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Anyone using a Thunderbolt 3 hub?

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#1 calypsob

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Posted 18 March 2019 - 10:30 AM

Ive been reading alot about this thunderbolt 3 lately and apparently I have 2 ports which support this feature. It can deliver 40gbps at full bandwidth and I believe 100w of power? 

Im interested in the bandwidth aspect because I could potentially run any camera/filterwheel/autofocuser combo on the same hub down a single thunderbolt cable without having bandwidth issues.

Apparently you are currently limited by cable length, if you go longer than 3 feet the bandwidth drops from 40gbps to 20gbps, and 6.5' is the longest Thunderbolt 3 cable that you can use.

Supposedly they are working on a fiber optic version which has full bandwidth at a length of 65m, but if its anything like the dow corning usb 3 fiber optic cables, they will be pricey.

 

To the point, Im interested in getting a hub to match with a 6.5ft thunderbolt 3 cable, if anyone else is using one of these can you recommend a good brand?



#2 psandelle

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Posted 18 March 2019 - 02:42 PM

What are you plugging into it that you need that bandwidth? I don't know of a lot (if any) cameras, focusers, mounts, filter wheels, etc. that run off Thunderbolt 3 directly, so you end up having to get adapters/adapter cables to make things work...which just lower your bandwidth again. I have a laptop that has all Thunderbolt/USB-C (a subset) ports, but I cable it to my USB 3.0 hub off one port and an adapter off another (with Ethernet and a small USB 2.0 weather station/GPS off that adapter). The third port gets power. Plus, the USB 3.0 run can be 5 meters (I think I use 15 feet).

 

Paul



#3 Midnight Dan

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Posted 19 March 2019 - 09:12 AM

Filter wheels and autofocusers take nearly zero bandwidth.  Cameras do use a good amount, but nowhere near Thunderbolt 3 speeds.  I run two cameras and control my mount over a single USB-3 cable with no problems.  And you can get USB-3 repeater cables for a reasonable price so you can go some pretty good distances.

 

The bigger issue is power.  If you have high USB power needs for your gear, you'll just need to have a powered USB-3 hub at the mount.  I use a Startech USB-3 hub because it runs off of 12 volts DC like the rest of my gear.  Plus, while not cheap, Startech's hubs are super reliable and made for demanding environments:

https://www.startech...bs/~ST7300USBME

 

And, as Paul mentions above, I'm not aware of any gear that accepts Thunderbolt cables.

 

If you want to make the best USB usage of one of those Thunderbolt connectors, this is the best solution I've found:

https://www.startech...-c-hub~HB31C4AB

 

This plugs in to your Thunderbolt connector as a USB 3.1 Gen 2 device.  That port is actually a Thunderbolt/USB-3.1 port so either type of device will work.  It provides 4 USB 3.1 Gen 2 Outputs.  You'll get a total of 10Gbps bandwidth, shared among the 4 outputs, which is double that of standard USB-3, and far, far more than you'll need.  The outputs are compatible with all USB 1, 2, 3, 3.1 devices.

 

With that hub, you can run one USB-3 cable to your mount for all your astro gear, and plug in an external hard drive or two, and have plenty of bandwidth for them all.  I use one on my desktop Mac and run 2 high speed hard drives and a couple other low-bandwidth devices off of it.

 

-Dan


Edited by Midnight Dan, 19 March 2019 - 09:12 AM.

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#4 calypsob

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Posted 22 March 2019 - 07:50 AM

What are you plugging into it that you need that bandwidth? I don't know of a lot (if any) cameras, focusers, mounts, filter wheels, etc. that run off Thunderbolt 3 directly, so you end up having to get adapters/adapter cables to make things work...which just lower your bandwidth again. I have a laptop that has all Thunderbolt/USB-C (a subset) ports, but I cable it to my USB 3.0 hub off one port and an adapter off another (with Ethernet and a small USB 2.0 weather station/GPS off that adapter). The third port gets power. Plus, the USB 3.0 run can be 5 meters (I think I use 15 feet).

 

Paul

Well, Im referring to using a usb hub on a thunderbolt 3 port, I was not clear about that. What I dont like about usb 3 and 2 hubs is that they seems to have errors due to the bandwidth when you are using multiple devices. I guess I am assuming this would not happen with thunderbolt 3 because it is using 4 lanes PCIE.

