as is.

HDMI cable is shielded twisted pair, not coax as OP requested.

[jonpaul]

use RG/174/U or similar small dia 50 Ohm for smaller and more flexible cable.

High db/km attn but much easier to make multiconductor  cables.

https://www.l-com.com/Images/Downloadables/2D/RG174-100_2D.pdf

Jon

[coppercone2]

I wonder what would happen if you took a braided cable, and vacuum sealed it with silicone, so the silicone gets into the braid, then hung it up to dry. They have a long cure  time, the excess should drip off.

[Haenk]

May I suggest something like this:
https://en.wikipedia.org/wiki/DB13W3
Should be available at your vintage workstation dealer (commonly used on SUN and SGI back then), or maybe used on ebay.

[edavid]

May I suggest something like this:
https://en.wikipedia.org/wiki/DB13W3
Should be available at your vintage workstation dealer (commonly used on SUN and SGI back then), or maybe used on ebay.

That has the same issue of the coax being 75ohm, so it doesn't really have an advantage over a VGA cable.

[dmderev]

I was also looking for a solution for active probe and eventually I found three options:
1. Do it yourself with a nylon braid (simple but a bit less flexible than I wanted - with micro coax cable https://www.aliexpress.us/item/2251832707700559.html and wires inside). Using 36AWG teflon wires makes it thin overall.
2. Do it yourself, but with thin wall silicon tubing as jacket (same coax cable, tubing with 0.5mm wall, 4mm id). I saw that there are heat shrink silicone tubing available now, but I did not try how flexible they are after shrinking.
3. USB4 "coaxial" cable (it has 4 micro coaxial connectors and many wires, suitable for differential active probes). There are even "silicone" cables (https://www.aliexpress.us/item/3256805198860016.html) which, if you order as a single piece, will come at any length. Or you can order longest cable (not really good for USB4, but you can cut it in pieces).
As far as I know, LeCroy and Tektronix were ordering their cables directly. I used to have Tek cable but it had only two conductors in addition to coax cable.
In all these cases, the miniature teflon coax cables are suitable up to few GHz. The USB4 cables have more roll-off at >2-3Ghz. And high frequency active probes usually need 4+ wires for DC bias and controls.

[dmderev]

One other option - use 75Ohm cable (like S-Video) and put a series 25 ohm on the scope end. You will get a bit more division ratio (1:3) but it will be properly terminated. You will need 75 Ohms at the output of your buffer amplifier to properly terminate. There are different quality S-Video cables, some can work up to ~500+MHz. 

[Phil1977]

3. USB4 "coaxial" cable (it has 4 micro coaxial connectors and many wires, suitable for differential active probes). There are even "silicone" cables (https://www.aliexpress.us/item/3256805198860016.html) which, if you order as a single piece, will come at any length. Or you can order longest cable (not really good for USB4, but you can cut it in pieces).

Do you have any information about impedance and attenuation values of these coaxes? Maybe even a datasheet?