I would like to run everything off of one thunderbolt 3 hub, some of the features I see on these things are unneccesary to me. Like for example the Lenovo thunderbolt 3 hub that they make for my P52s, it has ethernet and all of this 4k display output stuff, I just need a nice group of usb 3 hubs that will not interrupt one another. 

 

As for the cables, currently they run full bandwidth at less than 3.5' and half at 6.5'. Im fine with 20gbps, I dont think there is any way to flood a buffer with that much bandwidth. Just trying to figure out what hub to try, if anyone has any experience. I realize its relatively new tech so there is maybe like one person doing this.



#5 calypsob

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Posted 22 March 2019 - 07:53 AM

Filter wheels and autofocusers take nearly zero bandwidth.  Cameras do use a good amount, but nowhere near Thunderbolt 3 speeds.  I run two cameras and control my mount over a single USB-3 cable with no problems.  And you can get USB-3 repeater cables for a reasonable price so you can go some pretty good distances.

 

The bigger issue is power.  If you have high USB power needs for your gear, you'll just need to have a powered USB-3 hub at the mount.  I use a Startech USB-3 hub because it runs off of 12 volts DC like the rest of my gear.  Plus, while not cheap, Startech's hubs are super reliable and made for demanding environments:

https://www.startech...bs/~ST7300USBME

 

And, as Paul mentions above, I'm not aware of any gear that accepts Thunderbolt cables.

 

If you want to make the best USB usage of one of those Thunderbolt connectors, this is the best solution I've found:

https://www.startech...-c-hub~HB31C4AB

 

This plugs in to your Thunderbolt connector as a USB 3.1 Gen 2 device.  That port is actually a Thunderbolt/USB-3.1 port so either type of device will work.  It provides 4 USB 3.1 Gen 2 Outputs.  You'll get a total of 10Gbps bandwidth, shared among the 4 outputs, which is double that of standard USB-3, and far, far more than you'll need.  The outputs are compatible with all USB 1, 2, 3, 3.1 devices.

 

With that hub, you can run one USB-3 cable to your mount for all your astro gear, and plug in an external hard drive or two, and have plenty of bandwidth for them all.  I use one on my desktop Mac and run 2 high speed hard drives and a couple other low-bandwidth devices off of it.

 

-Dan

Thanks Dan, again Im just after usb3 being fed through the thunderbolt 3 port so I can utilize all 4 lanes of pcie. I have read about people having issues with usb 3 hubs so I was going to just bypass this and give thunderbolt 3 a shot and see if it works well. It looks like the startech tbolt 3- usb 3 hub you linked is exactly what im after. I see people recommending this brand alot so I will report back on my future findings.


Edited by calypsob, 22 March 2019 - 07:54 AM.


#6 psandelle

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Posted 22 March 2019 - 09:42 AM

Oh, what you're calling "hubs," I'm calling adapters because you're still plugging in slower stuff and not USB-C/Thunderbolt items. All the ones I've used (various makes) work for my Ethernet (to my mount) and my weather station. But my main stuff I run a USB-C/Thunderbolt cable from the laptop to a USB 3.0 hub. I've never had any problems with the industrial Startech USB 3.0 powered hubs having errors (7-port or 5 port) and I run them to the USB-c/Thunderbolt ports off my laptop (and never had any problems when the hubs were plugged into USB3.0 ports on my backup (and previous) laptops. I think there are just a lot of sucky hubs out there. Startechs aren't those. But I just run a cable (a really GOOD cable) with USB-C/Thunderbolt going from the laptop to the USB3.0 hub on the top of my telescope rig. Works great.

 

But maybe I'm missing something.

 

Paul


Edited by psandelle, 22 March 2019 - 01:04 PM.


#7 Midnight Dan

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Posted 22 March 2019 - 12:44 PM

>> USB-C/Lightning 

 

I think you meant USB-C/Thunderbolt? :-)  (Lightning connectors are used on iPhones.) So first, USB-C is a connector type.  Thunderbolt and USB 3 or USB 3.1 is the communications specification.  Of course, some of the communications types only use specific connector types, but they are different things.

 

There are 2 USB-C style connectors on the back of my Mac, which support either Thunderbolt 3 or USB 3.1 as communications specs.  Thunderbolt 3 has higher throughput than USB 3.1, but only for short distances as has been mentioned above.

 

>> what you're calling "hubs," I'm calling adapters ...

 

Well, in the case of the Startech 3.1 hub, it's really a hub.  Since the connector on the Mac supports USB 3.1, there is no adapter needed.  So the Startech 3.1 hub is just a hub, providing 4 USB 3.1 outputs, and connecting to one USB 3.1 port on the Mac.  The output ports on the hub are a different style than the Mac port, but they are both USB 3.1.

 

-Dan



#8 Jon Rista

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Posted 22 March 2019 - 12:59 PM

Well, Im referring to using a usb hub on a thunderbolt 3 port, I was not clear about that. What I dont like about usb 3 and 2 hubs is that they seems to have errors due to the bandwidth when you are using multiple devices. I guess I am assuming this would not happen with thunderbolt 3 because it is using 4 lanes PCIE.

I would like to run everything off of one thunderbolt 3 hub, some of the features I see on these things are unneccesary to me. Like for example the Lenovo thunderbolt 3 hub that they make for my P52s, it has ethernet and all of this 4k display output stuff, I just need a nice group of usb 3 hubs that will not interrupt one another. 

 

As for the cables, currently they run full bandwidth at less than 3.5' and half at 6.5'. Im fine with 20gbps, I dont think there is any way to flood a buffer with that much bandwidth. Just trying to figure out what hub to try, if anyone has any experience. I realize its relatively new tech so there is maybe like one person doing this.

You shouldn't have errors for devices connected through the hub to the computer.

 

If you are having errors, you should check to see if the port on your computer that you are plugging the hub into is also being used by the keyboard and mouse. The problem with input devices like these is they cause hardware level interrupts. So if you have kb/mouse traffic over the same root USB hub, then YES, those WILL by design interrupt other communications as they take low level hardware priority.

 

But multiple streams from devices connected through the hub to the computer? That should not result in errors. Not, at least, as long as you are not trying to double-book bandwidth (i.e. if you try to grab 80% bandwidth for two cameras, which is what the USB Limit/USB Traffic settings of QHY and ZWO cameras try to do, then that might cause problems). If you have multiple cameras, which with a guide camera is normal, just make sure the guide camera uses the lowest stable limit/traffic setting. Then let the main camera use as high of a limit/traffic setting as is stable. Usually you can set both to 30-40%, which means neither will try to reserve too much bandwidth...but that may slow down reads from the main camera which can increase overhead. I am not sure what other cameras, CCDs and the like, may offer here, but it is something to look into if you are having data transfer issues.

 

That said, keyboard/mouse on the same USB Root device in the computer is usually by far the biggest issue for reliable data transfer. Anything that issues hardware interrupts on the same channel is going to be highly disruptive. Move your USB hub to a different port on the computer to make sure you are not running your AP gear on the same root as the kb/mouse. 


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#9 psandelle

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Posted 22 March 2019 - 01:00 PM

>> USB-C/Lightning 

 

I think you meant USB-C/Thunderbolt? :-)  (Lightning connectors are used on iPhones.) So first, USB-C is a connector type.  Thunderbolt and USB 3 or USB 3.1 is the communications specification.  Of course, some of the communications types only use specific connector types, but they are different things.

 

There are 2 USB-C style connectors on the back of my Mac, which support either Thunderbolt 3 or USB 3.1 as communications specs.  Thunderbolt 3 has higher throughput than USB 3.1, but only for short distances as has been mentioned above.

 

>> what you're calling "hubs," I'm calling adapters ...

 

Well, in the case of the Startech 3.1 hub, it's really a hub.  Since the connector on the Mac supports USB 3.1, there is no adapter needed.  So the Startech 3.1 hub is just a hub, providing 4 USB 3.1 outputs, and connecting to one USB 3.1 port on the Mac.  The output ports on the hub are a different style than the Mac port, but they are both USB 3.1.

 

-Dan

Oops, you right. Thunder, Lightning...it was early. grin.gif I edited it so that anyone else reading won't get mixed up.

 

And, yeah, that was what I was trying to say: the Startech is the hub, the others I consider more adapter-types (since they're taking the USB-C/THUNDERbolt and converting to USB3.0 or Ethernet, etc.).

 

Paul


Edited by psandelle, 22 March 2019 - 01:04 PM.



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